Create instance and select physical device

3 files changed, 2290 insertions, 23 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..76e1fda
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+a.out
+a.exe
diff --git a/main.c b/main.c
index cf59f16..5bdedf3 100644
--- a/main.c
+++ b/main.c
@@ -14,10 +14,26 @@ OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.
 */
 
-// TODO: Create debug report callback
+/* Note: Due to the length of many function and variable names in the
+ *       Vulkan API, the line width of any Vulkan-related code here may be
+ *       extended from 80 columns to 120 colums to improve readability.
+ */
+
+/* The goal of this project is to create an entirely self-contained, embeddable
+ * Vulkan renderer. While dynamic linking directly against the system Vulkan
+ * loader is safe, it will crash if attempting to run on a system without it
+ * installed. By loading the Vulkan library dynamically, the application may
+ * gracefully close or even fall back to a different rendering API.
+ * Furthermore, Vulkan specifies that using functions retrieved via
+ * `vkGetDeviceProcAddr` may actually run faster than if the application were
+ * using the Vulkan loader directly due to bypassing the loader terminator.
+ *
+ * https://vulkan.lunarg.com/doc/sdk/1.0.61.1/windows/LoaderAndLayerInterface.html
+ */
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 
 #include <vulkan/vulkan.h>
 
@@ -29,17 +45,105 @@ PERFORMANCE OF THIS SOFTWARE.
 #include <vulkan/vulkan_xlib.h>
 #endif
 
+#define STB_SPRINTF_IMPLEMENTATION
+#include "stb_sprintf.h"
+
+#if defined(__GNUC__)
+#define APP_THREAD_LOCAL	__thread
+#else
+#define APP_THREAD_LOCAL	__declspec(thread)
+#endif
+
+/** Vulkan allocation callbacks if we ever decide to use them when debugging.
+ *
+ * This is put in a macro so we don't have to look for every Vulkan function
+ * that uses it.
+ */
+#define ALLOC_VK	NULL
+
+struct VulkanAPI {
+	void *handle;
+	PFN_vkGetInstanceProcAddr			vkGetInstanceProcAddr;
+	PFN_vkCreateInstance				vkCreateInstance;
+	PFN_vkDestroyInstance				vkDestroyInstance;
+	PFN_vkCreateDebugReportCallbackEXT		vkCreateDebugReportCallbackEXT;
+	PFN_vkDestroyDebugReportCallbackEXT		vkDestroyDebugReportCallbackEXT;
+	PFN_vkEnumeratePhysicalDevices			vkEnumeratePhysicalDevices;
+	PFN_vkGetPhysicalDeviceProperties		vkGetPhysicalDeviceProperties;
+	PFN_vkGetPhysicalDeviceQueueFamilyProperties	vkGetPhysicalDeviceQueueFamilyProperties;
+	PFN_vkGetPhysicalDeviceSurfaceSupportKHR	vkGetPhysicalDeviceSurfaceSupportKHR;
+	PFN_vkGetPhysicalDeviceMemoryProperties		vkGetPhysicalDeviceMemoryProperties;
+	PFN_vkEnumerateDeviceExtensionProperties	vkEnumerateDeviceExtensionProperties;
+};
+
 struct RenderVulkan {
-	/** Put `device` first in struct to reduce pointer arithmetic on most Vulkan functions */
-	VkDevice device;
+	struct VulkanAPI *api;
+	char *errMsg;
 	VkInstance instance;
+	VkDebugReportCallbackEXT debugCallback;
+	VkSurfaceKHR surface;
+	uint32_t graphicsIndex;
+	VkDevice device;
 };
 
 struct RenderVulkan *vk;
 
+#define ERRMSG_LEN	4096
+
+void setErrMsg(struct RenderVulkan *vk, const char *fmt, ...)
+{
+	if (!vk->errMsg) {
+		vk->errMsg = calloc(1, ERRMSG_LEN);
+	}
+	va_list args;
+	va_start(args, fmt);
+	stbsp_vsnprintf(vk->errMsg, ERRMSG_LEN, fmt, args);
+	va_end(args);
+}
+
+void clearErrMsg(struct RenderVulkan *vk)
+{
+	if (vk->errMsg) {
+		free(vk->errMsg);
+	}
+}
+
+const char *getErrMsg(struct RenderVulkan *vk)
+{
+	return vk->errMsg;
+}
+
 #if defined(_WIN32)
-void getRequiredInstanceExtensions(unsigned *nRequired, const char **extensions)
+#define VULKAN_SONAME_LATEST	"vulkan-1.dll"
+void *appDlopen(const char *soname)
+{
+	return LoadLibraryA(soname);
+}
+
+char *appDlerror()
+{
+	DWORD errCode = GetLastError();
+	static APP_THREAD_LOCAL char errStr[64];
+	stbsp_sprintf(errStr, "Dynamic Library Error: %d", errCode);
+	return errStr;
+}
+
+void *appDlsym(void *handle, const char *symbol)
+{
+	const uintptr_t ulAddr = (uintptr_t)GetProcAddress(handle, symbol);
+	return (void*)ulAddr;
+}
+
+int appDlclose(void *handle)
+{
+	return FreeLibrary(handle);
+}
+
+void getRequiredInstanceExtensions(void *windowCtx,
+		unsigned *nRequired,
+		const char **const extensions)
 {
+	(void)windowCtx;
 	static const char *const required[] = {
 		VK_KHR_SURFACE_EXTENSION_NAME,
 		VK_KHR_WIN32_SURFACE_EXTENSION_NAME
@@ -54,8 +158,38 @@ void getRequiredInstanceExtensions(unsigned *nRequired, const char **extensions)
 	}
 }
 #else
-void getRequiredInstanceExtensions(unsigned *nRequired, const char **const extensions)
+#define VULKAN_SONAME_LATEST	"libvulkan.so.1"
+#include <dlfcn.h>
+void *appDlopen(const char *soname)
 {
+	return dlopen(soname, RTLD_NOW);
+}
+
+char *appDlerror()
+{
+	return dlerror();
+}
+
+void *appDlsym(void *handle, const char *symbol)
+{
+	return dlsym(handle, symbol);
+}
+
+int appDlclose(void *handle)
+{
+	return dlclose(handle);
+}
+
+/* TODO: Linux actually has three possible surfaces: Xlib, XCB, and Wayland.
+ *       This should be figured out at runtime (without using #ifdefs).
+ *       In which case, `windowCtx` will be used to determine which to use.
+ *       As of now, Pugl (and LV2!) only supports Xlib.
+ */
+void getRequiredInstanceExtensions(void *windowCtx,
+		unsigned *nRequired,
+		const char **const extensions)
+{
+	(void)windowCtx;
 	static const char *const required[] = {
 		VK_KHR_SURFACE_EXTENSION_NAME,
 		VK_KHR_XLIB_SURFACE_EXTENSION_NAME
@@ -71,9 +205,46 @@ void getRequiredInstanceExtensions(unsigned *nRequired, const char **const exten
 }
 #endif
 
-void createInstance(struct RenderVulkan *vk,
-	const uint32_t nLayers, const char *const *layers,
-	const uint32_t nAdditional, const char *const *additionalExtensions)
+void *loadVulkanLibrary(const char *prefix)
+{
+	(void)prefix;	// TODO
+	void *handle = appDlopen(VULKAN_SONAME_LATEST);
+	return handle;
+}
+
+void loadVulkanGetInstanceProcAddrFunc(void *handle,
+		PFN_vkGetInstanceProcAddr *getInstanceProcAddrFunc)
+{
+	uintptr_t *ulGetInstanceProcAddrFunc = (uintptr_t*)getInstanceProcAddrFunc;
+	*ulGetInstanceProcAddrFunc = (uintptr_t)appDlsym(handle, "vkGetInstanceProcAddr");
+}
+
+int unloadVulkanLibrary(void *handle)
+{
+	if (handle) {
+		return appDlclose(handle);
+	}
+	return 0;
+}
+
+static VKAPI_ATTR VkBool32 VKAPI_CALL debugCallback(
+		VkDebugReportFlagsEXT flags,
+		VkDebugReportObjectTypeEXT objType,
+		uint64_t obj,
+		size_t location,
+		int32_t code,
+		const char *layerPrefix,
+		const char *msg,
+		void *userData
+		)
+{
+	fprintf(stderr, "\nValidation layer:\n%s\n\n", msg);
+	return VK_FALSE;
+}
+
+VkResult createInstance(struct RenderVulkan *vk,
+	const uint32_t nLayers, const char *const *const layers,
+	const uint32_t nAdditional, const char *const *const additionalExtensions)
 {
 	VkApplicationInfo appInfo = { 0 };
 	appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
@@ -81,15 +252,16 @@ void createInstance(struct RenderVulkan *vk,
 	appInfo.applicationVersion = VK_MAKE_VERSION(0, 1, 0);
 	appInfo.pEngineName = "Pugl Vulkan Test Engine";
 	appInfo.engineVersion = VK_MAKE_VERSION(0, 1, 0);
-	appInfo.apiVersion = VK_MAKE_VERSION(1, 0, 0);	// MoltenVK for macOS only supports Vulkan 1.0
+	/* MoltenVK for macOS currently only supports Vulkan 1.0 */
+	appInfo.apiVersion = VK_MAKE_VERSION(1, 0, 0);
 
 	unsigned i, j, nRequired;
-	getRequiredInstanceExtensions(&nRequired, NULL);
+	getRequiredInstanceExtensions(NULL, &nRequired, NULL);
 
 	const uint32_t nExtensions = nRequired + nAdditional;
 	const char **const extensions = malloc(sizeof(const char*) * nExtensions);
 
-	getRequiredInstanceExtensions(NULL, extensions);
+	getRequiredInstanceExtensions(NULL, NULL, extensions);
 	for (i = nRequired, j = 0; i < nExtensions; ++i, ++j) {
 		extensions[i] = additionalExtensions[j];
 	}
@@ -99,7 +271,7 @@ void createInstance(struct RenderVulkan *vk,
 	}
 
 	for (i = 0; i < nLayers; ++i) {
-		printf("Using instance layer:\t%s\n", layers[i]);
+		printf("Using instance layer:\t\t%s\n", layers[i]);
 	}
 
 	VkInstanceCreateInfo createInfo = { 0 };
@@ -110,21 +282,46 @@ void createInstance(struct RenderVulkan *vk,
 	createInfo.enabledExtensionCount = nExtensions;
 	createInfo.ppEnabledExtensionNames = extensions;
 
-	VkResult result;
-	if ((result = vkCreateInstance(&createInfo, NULL, &vk->instance))) {
-		exit(result);
+	VkResult result = VK_SUCCESS;
+	if ((result = vk->api->vkCreateInstance(&createInfo, ALLOC_VK, &vk->instance))) {
+		setErrMsg(vk, "Could not create Vulkan Instance: %d\n", result);
 	}
 	free(extensions);
+	return result;
 }
 
 /** Must not be called until all derivative objects are destroyed first */
 void destroyInstance(struct RenderVulkan *vk)
 {
-	vkDestroyInstance(vk->instance, NULL);
-	vk->instance = NULL;
+	vk->api->vkDestroyInstance(vk->instance, ALLOC_VK);
+	vk->instance = VK_NULL_HANDLE;
 }
 
-int main()
+/** This must work no matter the current state of `vk` */
+void renderVulkanDestroy(struct RenderVulkan *vk)
+{
+	if (vk) {
+		if (vk->debugCallback) {
+			/* `vk->debugCallback` implies `vk->api` and instance functions loaded */
+			vk->api->vkDestroyDebugReportCallbackEXT(vk->instance, vk->debugCallback, ALLOC_VK);
+		}
+		if (vk->instance) destroyInstance(vk);
+		if (vk->api) {
+			if (vk->api->handle) unloadVulkanLibrary(vk->api->handle);
+			free(vk->api);
+		}
+		if (vk->errMsg) free(vk->errMsg);
+		if (vk) free(vk);
+	}
+}
+
+/** Create a self-contained Vulkan instance and set up a debug reporter
+ *
+ * If errors occurred, the struct will be returned in an unusable state,
+ * and MUST be checked via `getErrMsg`. It MUST then be destroyed via
+ * `renderVulkanDestroy`.
+ * */
+struct RenderVulkan *renderVulkanCreate()
 {
 	static const char *const instanceLayers[] = {
 		"VK_LAYER_LUNARG_standard_validation"
@@ -135,12 +332,220 @@ int main()
 	};
 	const uint32_t nInstanceExtensions = sizeof(instanceExtensions) / sizeof(instanceExtensions[0]);
 
-	vk = malloc(sizeof(*vk));
-	createInstance(vk, nInstanceLayers, instanceLayers, nInstanceExtensions, instanceExtensions);
+	struct RenderVulkan *vk = calloc(1, sizeof(*vk));
+	vk->api = calloc(1, sizeof(*vk->api));
+
+	vk->api->handle = loadVulkanLibrary(NULL);
+	if (!vk->api->handle) {
+		setErrMsg(vk, "Error loading Vulkan shared library:\n%s\n", appDlerror());
+		return vk;
+	}
+
+	loadVulkanGetInstanceProcAddrFunc(vk->api->handle, &vk->api->vkGetInstanceProcAddr);
+	if (!vk->api->vkGetInstanceProcAddr) {
+		setErrMsg(vk, "Error loading `vkGetInstanceProcAddr`:\n%s", appDlerror());
+		return vk;
+	}
+
+	uintptr_t *const ulCreateInstance = (uintptr_t*)&vk->api->vkCreateInstance;
+	*ulCreateInstance = (uintptr_t)vk->api->vkGetInstanceProcAddr(NULL, "vkCreateInstance");
+	if (!vk->api->vkCreateInstance) {
+		setErrMsg(vk, "Error loading `vkCreateInstance`");
+		return vk;
+	}
+
+	VkResult result;
+	//if ((result = createInstance(vk, 0, NULL, 0, NULL))) {
+	if ((result = createInstance(vk, nInstanceLayers, instanceLayers, nInstanceExtensions, instanceExtensions))) {
+		return vk;
+	}
+
+	/* TODO: This could perhaps be generated */
+	static const char *const strErrLd = "Error loading function %s";
+
+	static const char *const strDestroyInstance = "vkDestroyInstance";
+	uintptr_t *const ulDestroyInstance = (uintptr_t*)&vk->api->vkDestroyInstance;
+	*ulDestroyInstance = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strDestroyInstance);
+	if (!vk->api->vkDestroyInstance) {
+		setErrMsg(vk, strErrLd, strDestroyInstance);
+		return vk;
+	}
+
+	/* It is okay if debug reporter functions are not resolved */
+	uintptr_t *ulCreateDebugReportCallbackEXT = (uintptr_t*)&vk->api->vkCreateDebugReportCallbackEXT;
+	*ulCreateDebugReportCallbackEXT = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, "vkCreateDebugReportCallbackEXT");
+
+	uintptr_t *ulDestroyDebugReportCallbackEXT = (uintptr_t*)&vk->api->vkDestroyDebugReportCallbackEXT;
+	*ulDestroyDebugReportCallbackEXT = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, "vkDestroyDebugReportCallbackEXT");
+
+	/* But not if we are unable to destroy a created debug reporter */
+	if (vk->api->vkCreateDebugReportCallbackEXT && !vk->api->vkDestroyDebugReportCallbackEXT) {
+		setErrMsg(vk, "No debug reporter destroy function loaded for corresponding create function\n");
+		return vk;
+	}
+
+	static const char *const strEnumeratePhysicalDevices = "vkEnumeratePhysicalDevices";
+	uintptr_t *ulEnumeratePhysicalDevices = (uintptr_t*)&vk->api->vkEnumeratePhysicalDevices;
+	*ulEnumeratePhysicalDevices = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strEnumeratePhysicalDevices);
+	if (!vk->api->vkEnumeratePhysicalDevices) {
+		setErrMsg(vk, strErrLd, strEnumeratePhysicalDevices);
+		return vk;
+	}
+
+	static const char *const strGetPhysicalDeviceProperties = "vkGetPhysicalDeviceProperties";
+	uintptr_t *ulGetPhysicalDeviceProperties = (uintptr_t*)&vk->api->vkGetPhysicalDeviceProperties;
+	*ulGetPhysicalDeviceProperties = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strGetPhysicalDeviceProperties);
+	if (!vk->api->vkGetPhysicalDeviceProperties) {
+		setErrMsg(vk, strErrLd, strGetPhysicalDeviceProperties);
+		return vk;
+	}
+
+	static const char *const strGetPhysicalDeviceQueueFamilyProperties = "vkGetPhysicalDeviceQueueFamilyProperties";
+	uintptr_t *ulGetPhysicalDeviceQueueFamilyProperties = (uintptr_t*)&vk->api->vkGetPhysicalDeviceQueueFamilyProperties;
+	*ulGetPhysicalDeviceQueueFamilyProperties = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strGetPhysicalDeviceQueueFamilyProperties);
+	if (!vk->api->vkGetPhysicalDeviceQueueFamilyProperties) {
+		setErrMsg(vk, strErrLd, strGetPhysicalDeviceQueueFamilyProperties);
+		return vk;
+	}
+
+	static const char *const strGetPhysicalDeviceSurfaceSupportKHR = "vkGetPhysicalDeviceSurfaceSupportKHR";
+	uintptr_t *ulGetPhysicalDeviceSurfaceSupportKHR = (uintptr_t*)&vk->api->vkGetPhysicalDeviceSurfaceSupportKHR;
+	*ulGetPhysicalDeviceSurfaceSupportKHR = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strGetPhysicalDeviceSurfaceSupportKHR);
+	if (!vk->api->vkGetPhysicalDeviceSurfaceSupportKHR) {
+		setErrMsg(vk, strErrLd, strGetPhysicalDeviceSurfaceSupportKHR);
+		return vk;
+	}
+
+	static const char *const strGetPhysicalDeviceMemoryProperties = "vkGetPhysicalDeviceMemoryProperties";
+	uintptr_t *ulGetPhysicalDeviceMemoryProperties = (uintptr_t*)&vk->api->vkGetPhysicalDeviceMemoryProperties;
+	*ulGetPhysicalDeviceMemoryProperties = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strGetPhysicalDeviceMemoryProperties);
+	if (!vk->api->vkGetPhysicalDeviceMemoryProperties) {
+		setErrMsg(vk, strErrLd, strGetPhysicalDeviceMemoryProperties);
+		return vk;
+	}
+
+	static const char *const strEnumerateDeviceExtensionProperties = "vkEnumerateDeviceExtensionProperties";
+	uintptr_t *ulEnumerateDeviceExtensionProperties = (uintptr_t*)&vk->api->vkEnumerateDeviceExtensionProperties;
+	*ulEnumerateDeviceExtensionProperties = (uintptr_t)vk->api->vkGetInstanceProcAddr(vk->instance, strEnumerateDeviceExtensionProperties);
+	if (!vk->api->vkEnumerateDeviceExtensionProperties) {
+		setErrMsg(vk, strErrLd, strEnumerateDeviceExtensionProperties);
+		return vk;
+	}
+
+	if (vk->api->vkCreateDebugReportCallbackEXT) {
+		VkDebugReportCallbackCreateInfoEXT debugInfo = { 0 };
+		debugInfo.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT;
+		debugInfo.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT | VK_DEBUG_REPORT_WARNING_BIT_EXT;
+		debugInfo.pfnCallback = debugCallback;
+		if ((result = vk->api->vkCreateDebugReportCallbackEXT(vk->instance,
+						&debugInfo, ALLOC_VK, &vk->debugCallback))) {
+			setErrMsg(vk, "Could not create debug reporter: %d", result);
+			return vk;
+		}
+	}
+
+	return vk;
+}
+
+int isDeviceSuitable(struct RenderVulkan *vk, VkPhysicalDevice pd)
+{
+	uint32_t nQueueFamilies;
+	vk->api->vkGetPhysicalDeviceQueueFamilyProperties(pd, &nQueueFamilies, NULL);
+	VkQueueFamilyProperties *queueProperties = malloc(nQueueFamilies * sizeof(*queueProperties));
+	vk->api->vkGetPhysicalDeviceQueueFamilyProperties(pd, &nQueueFamilies, queueProperties);
+	for (uint32_t i = 0; i < nQueueFamilies; ++i) {
+		printf("Queue Family %d queueCount:\t%d\n", i, queueProperties[i].queueCount);
+	}
+	uint32_t graphicsIndex;
+	for (graphicsIndex = 0; graphicsIndex < nQueueFamilies; ++graphicsIndex) {
+		if (queueProperties[graphicsIndex].queueFlags & VK_QUEUE_GRAPHICS_BIT) {
+			VkBool32 canSurface;
+			vk->api->vkGetPhysicalDeviceSurfaceSupportKHR(pd, graphicsIndex, vk->surface, &canSurface);
+			if (canSurface) break;
+		}
+	}
+	if (graphicsIndex >= nQueueFamilies) {
+		/* Some esoteric devices may have separate graphics and present queue families, or none at all.
+		 * An example would be a device without any video output plugs.
+		 * We only support graphics and present on the same queue family.
+		 */
+		return 0;
+	}
+	vk->graphicsIndex = graphicsIndex;
+	return 1;
+}
+
+void selectPhysicalDevice(struct RenderVulkan *vk)
+{
+	if (!vk->surface) {
+		setErrMsg(vk, "Cannot select a physical device without a surface");
+		return;
+	}
+	static const char *const strErrEnum = "Could not enumerate physical devices: %s";
+	static const char *const strWarnEnum = "Warn: Incomplete enumeration of physical devices";
+	uint32_t nDevices;
+	VkResult result;
+	if ((result = vk->api->vkEnumeratePhysicalDevices(vk->instance, &nDevices, NULL))) {
+		if (result != VK_INCOMPLETE) {
+			setErrMsg(vk, strErrEnum, result);
+			return;
+		} else {
+			fprintf(stderr, "%s\n", strWarnEnum);
+		}
+	}
+	if (!nDevices) {
+		setErrMsg(vk, "No physical devices found");
+		return;
+	}
+	VkPhysicalDevice *devices = malloc(nDevices * sizeof(*devices));
+	if ((result = vk->api->vkEnumeratePhysicalDevices(vk->instance, &nDevices, devices))) {
+		if (result != VK_INCOMPLETE) {
+			setErrMsg(vk, strErrEnum, result);
+			goto done;
+		} else {
+			fprintf(stderr, "%s\n", strWarnEnum);
+		}
+	}
+
+	for (uint32_t i = 0; i < nDevices; ++i) {
+		VkPhysicalDeviceProperties deviceProperties;
+		vk->api->vkGetPhysicalDeviceProperties(devices[i], &deviceProperties);
+		printf("Found physical device:\t`%s`\n", deviceProperties.deviceName);
+	}
+	for (uint32_t i = 0; i < nDevices; ++i) {
+		VkPhysicalDeviceProperties deviceProperties;
+		vk->api->vkGetPhysicalDeviceProperties(devices[i], &deviceProperties);
+		printf("Checking suitability for `%s`...\n", deviceProperties.deviceName);
+		if (isDeviceSuitable(vk, devices[i])) {
+			printf("Using physical device:\t`%s`\n", deviceProperties.deviceName);
+			break;
+		}
+		printf("Device `%s` not suitable\n", deviceProperties.deviceName);
+	}
+done:
+	free(devices);
+}
+
+int main()
+{
+	const char *errMsg = NULL;
+	struct RenderVulkan *vk = renderVulkanCreate();
+	if ((errMsg = getErrMsg(vk))) {
+		fprintf(stderr, "%s\n", errMsg);
+		renderVulkanDestroy(vk);
+		return 1;
+	}
+
 	printf("Created Vulkan Instance Successfully\n");
-	destroyInstance(vk);
-	free(vk);
-	vk = NULL;
+
+	selectPhysicalDevice(vk);
+	if ((errMsg = getErrMsg(vk))) {
+		fprintf(stderr, "%s\n", errMsg);
+		renderVulkanDestroy(vk);
+		return 1;
+	}
+
+	renderVulkanDestroy(vk);
 	return 0;
 }
 
diff --git a/stb_sprintf.h b/stb_sprintf.h
new file mode 100644
index 0000000..e3a3018
--- /dev/null
+++ b/stb_sprintf.h
@@ -0,0 +1,1860 @@
+// stb_sprintf - v1.06 - public domain snprintf() implementation
+// originally by Jeff Roberts / RAD Game Tools, 2015/10/20
+// http://github.com/nothings/stb
+//
+// allowed types:  sc uidBboXx p AaGgEef n
+// lengths      :  h ll j z t I64 I32 I
+//
+// Contributors:
+//    Fabian "ryg" Giesen (reformatting)
+//
+// Contributors (bugfixes):
+//    github:d26435
+//    github:trex78
+//    github:account-login
+//    Jari Komppa (SI suffixes)
+//    Rohit Nirmal
+//    Marcin Wojdyr
+//    Leonard Ritter
+//    Stefano Zanotti
+//    Adam Allison
+//
+// LICENSE:
+//
+//   See end of file for license information.
+
+#ifndef STB_SPRINTF_H_INCLUDE
+#define STB_SPRINTF_H_INCLUDE
+
+/*
+Single file sprintf replacement.
+
+Originally written by Jeff Roberts at RAD Game Tools - 2015/10/20.
+Hereby placed in public domain.
+
+This is a full sprintf replacement that supports everything that
+the C runtime sprintfs support, including float/double, 64-bit integers,
+hex floats, field parameters (%*.*d stuff), length reads backs, etc.
+
+Why would you need this if sprintf already exists?  Well, first off,
+it's *much* faster (see below). It's also much smaller than the CRT
+versions code-space-wise. We've also added some simple improvements
+that are super handy (commas in thousands, callbacks at buffer full,
+for example). Finally, the format strings for MSVC and GCC differ
+for 64-bit integers (among other small things), so this lets you use
+the same format strings in cross platform code.
+
+It uses the standard single file trick of being both the header file
+and the source itself. If you just include it normally, you just get
+the header file function definitions. To get the code, you include
+it from a C or C++ file and define STB_SPRINTF_IMPLEMENTATION first.
+
+It only uses va_args macros from the C runtime to do it's work. It
+does cast doubles to S64s and shifts and divides U64s, which does
+drag in CRT code on most platforms.
+
+It compiles to roughly 8K with float support, and 4K without.
+As a comparison, when using MSVC static libs, calling sprintf drags
+in 16K.
+
+API:
+====
+int stbsp_sprintf( char * buf, char const * fmt, ... )
+int stbsp_snprintf( char * buf, int count, char const * fmt, ... )
+  Convert an arg list into a buffer.  stbsp_snprintf always returns
+  a zero-terminated string (unlike regular snprintf).
+
+int stbsp_vsprintf( char * buf, char const * fmt, va_list va )
+int stbsp_vsnprintf( char * buf, int count, char const * fmt, va_list va )
+  Convert a va_list arg list into a buffer.  stbsp_vsnprintf always returns
+  a zero-terminated string (unlike regular snprintf).
+
+int stbsp_vsprintfcb( STBSP_SPRINTFCB * callback, void * user, char * buf, char const * fmt, va_list va )
+    typedef char * STBSP_SPRINTFCB( char const * buf, void * user, int len );
+  Convert into a buffer, calling back every STB_SPRINTF_MIN chars.
+  Your callback can then copy the chars out, print them or whatever.
+  This function is actually the workhorse for everything else.
+  The buffer you pass in must hold at least STB_SPRINTF_MIN characters.
+    // you return the next buffer to use or 0 to stop converting
+
+void stbsp_set_separators( char comma, char period )
+  Set the comma and period characters to use.
+
+FLOATS/DOUBLES:
+===============
+This code uses a internal float->ascii conversion method that uses
+doubles with error correction (double-doubles, for ~105 bits of
+precision).  This conversion is round-trip perfect - that is, an atof
+of the values output here will give you the bit-exact double back.
+
+One difference is that our insignificant digits will be different than
+with MSVC or GCC (but they don't match each other either).  We also
+don't attempt to find the minimum length matching float (pre-MSVC15
+doesn't either).
+
+If you don't need float or doubles at all, define STB_SPRINTF_NOFLOAT
+and you'll save 4K of code space.
+
+64-BIT INTS:
+============
+This library also supports 64-bit integers and you can use MSVC style or
+GCC style indicators (%I64d or %lld).  It supports the C99 specifiers
+for size_t and ptr_diff_t (%jd %zd) as well.
+
+EXTRAS:
+=======
+Like some GCCs, for integers and floats, you can use a ' (single quote)
+specifier and commas will be inserted on the thousands: "%'d" on 12345
+would print 12,345.
+
+For integers and floats, you can use a "$" specifier and the number
+will be converted to float and then divided to get kilo, mega, giga or
+tera and then printed, so "%$d" 1000 is "1.0 k", "%$.2d" 2536000 is
+"2.53 M", etc. For byte values, use two $:s, like "%$$d" to turn
+2536000 to "2.42 Mi". If you prefer JEDEC suffixes to SI ones, use three
+$:s: "%$$$d" -> "2.42 M". To remove the space between the number and the
+suffix, add "_" specifier: "%_$d" -> "2.53M".
+
+In addition to octal and hexadecimal conversions, you can print
+integers in binary: "%b" for 256 would print 100.
+
+PERFORMANCE vs MSVC 2008 32-/64-bit (GCC is even slower than MSVC):
+===================================================================
+"%d" across all 32-bit ints (4.8x/4.0x faster than 32-/64-bit MSVC)
+"%24d" across all 32-bit ints (4.5x/4.2x faster)
+"%x" across all 32-bit ints (4.5x/3.8x faster)
+"%08x" across all 32-bit ints (4.3x/3.8x faster)
+"%f" across e-10 to e+10 floats (7.3x/6.0x faster)
+"%e" across e-10 to e+10 floats (8.1x/6.0x faster)
+"%g" across e-10 to e+10 floats (10.0x/7.1x faster)
+"%f" for values near e-300 (7.9x/6.5x faster)
+"%f" for values near e+300 (10.0x/9.1x faster)
+"%e" for values near e-300 (10.1x/7.0x faster)
+"%e" for values near e+300 (9.2x/6.0x faster)
+"%.320f" for values near e-300 (12.6x/11.2x faster)
+"%a" for random values (8.6x/4.3x faster)
+"%I64d" for 64-bits with 32-bit values (4.8x/3.4x faster)
+"%I64d" for 64-bits > 32-bit values (4.9x/5.5x faster)
+"%s%s%s" for 64 char strings (7.1x/7.3x faster)
+"...512 char string..." ( 35.0x/32.5x faster!)
+*/
+
+#if defined(__has_feature)
+   #if __has_feature(address_sanitizer)
+      #define STBI__ASAN __attribute__((no_sanitize("address")))
+   #endif
+#endif
+#ifndef STBI__ASAN
+#define STBI__ASAN
+#endif
+
+#ifdef STB_SPRINTF_STATIC
+#define STBSP__PUBLICDEC static
+#define STBSP__PUBLICDEF static STBI__ASAN
+#else
+#ifdef __cplusplus
+#define STBSP__PUBLICDEC extern "C"
+#define STBSP__PUBLICDEF extern "C" STBI__ASAN
+#else
+#define STBSP__PUBLICDEC extern
+#define STBSP__PUBLICDEF STBI__ASAN
+#endif
+#endif
+
+#include <stdarg.h> // for va_list()
+#include <stddef.h> // size_t, ptrdiff_t
+
+#ifndef STB_SPRINTF_MIN
+#define STB_SPRINTF_MIN 512 // how many characters per callback
+#endif
+typedef char *STBSP_SPRINTFCB(char *buf, void *user, int len);
+
+#ifndef STB_SPRINTF_DECORATE
+#define STB_SPRINTF_DECORATE(name) stbsp_##name // define this before including if you want to change the names
+#endif
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(vsprintf)(char *buf, char const *fmt, va_list va);
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(vsnprintf)(char *buf, int count, char const *fmt, va_list va);
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(sprintf)(char *buf, char const *fmt, ...);
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(snprintf)(char *buf, int count, char const *fmt, ...);
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(vsprintfcb)(STBSP_SPRINTFCB *callback, void *user, char *buf, char const *fmt, va_list va);
+STBSP__PUBLICDEF void STB_SPRINTF_DECORATE(set_separators)(char comma, char period);
+
+#endif // STB_SPRINTF_H_INCLUDE
+
+#ifdef STB_SPRINTF_IMPLEMENTATION
+
+#include <stdlib.h> // for va_arg()
+
+#define stbsp__uint32 unsigned int
+#define stbsp__int32 signed int
+
+#ifdef _MSC_VER
+#define stbsp__uint64 unsigned __int64
+#define stbsp__int64 signed __int64
+#else
+#define stbsp__uint64 unsigned long long
+#define stbsp__int64 signed long long
+#endif
+#define stbsp__uint16 unsigned short
+
+#ifndef stbsp__uintptr
+#if defined(__ppc64__) || defined(__aarch64__) || defined(_M_X64) || defined(__x86_64__) || defined(__x86_64)
+#define stbsp__uintptr stbsp__uint64
+#else
+#define stbsp__uintptr stbsp__uint32
+#endif
+#endif
+
+#ifndef STB_SPRINTF_MSVC_MODE // used for MSVC2013 and earlier (MSVC2015 matches GCC)
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+#define STB_SPRINTF_MSVC_MODE
+#endif
+#endif
+
+#ifdef STB_SPRINTF_NOUNALIGNED // define this before inclusion to force stbsp_sprintf to always use aligned accesses
+#define STBSP__UNALIGNED(code)
+#else
+#define STBSP__UNALIGNED(code) code
+#endif
+
+#ifndef STB_SPRINTF_NOFLOAT
+// internal float utility functions
+static stbsp__int32 stbsp__real_to_str(char const **start, stbsp__uint32 *len, char *out, stbsp__int32 *decimal_pos, double value, stbsp__uint32 frac_digits);
+static stbsp__int32 stbsp__real_to_parts(stbsp__int64 *bits, stbsp__int32 *expo, double value);
+#define STBSP__SPECIAL 0x7000
+#endif
+
+static char stbsp__period = '.';
+static char stbsp__comma = ',';
+static struct
+{
+   short temp; // force next field to be 2-byte aligned
+   char pair[201];
+} stbsp__digitpair =
+{
+  0,
+   "00010203040506070809101112131415161718192021222324"
+   "25262728293031323334353637383940414243444546474849"
+   "50515253545556575859606162636465666768697071727374"
+   "75767778798081828384858687888990919293949596979899"
+};
+
+STBSP__PUBLICDEF void STB_SPRINTF_DECORATE(set_separators)(char pcomma, char pperiod)
+{
+   stbsp__period = pperiod;
+   stbsp__comma = pcomma;
+}
+
+#define STBSP__LEFTJUST 1
+#define STBSP__LEADINGPLUS 2
+#define STBSP__LEADINGSPACE 4
+#define STBSP__LEADING_0X 8
+#define STBSP__LEADINGZERO 16
+#define STBSP__INTMAX 32
+#define STBSP__TRIPLET_COMMA 64
+#define STBSP__NEGATIVE 128
+#define STBSP__METRIC_SUFFIX 256
+#define STBSP__HALFWIDTH 512
+#define STBSP__METRIC_NOSPACE 1024
+#define STBSP__METRIC_1024 2048
+#define STBSP__METRIC_JEDEC 4096
+
+static void stbsp__lead_sign(stbsp__uint32 fl, char *sign)
+{
+   sign[0] = 0;
+   if (fl & STBSP__NEGATIVE) {
+      sign[0] = 1;
+      sign[1] = '-';
+   } else if (fl & STBSP__LEADINGSPACE) {
+      sign[0] = 1;
+      sign[1] = ' ';
+   } else if (fl & STBSP__LEADINGPLUS) {
+      sign[0] = 1;
+      sign[1] = '+';
+   }
+}
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(vsprintfcb)(STBSP_SPRINTFCB *callback, void *user, char *buf, char const *fmt, va_list va)
+{
+   static char hex[] = "0123456789abcdefxp";
+   static char hexu[] = "0123456789ABCDEFXP";
+   char *bf;
+   char const *f;
+   int tlen = 0;
+
+   bf = buf;
+   f = fmt;
+   for (;;) {
+      stbsp__int32 fw, pr, tz;
+      stbsp__uint32 fl;
+
+      // macros for the callback buffer stuff
+      #define stbsp__chk_cb_bufL(bytes)                        \
+         {                                                     \
+            int len = (int)(bf - buf);                         \
+            if ((len + (bytes)) >= STB_SPRINTF_MIN) {          \
+               tlen += len;                                    \
+               if (0 == (bf = buf = callback(buf, user, len))) \
+                  goto done;                                   \
+            }                                                  \
+         }
+      #define stbsp__chk_cb_buf(bytes)    \
+         {                                \
+            if (callback) {               \
+               stbsp__chk_cb_bufL(bytes); \
+            }                             \
+         }
+      #define stbsp__flush_cb()                      \
+         {                                           \
+            stbsp__chk_cb_bufL(STB_SPRINTF_MIN - 1); \
+         } // flush if there is even one byte in the buffer
+      #define stbsp__cb_buf_clamp(cl, v)                \
+         cl = v;                                        \
+         if (callback) {                                \
+            int lg = STB_SPRINTF_MIN - (int)(bf - buf); \
+            if (cl > lg)                                \
+               cl = lg;                                 \
+         }
+
+      // fast copy everything up to the next % (or end of string)
+      for (;;) {
+         while (((stbsp__uintptr)f) & 3) {
+         schk1:
+            if (f[0] == '%')
+               goto scandd;
+         schk2:
+            if (f[0] == 0)
+               goto endfmt;
+            stbsp__chk_cb_buf(1);
+            *bf++ = f[0];
+            ++f;
+         }
+         for (;;) {
+            // Check if the next 4 bytes contain %(0x25) or end of string.
+            // Using the 'hasless' trick:
+            // https://graphics.stanford.edu/~seander/bithacks.html#HasLessInWord
+            stbsp__uint32 v, c;
+            v = *(stbsp__uint32 *)f;
+            c = (~v) & 0x80808080;
+            if (((v ^ 0x25252525) - 0x01010101) & c)
+               goto schk1;
+            if ((v - 0x01010101) & c)
+               goto schk2;
+            if (callback)
+               if ((STB_SPRINTF_MIN - (int)(bf - buf)) < 4)
+                  goto schk1;
+            #ifdef STB_SPRINTF_NOUNALIGNED
+                if(((stbsp__uintptr)bf) & 3) {
+                    bf[0] = f[0];
+                    bf[1] = f[1];
+                    bf[2] = f[2];
+                    bf[3] = f[3];
+                } else
+            #endif
+            {
+                *(stbsp__uint32 *)bf = v;
+            }
+            bf += 4;
+            f += 4;
+         }
+      }
+   scandd:
+
+      ++f;
+
+      // ok, we have a percent, read the modifiers first
+      fw = 0;
+      pr = -1;
+      fl = 0;
+      tz = 0;
+
+      // flags
+      for (;;) {
+         switch (f[0]) {
+         // if we have left justify
+         case '-':
+            fl |= STBSP__LEFTJUST;
+            ++f;
+            continue;
+         // if we have leading plus
+         case '+':
+            fl |= STBSP__LEADINGPLUS;
+            ++f;
+            continue;
+         // if we have leading space
+         case ' ':
+            fl |= STBSP__LEADINGSPACE;
+            ++f;
+            continue;
+         // if we have leading 0x
+         case '#':
+            fl |= STBSP__LEADING_0X;
+            ++f;
+            continue;
+         // if we have thousand commas
+         case '\'':
+            fl |= STBSP__TRIPLET_COMMA;
+            ++f;
+            continue;
+         // if we have kilo marker (none->kilo->kibi->jedec)
+         case '$':
+            if (fl & STBSP__METRIC_SUFFIX) {
+               if (fl & STBSP__METRIC_1024) {
+                  fl |= STBSP__METRIC_JEDEC;
+               } else {
+                  fl |= STBSP__METRIC_1024;
+               }
+            } else {
+               fl |= STBSP__METRIC_SUFFIX;
+            }
+            ++f;
+            continue;
+         // if we don't want space between metric suffix and number
+         case '_':
+            fl |= STBSP__METRIC_NOSPACE;
+            ++f;
+            continue;
+         // if we have leading zero
+         case '0':
+            fl |= STBSP__LEADINGZERO;
+            ++f;
+            goto flags_done;
+         default: goto flags_done;
+         }
+      }
+   flags_done:
+
+      // get the field width
+      if (f[0] == '*') {
+         fw = va_arg(va, stbsp__uint32);
+         ++f;
+      } else {
+         while ((f[0] >= '0') && (f[0] <= '9')) {
+            fw = fw * 10 + f[0] - '0';
+            f++;
+         }
+      }
+      // get the precision
+      if (f[0] == '.') {
+         ++f;
+         if (f[0] == '*') {
+            pr = va_arg(va, stbsp__uint32);
+            ++f;
+         } else {
+            pr = 0;
+            while ((f[0] >= '0') && (f[0] <= '9')) {
+               pr = pr * 10 + f[0] - '0';
+               f++;
+            }
+         }
+      }
+
+      // handle integer size overrides
+      switch (f[0]) {
+      // are we halfwidth?
+      case 'h':
+         fl |= STBSP__HALFWIDTH;
+         ++f;
+         break;
+      // are we 64-bit (unix style)
+      case 'l':
+         fl |= ((sizeof(long) == 8) ? STBSP__INTMAX : 0);
+         ++f;
+         if (f[0] == 'l') {
+            fl |= STBSP__INTMAX;
+            ++f;
+         }
+         break;
+      // are we 64-bit on intmax? (c99)
+      case 'j':
+         fl |= (sizeof(size_t) == 8) ? STBSP__INTMAX : 0;
+         ++f;
+         break;
+      // are we 64-bit on size_t or ptrdiff_t? (c99)
+      case 'z':
+         fl |= (sizeof(ptrdiff_t) == 8) ? STBSP__INTMAX : 0;
+         ++f;
+         break;
+      case 't':
+         fl |= (sizeof(ptrdiff_t) == 8) ? STBSP__INTMAX : 0;
+         ++f;
+         break;
+      // are we 64-bit (msft style)
+      case 'I':
+         if ((f[1] == '6') && (f[2] == '4')) {
+            fl |= STBSP__INTMAX;
+            f += 3;
+         } else if ((f[1] == '3') && (f[2] == '2')) {
+            f += 3;
+         } else {
+            fl |= ((sizeof(void *) == 8) ? STBSP__INTMAX : 0);
+            ++f;
+         }
+         break;
+      default: break;
+      }
+
+      // handle each replacement
+      switch (f[0]) {
+         #define STBSP__NUMSZ 512 // big enough for e308 (with commas) or e-307
+         char num[STBSP__NUMSZ];
+         char lead[8];
+         char tail[8];
+         char *s;
+         char const *h;
+         stbsp__uint32 l, n, cs;
+         stbsp__uint64 n64;
+#ifndef STB_SPRINTF_NOFLOAT
+         double fv;
+#endif
+         stbsp__int32 dp;
+         char const *sn;
+
+      case 's':
+         // get the string
+         s = va_arg(va, char *);
+         if (s == 0)
+            s = (char *)"null";
+         // get the length
+         sn = s;
+         for (;;) {
+            if ((((stbsp__uintptr)sn) & 3) == 0)
+               break;
+         lchk:
+            if (sn[0] == 0)
+               goto ld;
+            ++sn;
+         }
+         n = 0xffffffff;
+         if (pr >= 0) {
+            n = (stbsp__uint32)(sn - s);
+            if (n >= (stbsp__uint32)pr)
+               goto ld;
+            n = ((stbsp__uint32)(pr - n)) >> 2;
+         }
+         while (n) {
+            stbsp__uint32 v = *(stbsp__uint32 *)sn;
+            if ((v - 0x01010101) & (~v) & 0x80808080UL)
+               goto lchk;
+            sn += 4;
+            --n;
+         }
+         goto lchk;
+      ld:
+
+         l = (stbsp__uint32)(sn - s);
+         // clamp to precision
+         if (l > (stbsp__uint32)pr)
+            l = pr;
+         lead[0] = 0;
+         tail[0] = 0;
+         pr = 0;
+         dp = 0;
+         cs = 0;
+         // copy the string in
+         goto scopy;
+
+      case 'c': // char
+         // get the character
+         s = num + STBSP__NUMSZ - 1;
+         *s = (char)va_arg(va, int);
+         l = 1;
+         lead[0] = 0;
+         tail[0] = 0;
+         pr = 0;
+         dp = 0;
+         cs = 0;
+         goto scopy;
+
+      case 'n': // weird write-bytes specifier
+      {
+         int *d = va_arg(va, int *);
+         *d = tlen + (int)(bf - buf);
+      } break;
+
+#ifdef STB_SPRINTF_NOFLOAT
+      case 'A':              // float
+      case 'a':              // hex float
+      case 'G':              // float
+      case 'g':              // float
+      case 'E':              // float
+      case 'e':              // float
+      case 'f':              // float
+         va_arg(va, double); // eat it
+         s = (char *)"No float";
+         l = 8;
+         lead[0] = 0;
+         tail[0] = 0;
+         pr = 0;
+         dp = 0;
+         cs = 0;
+         goto scopy;
+#else
+      case 'A': // hex float
+      case 'a': // hex float
+         h = (f[0] == 'A') ? hexu : hex;
+         fv = va_arg(va, double);
+         if (pr == -1)
+            pr = 6; // default is 6
+         // read the double into a string
+         if (stbsp__real_to_parts((stbsp__int64 *)&n64, &dp, fv))
+            fl |= STBSP__NEGATIVE;
+
+         s = num + 64;
+
+         stbsp__lead_sign(fl, lead);
+
+         if (dp == -1023)
+            dp = (n64) ? -1022 : 0;
+         else
+            n64 |= (((stbsp__uint64)1) << 52);
+         n64 <<= (64 - 56);
+         if (pr < 15)
+            n64 += ((((stbsp__uint64)8) << 56) >> (pr * 4));
+// add leading chars
+
+#ifdef STB_SPRINTF_MSVC_MODE
+         *s++ = '0';
+         *s++ = 'x';
+#else
+         lead[1 + lead[0]] = '0';
+         lead[2 + lead[0]] = 'x';
+         lead[0] += 2;
+#endif
+         *s++ = h[(n64 >> 60) & 15];
+         n64 <<= 4;
+         if (pr)
+            *s++ = stbsp__period;
+         sn = s;
+
+         // print the bits
+         n = pr;
+         if (n > 13)
+            n = 13;
+         if (pr > (stbsp__int32)n)
+            tz = pr - n;
+         pr = 0;
+         while (n--) {
+            *s++ = h[(n64 >> 60) & 15];
+            n64 <<= 4;
+         }
+
+         // print the expo
+         tail[1] = h[17];
+         if (dp < 0) {
+            tail[2] = '-';
+            dp = -dp;
+         } else
+            tail[2] = '+';
+         n = (dp >= 1000) ? 6 : ((dp >= 100) ? 5 : ((dp >= 10) ? 4 : 3));
+         tail[0] = (char)n;
+         for (;;) {
+            tail[n] = '0' + dp % 10;
+            if (n <= 3)
+               break;
+            --n;
+            dp /= 10;
+         }
+
+         dp = (int)(s - sn);
+         l = (int)(s - (num + 64));
+         s = num + 64;
+         cs = 1 + (3 << 24);
+         goto scopy;
+
+      case 'G': // float
+      case 'g': // float
+         h = (f[0] == 'G') ? hexu : hex;
+         fv = va_arg(va, double);
+         if (pr == -1)
+            pr = 6;
+         else if (pr == 0)
+            pr = 1; // default is 6
+         // read the double into a string
+         if (stbsp__real_to_str(&sn, &l, num, &dp, fv, (pr - 1) | 0x80000000))
+            fl |= STBSP__NEGATIVE;
+
+         // clamp the precision and delete extra zeros after clamp
+         n = pr;
+         if (l > (stbsp__uint32)pr)
+            l = pr;
+         while ((l > 1) && (pr) && (sn[l - 1] == '0')) {
+            --pr;
+            --l;
+         }
+
+         // should we use %e
+         if ((dp <= -4) || (dp > (stbsp__int32)n)) {
+            if (pr > (stbsp__int32)l)
+               pr = l - 1;
+            else if (pr)
+               --pr; // when using %e, there is one digit before the decimal
+            goto doexpfromg;
+         }
+         // this is the insane action to get the pr to match %g semantics for %f
+         if (dp > 0) {
+            pr = (dp < (stbsp__int32)l) ? l - dp : 0;
+         } else {
+            pr = -dp + ((pr > (stbsp__int32)l) ? (stbsp__int32) l : pr);
+         }
+         goto dofloatfromg;
+
+      case 'E': // float
+      case 'e': // float
+         h = (f[0] == 'E') ? hexu : hex;
+         fv = va_arg(va, double);
+         if (pr == -1)
+            pr = 6; // default is 6
+         // read the double into a string
+         if (stbsp__real_to_str(&sn, &l, num, &dp, fv, pr | 0x80000000))
+            fl |= STBSP__NEGATIVE;
+      doexpfromg:
+         tail[0] = 0;
+         stbsp__lead_sign(fl, lead);
+         if (dp == STBSP__SPECIAL) {
+            s = (char *)sn;
+            cs = 0;
+            pr = 0;
+            goto scopy;
+         }
+         s = num + 64;
+         // handle leading chars
+         *s++ = sn[0];
+
+         if (pr)
+            *s++ = stbsp__period;
+
+         // handle after decimal
+         if ((l - 1) > (stbsp__uint32)pr)
+            l = pr + 1;
+         for (n = 1; n < l; n++)
+            *s++ = sn[n];
+         // trailing zeros
+         tz = pr - (l - 1);
+         pr = 0;
+         // dump expo
+         tail[1] = h[0xe];
+         dp -= 1;
+         if (dp < 0) {
+            tail[2] = '-';
+            dp = -dp;
+         } else
+            tail[2] = '+';
+#ifdef STB_SPRINTF_MSVC_MODE
+         n = 5;
+#else
+         n = (dp >= 100) ? 5 : 4;
+#endif
+         tail[0] = (char)n;
+         for (;;) {
+            tail[n] = '0' + dp % 10;
+            if (n <= 3)
+               break;
+            --n;
+            dp /= 10;
+         }
+         cs = 1 + (3 << 24); // how many tens
+         goto flt_lead;
+
+      case 'f': // float
+         fv = va_arg(va, double);
+      doafloat:
+         // do kilos
+         if (fl & STBSP__METRIC_SUFFIX) {
+            double divisor;
+            divisor = 1000.0f;
+            if (fl & STBSP__METRIC_1024)
+               divisor = 1024.0;
+            while (fl < 0x4000000) {
+               if ((fv < divisor) && (fv > -divisor))
+                  break;
+               fv /= divisor;
+               fl += 0x1000000;
+            }
+         }
+         if (pr == -1)
+            pr = 6; // default is 6
+         // read the double into a string
+         if (stbsp__real_to_str(&sn, &l, num, &dp, fv, pr))
+            fl |= STBSP__NEGATIVE;
+      dofloatfromg:
+         tail[0] = 0;
+         stbsp__lead_sign(fl, lead);
+         if (dp == STBSP__SPECIAL) {
+            s = (char *)sn;
+            cs = 0;
+            pr = 0;
+            goto scopy;
+         }
+         s = num + 64;
+
+         // handle the three decimal varieties
+         if (dp <= 0) {
+            stbsp__int32 i;
+            // handle 0.000*000xxxx
+            *s++ = '0';
+            if (pr)
+               *s++ = stbsp__period;
+            n = -dp;
+            if ((stbsp__int32)n > pr)
+               n = pr;
+            i = n;
+            while (i) {
+               if ((((stbsp__uintptr)s) & 3) == 0)
+                  break;
+               *s++ = '0';
+               --i;
+            }
+            while (i >= 4) {
+               *(stbsp__uint32 *)s = 0x30303030;
+               s += 4;
+               i -= 4;
+            }
+            while (i) {
+               *s++ = '0';
+               --i;
+            }
+            if ((stbsp__int32)(l + n) > pr)
+               l = pr - n;
+            i = l;
+            while (i) {
+               *s++ = *sn++;
+               --i;
+            }
+            tz = pr - (n + l);
+            cs = 1 + (3 << 24); // how many tens did we write (for commas below)
+         } else {
+            cs = (fl & STBSP__TRIPLET_COMMA) ? ((600 - (stbsp__uint32)dp) % 3) : 0;
+            if ((stbsp__uint32)dp >= l) {
+               // handle xxxx000*000.0
+               n = 0;
+               for (;;) {
+                  if ((fl & STBSP__TRIPLET_COMMA) && (++cs == 4)) {
+                     cs = 0;
+                     *s++ = stbsp__comma;
+                  } else {
+                     *s++ = sn[n];
+                     ++n;
+                     if (n >= l)
+                        break;
+                  }
+               }
+               if (n < (stbsp__uint32)dp) {
+                  n = dp - n;
+                  if ((fl & STBSP__TRIPLET_COMMA) == 0) {
+                     while (n) {
+                        if ((((stbsp__uintptr)s) & 3) == 0)
+                           break;
+                        *s++ = '0';
+                        --n;
+                     }
+                     while (n >= 4) {
+                        *(stbsp__uint32 *)s = 0x30303030;
+                        s += 4;
+                        n -= 4;
+                     }
+                  }
+                  while (n) {
+                     if ((fl & STBSP__TRIPLET_COMMA) && (++cs == 4)) {
+                        cs = 0;
+                        *s++ = stbsp__comma;
+                     } else {
+                        *s++ = '0';
+                        --n;
+                     }
+                  }
+               }
+               cs = (int)(s - (num + 64)) + (3 << 24); // cs is how many tens
+               if (pr) {
+                  *s++ = stbsp__period;
+                  tz = pr;
+               }
+            } else {
+               // handle xxxxx.xxxx000*000
+               n = 0;
+               for (;;) {
+                  if ((fl & STBSP__TRIPLET_COMMA) && (++cs == 4)) {
+                     cs = 0;
+                     *s++ = stbsp__comma;
+                  } else {
+                     *s++ = sn[n];
+                     ++n;
+                     if (n >= (stbsp__uint32)dp)
+                        break;
+                  }
+               }
+               cs = (int)(s - (num + 64)) + (3 << 24); // cs is how many tens
+               if (pr)
+                  *s++ = stbsp__period;
+               if ((l - dp) > (stbsp__uint32)pr)
+                  l = pr + dp;
+               while (n < l) {
+                  *s++ = sn[n];
+                  ++n;
+               }
+               tz = pr - (l - dp);
+            }
+         }
+         pr = 0;
+
+         // handle k,m,g,t
+         if (fl & STBSP__METRIC_SUFFIX) {
+            char idx;
+            idx = 1;
+            if (fl & STBSP__METRIC_NOSPACE)
+               idx = 0;
+            tail[0] = idx;
+            tail[1] = ' ';
+            {
+               if (fl >> 24) { // SI kilo is 'k', JEDEC and SI kibits are 'K'.
+                  if (fl & STBSP__METRIC_1024)
+                     tail[idx + 1] = "_KMGT"[fl >> 24];
+                  else
+                     tail[idx + 1] = "_kMGT"[fl >> 24];
+                  idx++;
+                  // If printing kibits and not in jedec, add the 'i'.
+                  if (fl & STBSP__METRIC_1024 && !(fl & STBSP__METRIC_JEDEC)) {
+                     tail[idx + 1] = 'i';
+                     idx++;
+                  }
+                  tail[0] = idx;
+               }
+            }
+         };
+
+      flt_lead:
+         // get the length that we copied
+         l = (stbsp__uint32)(s - (num + 64));
+         s = num + 64;
+         goto scopy;
+#endif
+
+      case 'B': // upper binary
+      case 'b': // lower binary
+         h = (f[0] == 'B') ? hexu : hex;
+         lead[0] = 0;
+         if (fl & STBSP__LEADING_0X) {
+            lead[0] = 2;
+            lead[1] = '0';
+            lead[2] = h[0xb];
+         }
+         l = (8 << 4) | (1 << 8);
+         goto radixnum;
+
+      case 'o': // octal
+         h = hexu;
+         lead[0] = 0;
+         if (fl & STBSP__LEADING_0X) {
+            lead[0] = 1;
+            lead[1] = '0';
+         }
+         l = (3 << 4) | (3 << 8);
+         goto radixnum;
+
+      case 'p': // pointer
+         fl |= (sizeof(void *) == 8) ? STBSP__INTMAX : 0;
+         pr = sizeof(void *) * 2;
+         fl &= ~STBSP__LEADINGZERO; // 'p' only prints the pointer with zeros
+                                    // fall through - to X
+
+      case 'X': // upper hex
+      case 'x': // lower hex
+         h = (f[0] == 'X') ? hexu : hex;
+         l = (4 << 4) | (4 << 8);
+         lead[0] = 0;
+         if (fl & STBSP__LEADING_0X) {
+            lead[0] = 2;
+            lead[1] = '0';
+            lead[2] = h[16];
+         }
+      radixnum:
+         // get the number
+         if (fl & STBSP__INTMAX)
+            n64 = va_arg(va, stbsp__uint64);
+         else
+            n64 = va_arg(va, stbsp__uint32);
+
+         s = num + STBSP__NUMSZ;
+         dp = 0;
+         // clear tail, and clear leading if value is zero
+         tail[0] = 0;
+         if (n64 == 0) {
+            lead[0] = 0;
+            if (pr == 0) {
+               l = 0;
+               cs = (((l >> 4) & 15)) << 24;
+               goto scopy;
+            }
+         }
+         // convert to string
+         for (;;) {
+            *--s = h[n64 & ((1 << (l >> 8)) - 1)];
+            n64 >>= (l >> 8);
+            if (!((n64) || ((stbsp__int32)((num + STBSP__NUMSZ) - s) < pr)))
+               break;
+            if (fl & STBSP__TRIPLET_COMMA) {
+               ++l;
+               if ((l & 15) == ((l >> 4) & 15)) {
+                  l &= ~15;
+                  *--s = stbsp__comma;
+               }
+            }
+         };
+         // get the tens and the comma pos
+         cs = (stbsp__uint32)((num + STBSP__NUMSZ) - s) + ((((l >> 4) & 15)) << 24);
+         // get the length that we copied
+         l = (stbsp__uint32)((num + STBSP__NUMSZ) - s);
+         // copy it
+         goto scopy;
+
+      case 'u': // unsigned
+      case 'i':
+      case 'd': // integer
+         // get the integer and abs it
+         if (fl & STBSP__INTMAX) {
+            stbsp__int64 i64 = va_arg(va, stbsp__int64);
+            n64 = (stbsp__uint64)i64;
+            if ((f[0] != 'u') && (i64 < 0)) {
+               n64 = (stbsp__uint64)-i64;
+               fl |= STBSP__NEGATIVE;
+            }
+         } else {
+            stbsp__int32 i = va_arg(va, stbsp__int32);
+            n64 = (stbsp__uint32)i;
+            if ((f[0] != 'u') && (i < 0)) {
+               n64 = (stbsp__uint32)-i;
+               fl |= STBSP__NEGATIVE;
+            }
+         }
+
+#ifndef STB_SPRINTF_NOFLOAT
+         if (fl & STBSP__METRIC_SUFFIX) {
+            if (n64 < 1024)
+               pr = 0;
+            else if (pr == -1)
+               pr = 1;
+            fv = (double)(stbsp__int64)n64;
+            goto doafloat;
+         }
+#endif
+
+         // convert to string
+         s = num + STBSP__NUMSZ;
+         l = 0;
+
+         for (;;) {
+            // do in 32-bit chunks (avoid lots of 64-bit divides even with constant denominators)
+            char *o = s - 8;
+            if (n64 >= 100000000) {
+               n = (stbsp__uint32)(n64 % 100000000);
+               n64 /= 100000000;
+            } else {
+               n = (stbsp__uint32)n64;
+               n64 = 0;
+            }
+            if ((fl & STBSP__TRIPLET_COMMA) == 0) {
+               do {
+                  s -= 2;
+                  *(stbsp__uint16 *)s = *(stbsp__uint16 *)&stbsp__digitpair.pair[(n % 100) * 2];
+                  n /= 100;
+               } while (n);
+            }
+            while (n) {
+               if ((fl & STBSP__TRIPLET_COMMA) && (l++ == 3)) {
+                  l = 0;
+                  *--s = stbsp__comma;
+                  --o;
+               } else {
+                  *--s = (char)(n % 10) + '0';
+                  n /= 10;
+               }
+            }
+            if (n64 == 0) {
+               if ((s[0] == '0') && (s != (num + STBSP__NUMSZ)))
+                  ++s;
+               break;
+            }
+            while (s != o)
+               if ((fl & STBSP__TRIPLET_COMMA) && (l++ == 3)) {
+                  l = 0;
+                  *--s = stbsp__comma;
+                  --o;
+               } else {
+                  *--s = '0';
+               }
+         }
+
+         tail[0] = 0;
+         stbsp__lead_sign(fl, lead);
+
+         // get the length that we copied
+         l = (stbsp__uint32)((num + STBSP__NUMSZ) - s);
+         if (l == 0) {
+            *--s = '0';
+            l = 1;
+         }
+         cs = l + (3 << 24);
+         if (pr < 0)
+            pr = 0;
+
+      scopy:
+         // get fw=leading/trailing space, pr=leading zeros
+         if (pr < (stbsp__int32)l)
+            pr = l;
+         n = pr + lead[0] + tail[0] + tz;
+         if (fw < (stbsp__int32)n)
+            fw = n;
+         fw -= n;
+         pr -= l;
+
+         // handle right justify and leading zeros
+         if ((fl & STBSP__LEFTJUST) == 0) {
+            if (fl & STBSP__LEADINGZERO) // if leading zeros, everything is in pr
+            {
+               pr = (fw > pr) ? fw : pr;
+               fw = 0;
+            } else {
+               fl &= ~STBSP__TRIPLET_COMMA; // if no leading zeros, then no commas
+            }
+         }
+
+         // copy the spaces and/or zeros
+         if (fw + pr) {
+            stbsp__int32 i;
+            stbsp__uint32 c;
+
+            // copy leading spaces (or when doing %8.4d stuff)
+            if ((fl & STBSP__LEFTJUST) == 0)
+               while (fw > 0) {
+                  stbsp__cb_buf_clamp(i, fw);
+                  fw -= i;
+                  while (i) {
+                     if ((((stbsp__uintptr)bf) & 3) == 0)
+                        break;
+                     *bf++ = ' ';
+                     --i;
+                  }
+                  while (i >= 4) {
+                     *(stbsp__uint32 *)bf = 0x20202020;
+                     bf += 4;
+                     i -= 4;
+                  }
+                  while (i) {
+                     *bf++ = ' ';
+                     --i;
+                  }
+                  stbsp__chk_cb_buf(1);
+               }
+
+            // copy leader
+            sn = lead + 1;
+            while (lead[0]) {
+               stbsp__cb_buf_clamp(i, lead[0]);
+               lead[0] -= (char)i;
+               while (i) {
+                  *bf++ = *sn++;
+                  --i;
+               }
+               stbsp__chk_cb_buf(1);
+            }
+
+            // copy leading zeros
+            c = cs >> 24;
+            cs &= 0xffffff;
+            cs = (fl & STBSP__TRIPLET_COMMA) ? ((stbsp__uint32)(c - ((pr + cs) % (c + 1)))) : 0;
+            while (pr > 0) {
+               stbsp__cb_buf_clamp(i, pr);
+               pr -= i;
+               if ((fl & STBSP__TRIPLET_COMMA) == 0) {
+                  while (i) {
+                     if ((((stbsp__uintptr)bf) & 3) == 0)
+                        break;
+                     *bf++ = '0';
+                     --i;
+                  }
+                  while (i >= 4) {
+                     *(stbsp__uint32 *)bf = 0x30303030;
+                     bf += 4;
+                     i -= 4;
+                  }
+               }
+               while (i) {
+                  if ((fl & STBSP__TRIPLET_COMMA) && (cs++ == c)) {
+                     cs = 0;
+                     *bf++ = stbsp__comma;
+                  } else
+                     *bf++ = '0';
+                  --i;
+               }
+               stbsp__chk_cb_buf(1);
+            }
+         }
+
+         // copy leader if there is still one
+         sn = lead + 1;
+         while (lead[0]) {
+            stbsp__int32 i;
+            stbsp__cb_buf_clamp(i, lead[0]);
+            lead[0] -= (char)i;
+            while (i) {
+               *bf++ = *sn++;
+               --i;
+            }
+            stbsp__chk_cb_buf(1);
+         }
+
+         // copy the string
+         n = l;
+         while (n) {
+            stbsp__int32 i;
+            stbsp__cb_buf_clamp(i, n);
+            n -= i;
+            STBSP__UNALIGNED(while (i >= 4) {
+               *(stbsp__uint32 *)bf = *(stbsp__uint32 *)s;
+               bf += 4;
+               s += 4;
+               i -= 4;
+            })
+            while (i) {
+               *bf++ = *s++;
+               --i;
+            }
+            stbsp__chk_cb_buf(1);
+         }
+
+         // copy trailing zeros
+         while (tz) {
+            stbsp__int32 i;
+            stbsp__cb_buf_clamp(i, tz);
+            tz -= i;
+            while (i) {
+               if ((((stbsp__uintptr)bf) & 3) == 0)
+                  break;
+               *bf++ = '0';
+               --i;
+            }
+            while (i >= 4) {
+               *(stbsp__uint32 *)bf = 0x30303030;
+               bf += 4;
+               i -= 4;
+            }
+            while (i) {
+               *bf++ = '0';
+               --i;
+            }
+            stbsp__chk_cb_buf(1);
+         }
+
+         // copy tail if there is one
+         sn = tail + 1;
+         while (tail[0]) {
+            stbsp__int32 i;
+            stbsp__cb_buf_clamp(i, tail[0]);
+            tail[0] -= (char)i;
+            while (i) {
+               *bf++ = *sn++;
+               --i;
+            }
+            stbsp__chk_cb_buf(1);
+         }
+
+         // handle the left justify
+         if (fl & STBSP__LEFTJUST)
+            if (fw > 0) {
+               while (fw) {
+                  stbsp__int32 i;
+                  stbsp__cb_buf_clamp(i, fw);
+                  fw -= i;
+                  while (i) {
+                     if ((((stbsp__uintptr)bf) & 3) == 0)
+                        break;
+                     *bf++ = ' ';
+                     --i;
+                  }
+                  while (i >= 4) {
+                     *(stbsp__uint32 *)bf = 0x20202020;
+                     bf += 4;
+                     i -= 4;
+                  }
+                  while (i--)
+                     *bf++ = ' ';
+                  stbsp__chk_cb_buf(1);
+               }
+            }
+         break;
+
+      default: // unknown, just copy code
+         s = num + STBSP__NUMSZ - 1;
+         *s = f[0];
+         l = 1;
+         fw = fl = 0;
+         lead[0] = 0;
+         tail[0] = 0;
+         pr = 0;
+         dp = 0;
+         cs = 0;
+         goto scopy;
+      }
+      ++f;
+   }
+endfmt:
+
+   if (!callback)
+      *bf = 0;
+   else
+      stbsp__flush_cb();
+
+done:
+   return tlen + (int)(bf - buf);
+}
+
+// cleanup
+#undef STBSP__LEFTJUST
+#undef STBSP__LEADINGPLUS
+#undef STBSP__LEADINGSPACE
+#undef STBSP__LEADING_0X
+#undef STBSP__LEADINGZERO
+#undef STBSP__INTMAX
+#undef STBSP__TRIPLET_COMMA
+#undef STBSP__NEGATIVE
+#undef STBSP__METRIC_SUFFIX
+#undef STBSP__NUMSZ
+#undef stbsp__chk_cb_bufL
+#undef stbsp__chk_cb_buf
+#undef stbsp__flush_cb
+#undef stbsp__cb_buf_clamp
+
+// ============================================================================
+//   wrapper functions
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(sprintf)(char *buf, char const *fmt, ...)
+{
+   int result;
+   va_list va;
+   va_start(va, fmt);
+   result = STB_SPRINTF_DECORATE(vsprintfcb)(0, 0, buf, fmt, va);
+   va_end(va);
+   return result;
+}
+
+typedef struct stbsp__context {
+   char *buf;
+   int count;
+   char tmp[STB_SPRINTF_MIN];
+} stbsp__context;
+
+static char *stbsp__clamp_callback(char *buf, void *user, int len)
+{
+   stbsp__context *c = (stbsp__context *)user;
+
+   if (len > c->count)
+      len = c->count;
+
+   if (len) {
+      if (buf != c->buf) {
+         char *s, *d, *se;
+         d = c->buf;
+         s = buf;
+         se = buf + len;
+         do {
+            *d++ = *s++;
+         } while (s < se);
+      }
+      c->buf += len;
+      c->count -= len;
+   }
+
+   if (c->count <= 0)
+      return 0;
+   return (c->count >= STB_SPRINTF_MIN) ? c->buf : c->tmp; // go direct into buffer if you can
+}
+
+static char * stbsp__count_clamp_callback( char * buf, void * user, int len )
+{
+   stbsp__context * c = (stbsp__context*)user;
+
+   c->count += len;
+   return c->tmp; // go direct into buffer if you can
+}
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsnprintf )( char * buf, int count, char const * fmt, va_list va )
+{
+   stbsp__context c;
+   int l;
+
+   if ( (count == 0) && !buf )
+   {
+      c.count = 0;
+
+      STB_SPRINTF_DECORATE( vsprintfcb )( stbsp__count_clamp_callback, &c, c.tmp, fmt, va );
+      l = c.count;
+   }
+   else
+   {
+      if ( count == 0 )
+         return 0;
+
+      c.buf = buf;
+      c.count = count;
+
+      STB_SPRINTF_DECORATE( vsprintfcb )( stbsp__clamp_callback, &c, stbsp__clamp_callback(0,&c,0), fmt, va );
+
+      // zero-terminate
+      l = (int)( c.buf - buf );
+      if ( l >= count ) // should never be greater, only equal (or less) than count
+         l = count - 1;
+      buf[l] = 0;
+   }
+
+   return l;
+}
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(snprintf)(char *buf, int count, char const *fmt, ...)
+{
+   int result;
+   va_list va;
+   va_start(va, fmt);
+
+   result = STB_SPRINTF_DECORATE(vsnprintf)(buf, count, fmt, va);
+   va_end(va);
+
+   return result;
+}
+
+STBSP__PUBLICDEF int STB_SPRINTF_DECORATE(vsprintf)(char *buf, char const *fmt, va_list va)
+{
+   return STB_SPRINTF_DECORATE(vsprintfcb)(0, 0, buf, fmt, va);
+}
+
+// =======================================================================
+//   low level float utility functions
+
+#ifndef STB_SPRINTF_NOFLOAT
+
+// copies d to bits w/ strict aliasing (this compiles to nothing on /Ox)
+#define STBSP__COPYFP(dest, src)                   \
+   {                                               \
+      int cn;                                      \
+      for (cn = 0; cn < 8; cn++)                   \
+         ((char *)&dest)[cn] = ((char *)&src)[cn]; \
+   }
+
+// get float info
+static stbsp__int32 stbsp__real_to_parts(stbsp__int64 *bits, stbsp__int32 *expo, double value)
+{
+   double d;
+   stbsp__int64 b = 0;
+
+   // load value and round at the frac_digits
+   d = value;
+
+   STBSP__COPYFP(b, d);
+
+   *bits = b & ((((stbsp__uint64)1) << 52) - 1);
+   *expo = (stbsp__int32)(((b >> 52) & 2047) - 1023);
+
+   return (stbsp__int32)((stbsp__uint64) b >> 63);
+}
+
+static double const stbsp__bot[23] = {
+   1e+000, 1e+001, 1e+002, 1e+003, 1e+004, 1e+005, 1e+006, 1e+007, 1e+008, 1e+009, 1e+010, 1e+011,
+   1e+012, 1e+013, 1e+014, 1e+015, 1e+016, 1e+017, 1e+018, 1e+019, 1e+020, 1e+021, 1e+022
+};
+static double const stbsp__negbot[22] = {
+   1e-001, 1e-002, 1e-003, 1e-004, 1e-005, 1e-006, 1e-007, 1e-008, 1e-009, 1e-010, 1e-011,
+   1e-012, 1e-013, 1e-014, 1e-015, 1e-016, 1e-017, 1e-018, 1e-019, 1e-020, 1e-021, 1e-022
+};
+static double const stbsp__negboterr[22] = {
+   -5.551115123125783e-018,  -2.0816681711721684e-019, -2.0816681711721686e-020, -4.7921736023859299e-021, -8.1803053914031305e-022, 4.5251888174113741e-023,
+   4.5251888174113739e-024,  -2.0922560830128471e-025, -6.2281591457779853e-026, -3.6432197315497743e-027, 6.0503030718060191e-028,  2.0113352370744385e-029,
+   -3.0373745563400371e-030, 1.1806906454401013e-032,  -7.7705399876661076e-032, 2.0902213275965398e-033,  -7.1542424054621921e-034, -7.1542424054621926e-035,
+   2.4754073164739869e-036,  5.4846728545790429e-037,  9.2462547772103625e-038,  -4.8596774326570872e-039
+};
+static double const stbsp__top[13] = {
+   1e+023, 1e+046, 1e+069, 1e+092, 1e+115, 1e+138, 1e+161, 1e+184, 1e+207, 1e+230, 1e+253, 1e+276, 1e+299
+};
+static double const stbsp__negtop[13] = {
+   1e-023, 1e-046, 1e-069, 1e-092, 1e-115, 1e-138, 1e-161, 1e-184, 1e-207, 1e-230, 1e-253, 1e-276, 1e-299
+};
+static double const stbsp__toperr[13] = {
+   8388608,
+   6.8601809640529717e+028,
+   -7.253143638152921e+052,
+   -4.3377296974619174e+075,
+   -1.5559416129466825e+098,
+   -3.2841562489204913e+121,
+   -3.7745893248228135e+144,
+   -1.7356668416969134e+167,
+   -3.8893577551088374e+190,
+   -9.9566444326005119e+213,
+   6.3641293062232429e+236,
+   -5.2069140800249813e+259,
+   -5.2504760255204387e+282
+};
+static double const stbsp__negtoperr[13] = {
+   3.9565301985100693e-040,  -2.299904345391321e-063,  3.6506201437945798e-086,  1.1875228833981544e-109,
+   -5.0644902316928607e-132, -6.7156837247865426e-155, -2.812077463003139e-178,  -5.7778912386589953e-201,
+   7.4997100559334532e-224,  -4.6439668915134491e-247, -6.3691100762962136e-270, -9.436808465446358e-293,
+   8.0970921678014997e-317
+};
+
+#if defined(_MSC_VER) && (_MSC_VER <= 1200)
+static stbsp__uint64 const stbsp__powten[20] = {
+   1,
+   10,
+   100,
+   1000,
+   10000,
+   100000,
+   1000000,
+   10000000,
+   100000000,
+   1000000000,
+   10000000000,
+   100000000000,
+   1000000000000,
+   10000000000000,
+   100000000000000,
+   1000000000000000,
+   10000000000000000,
+   100000000000000000,
+   1000000000000000000,
+   10000000000000000000U
+};
+#define stbsp__tento19th ((stbsp__uint64)1000000000000000000)
+#else
+static stbsp__uint64 const stbsp__powten[20] = {
+   1,
+   10,
+   100,
+   1000,
+   10000,
+   100000,
+   1000000,
+   10000000,
+   100000000,
+   1000000000,
+   10000000000ULL,
+   100000000000ULL,
+   1000000000000ULL,
+   10000000000000ULL,
+   100000000000000ULL,
+   1000000000000000ULL,
+   10000000000000000ULL,
+   100000000000000000ULL,
+   1000000000000000000ULL,
+   10000000000000000000ULL
+};
+#define stbsp__tento19th (1000000000000000000ULL)
+#endif
+
+#define stbsp__ddmulthi(oh, ol, xh, yh)                            \
+   {                                                               \
+      double ahi = 0, alo, bhi = 0, blo;                           \
+      stbsp__int64 bt;                                             \
+      oh = xh * yh;                                                \
+      STBSP__COPYFP(bt, xh);                                       \
+      bt &= ((~(stbsp__uint64)0) << 27);                           \
+      STBSP__COPYFP(ahi, bt);                                      \
+      alo = xh - ahi;                                              \
+      STBSP__COPYFP(bt, yh);                                       \
+      bt &= ((~(stbsp__uint64)0) << 27);                           \
+      STBSP__COPYFP(bhi, bt);                                      \
+      blo = yh - bhi;                                              \
+      ol = ((ahi * bhi - oh) + ahi * blo + alo * bhi) + alo * blo; \
+   }
+
+#define stbsp__ddtoS64(ob, xh, xl)          \
+   {                                        \
+      double ahi = 0, alo, vh, t;           \
+      ob = (stbsp__int64)ph;                \
+      vh = (double)ob;                      \
+      ahi = (xh - vh);                      \
+      t = (ahi - xh);                       \
+      alo = (xh - (ahi - t)) - (vh + t);    \
+      ob += (stbsp__int64)(ahi + alo + xl); \
+   }
+
+#define stbsp__ddrenorm(oh, ol) \
+   {                            \
+      double s;                 \
+      s = oh + ol;              \
+      ol = ol - (s - oh);       \
+      oh = s;                   \
+   }
+
+#define stbsp__ddmultlo(oh, ol, xh, xl, yh, yl) ol = ol + (xh * yl + xl * yh);
+
+#define stbsp__ddmultlos(oh, ol, xh, yl) ol = ol + (xh * yl);
+
+static void stbsp__raise_to_power10(double *ohi, double *olo, double d, stbsp__int32 power) // power can be -323 to +350
+{
+   double ph, pl;
+   if ((power >= 0) && (power <= 22)) {
+      stbsp__ddmulthi(ph, pl, d, stbsp__bot[power]);
+   } else {
+      stbsp__int32 e, et, eb;
+      double p2h, p2l;
+
+      e = power;
+      if (power < 0)
+         e = -e;
+      et = (e * 0x2c9) >> 14; /* %23 */
+      if (et > 13)
+         et = 13;
+      eb = e - (et * 23);
+
+      ph = d;
+      pl = 0.0;
+      if (power < 0) {
+         if (eb) {
+            --eb;
+            stbsp__ddmulthi(ph, pl, d, stbsp__negbot[eb]);
+            stbsp__ddmultlos(ph, pl, d, stbsp__negboterr[eb]);
+         }
+         if (et) {
+            stbsp__ddrenorm(ph, pl);
+            --et;
+            stbsp__ddmulthi(p2h, p2l, ph, stbsp__negtop[et]);
+            stbsp__ddmultlo(p2h, p2l, ph, pl, stbsp__negtop[et], stbsp__negtoperr[et]);
+            ph = p2h;
+            pl = p2l;
+         }
+      } else {
+         if (eb) {
+            e = eb;
+            if (eb > 22)
+               eb = 22;
+            e -= eb;
+            stbsp__ddmulthi(ph, pl, d, stbsp__bot[eb]);
+            if (e) {
+               stbsp__ddrenorm(ph, pl);
+               stbsp__ddmulthi(p2h, p2l, ph, stbsp__bot[e]);
+               stbsp__ddmultlos(p2h, p2l, stbsp__bot[e], pl);
+               ph = p2h;
+               pl = p2l;
+            }
+         }
+         if (et) {
+            stbsp__ddrenorm(ph, pl);
+            --et;
+            stbsp__ddmulthi(p2h, p2l, ph, stbsp__top[et]);
+            stbsp__ddmultlo(p2h, p2l, ph, pl, stbsp__top[et], stbsp__toperr[et]);
+            ph = p2h;
+            pl = p2l;
+         }
+      }
+   }
+   stbsp__ddrenorm(ph, pl);
+   *ohi = ph;
+   *olo = pl;
+}
+
+// given a float value, returns the significant bits in bits, and the position of the
+//   decimal point in decimal_pos.  +/-INF and NAN are specified by special values
+//   returned in the decimal_pos parameter.
+// frac_digits is absolute normally, but if you want from first significant digits (got %g and %e), or in 0x80000000
+static stbsp__int32 stbsp__real_to_str(char const **start, stbsp__uint32 *len, char *out, stbsp__int32 *decimal_pos, double value, stbsp__uint32 frac_digits)
+{
+   double d;
+   stbsp__int64 bits = 0;
+   stbsp__int32 expo, e, ng, tens;
+
+   d = value;
+   STBSP__COPYFP(bits, d);
+   expo = (stbsp__int32)((bits >> 52) & 2047);
+   ng = (stbsp__int32)((stbsp__uint64) bits >> 63);
+   if (ng)
+      d = -d;
+
+   if (expo == 2047) // is nan or inf?
+   {
+      *start = (bits & ((((stbsp__uint64)1) << 52) - 1)) ? "NaN" : "Inf";
+      *decimal_pos = STBSP__SPECIAL;
+      *len = 3;
+      return ng;
+   }
+
+   if (expo == 0) // is zero or denormal
+   {
+      if ((bits << 1) == 0) // do zero
+      {
+         *decimal_pos = 1;
+         *start = out;
+         out[0] = '0';
+         *len = 1;
+         return ng;
+      }
+      // find the right expo for denormals
+      {
+         stbsp__int64 v = ((stbsp__uint64)1) << 51;
+         while ((bits & v) == 0) {
+            --expo;
+            v >>= 1;
+         }
+      }
+   }
+
+   // find the decimal exponent as well as the decimal bits of the value
+   {
+      double ph, pl;
+
+      // log10 estimate - very specifically tweaked to hit or undershoot by no more than 1 of log10 of all expos 1..2046
+      tens = expo - 1023;
+      tens = (tens < 0) ? ((tens * 617) / 2048) : (((tens * 1233) / 4096) + 1);
+
+      // move the significant bits into position and stick them into an int
+      stbsp__raise_to_power10(&ph, &pl, d, 18 - tens);
+
+      // get full as much precision from double-double as possible
+      stbsp__ddtoS64(bits, ph, pl);
+
+      // check if we undershot
+      if (((stbsp__uint64)bits) >= stbsp__tento19th)
+         ++tens;
+   }
+
+   // now do the rounding in integer land
+   frac_digits = (frac_digits & 0x80000000) ? ((frac_digits & 0x7ffffff) + 1) : (tens + frac_digits);
+   if ((frac_digits < 24)) {
+      stbsp__uint32 dg = 1;
+      if ((stbsp__uint64)bits >= stbsp__powten[9])
+         dg = 10;
+      while ((stbsp__uint64)bits >= stbsp__powten[dg]) {
+         ++dg;
+         if (dg == 20)
+            goto noround;
+      }
+      if (frac_digits < dg) {
+         stbsp__uint64 r;
+         // add 0.5 at the right position and round
+         e = dg - frac_digits;
+         if ((stbsp__uint32)e >= 24)
+            goto noround;
+         r = stbsp__powten[e];
+         bits = bits + (r / 2);
+         if ((stbsp__uint64)bits >= stbsp__powten[dg])
+            ++tens;
+         bits /= r;
+      }
+   noround:;
+   }
+
+   // kill long trailing runs of zeros
+   if (bits) {
+      stbsp__uint32 n;
+      for (;;) {
+         if (bits <= 0xffffffff)
+            break;
+         if (bits % 1000)
+            goto donez;
+         bits /= 1000;
+      }
+      n = (stbsp__uint32)bits;
+      while ((n % 1000) == 0)
+         n /= 1000;
+      bits = n;
+   donez:;
+   }
+
+   // convert to string
+   out += 64;
+   e = 0;
+   for (;;) {
+      stbsp__uint32 n;
+      char *o = out - 8;
+      // do the conversion in chunks of U32s (avoid most 64-bit divides, worth it, constant denomiators be damned)
+      if (bits >= 100000000) {
+         n = (stbsp__uint32)(bits % 100000000);
+         bits /= 100000000;
+      } else {
+         n = (stbsp__uint32)bits;
+         bits = 0;
+      }
+      while (n) {
+         out -= 2;
+         *(stbsp__uint16 *)out = *(stbsp__uint16 *)&stbsp__digitpair.pair[(n % 100) * 2];
+         n /= 100;
+         e += 2;
+      }
+      if (bits == 0) {
+         if ((e) && (out[0] == '0')) {
+            ++out;
+            --e;
+         }
+         break;
+      }
+      while (out != o) {
+         *--out = '0';
+         ++e;
+      }
+   }
+
+   *decimal_pos = tens;
+   *start = out;
+   *len = e;
+   return ng;
+}
+
+#undef stbsp__ddmulthi
+#undef stbsp__ddrenorm
+#undef stbsp__ddmultlo
+#undef stbsp__ddmultlos
+#undef STBSP__SPECIAL
+#undef STBSP__COPYFP
+
+#endif // STB_SPRINTF_NOFLOAT
+
+// clean up
+#undef stbsp__uint16
+#undef stbsp__uint32
+#undef stbsp__int32
+#undef stbsp__uint64
+#undef stbsp__int64
+#undef STBSP__UNALIGNED
+
+#endif // STB_SPRINTF_IMPLEMENTATION
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/