From b82ab62675256f47f3476421fddcbd4cebf09b64 Mon Sep 17 00:00:00 2001
From: Jordan Halase <jordan@halase.me>
Date: Fri, 8 Nov 2019 10:08:18 -0600
Subject: Query surfaceCapabilities every new swapchain

---
 main.c | 46 +++++++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/main.c b/main.c
index 794a0dd..4a32cd0 100755
--- a/main.c
+++ b/main.c
@@ -223,7 +223,6 @@ struct RenderVulkan {
 	VkInstance			instance;
 	VkDebugReportCallbackEXT	debugCallback;
 	VkSurfaceKHR			surface;
-	VkSurfaceCapabilitiesKHR	surfaceCapabilities;
 	VkSurfaceFormatKHR		surfaceFormat;
 	VkPresentModeKHR		presentMode;
 	VkPhysicalDeviceProperties	deviceProperties;	// TODO: Make this a pointer. It's really big.
@@ -1242,15 +1241,9 @@ static bool isPresentModeSupported(const VkPresentModeKHR *const presentModes,
 /** Configure the surface for the currently opened device. */
 int rvkConfigureSurface(struct RenderVulkan *vk)
 {
-	VkSurfaceCapabilitiesKHR surfaceCapabilities;
 	VkSurfaceFormatKHR *surfaceFormats;
 	VkPresentModeKHR *presentModes;
 	VkResult result;
-	if ((result = vk->api->vkGetPhysicalDeviceSurfaceCapabilitiesKHR(
-					vk->physicalDevice, vk->surface, &surfaceCapabilities))) {
-		rvkSetErrMsg(vk, "Could not get surface capabilities: %d", result);
-		return -1;
-	}
 	uint32_t nFormats;
 	vk->api->vkGetPhysicalDeviceSurfaceFormatsKHR(vk->physicalDevice, vk->surface, &nFormats, NULL);
 	if (!nFormats) {
@@ -1317,21 +1310,45 @@ int rvkConfigureSurface(struct RenderVulkan *vk)
 	free(presentModes);
 	vk->presentMode = presentMode;
 	printf("Using present mode:\t\t`%s`\t(%d)\n", strPresentMode(presentMode), presentMode);
-	vk->surfaceCapabilities = surfaceCapabilities;
 	return 0;
 }
 
 static int rvkCreateRawSwapchain(struct RenderVulkan *vk, uint32_t width, uint32_t height)
 {
-	// FIXME: We actually need a new surfaceCapabilities for every new swapchain.
-	//width = CLAMP(width, vk->surfaceCapabilities.minImageExtent.width, vk->surfaceCapabilities.maxImageExtent.width);
-	//height = CLAMP(height, vk->surfaceCapabilities.minImageExtent.height, vk->surfaceCapabilities.maxImageExtent.height);
+	VkSurfaceCapabilitiesKHR surfaceCapabilities;
+	VkResult result;
+	if ((result = vk->api->vkGetPhysicalDeviceSurfaceCapabilitiesKHR(
+					vk->physicalDevice, vk->surface, &surfaceCapabilities))) {
+		rvkSetErrMsg(vk, "Could not get surface capabilities: %d", result);
+		return -1;
+	}
+
+	/* The current window size isn't always equivalent to the Vulkan surface
+	 * drawable size, which can be observed when resizing the window on the
+	 * fly with some devices and drivers. I suspect this is the result of a
+	 * race condition between the window size and the drawable size, with
+	 * the reported window size lagging behind the drawable size, or that
+	 * the surface is proactively resized internally by the Vulkan driver
+	 * before the window system finalizes this new size.
+	 *
+	 * This has been observed on multiple platforms and seems inherent to
+	 * the window system.
+	 *
+	 * Nonetheless, clamping the returned window size to the minimum and
+	 * maximum surface capabilities seems to fix the problem completely.
+	 *
+	 * Furthermore, it may be possible that we don't even need to query the
+	 * window system for its size at all, and could possibly simply use the
+	 * `currentExtent` of the `VkSurfaceCapabilitiesKHR`.
+	 */
+	width = CLAMP(width, surfaceCapabilities.minImageExtent.width, surfaceCapabilities.maxImageExtent.width);
+	height = CLAMP(height, surfaceCapabilities.minImageExtent.height, surfaceCapabilities.maxImageExtent.height);
 
 	vk->swapchain->extent.width = width;
 	vk->swapchain->extent.height = height;
 
-	vk->swapchain->nImages = vk->surfaceCapabilities.minImageCount;
-	//vk->swapchain->nImages = vk->surfaceCapabilities.maxImageCount;
+	vk->swapchain->nImages = surfaceCapabilities.minImageCount;
+	//vk->swapchain->nImages = surfaceCapabilities.maxImageCount;
 
 	VkSwapchainCreateInfoKHR createInfo = { 0 };
 	createInfo.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
@@ -1342,14 +1359,13 @@ static int rvkCreateRawSwapchain(struct RenderVulkan *vk, uint32_t width, uint32
 	createInfo.imageArrayLayers = 1;
 	createInfo.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
 	createInfo.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
-	createInfo.preTransform = vk->surfaceCapabilities.currentTransform;
+	createInfo.preTransform = surfaceCapabilities.currentTransform;
 	createInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
 	createInfo.presentMode = vk->presentMode;
 	createInfo.clipped = VK_TRUE;
 	if (vk->swapchain->old) {
 		createInfo.oldSwapchain = vk->swapchain->old->rawSwapchain;
 	}
-	VkResult result;
 	if ((result = vk->dev->vkCreateSwapchainKHR(vk->device, &createInfo, ALLOC_VK, &vk->swapchain->rawSwapchain))) {
 		rvkSetErrMsg(vk, "Could not create swapchain: %d", result);
 		return -1;
-- 
cgit v1.2.1