Fetch maximum available sample count for the device.

kondrak · kondrak · commit ad89b66a1d39 · 2018-07-19T22:09:09.000+02:00
diff --git a/code/29_multisampling.cpp b/code/29_multisampling.cpp
@@ -150,6 +150,8 @@ class HelloTriangleApplication {
     VkSurfaceKHR surface;
 
     VkPhysicalDevice physicalDevice = VK_NULL_HANDLE;
+    VkPhysicalDeviceProperties physicalDeviceProperties;
+    VkSampleCountFlagBits msaaSamples = VK_SAMPLE_COUNT_1_BIT;
     VkDevice device;
 
     VkQueue graphicsQueue;
@@ -406,6 +408,8 @@ class HelloTriangleApplication {
         for (const auto& device : devices) {
             if (isDeviceSuitable(device)) {
                 physicalDevice = device;
+                vkGetPhysicalDeviceProperties(physicalDevice, &physicalDeviceProperties);
+                msaaSamples = getMaxUsableSampleCount();
                 break;
             }
         }
@@ -922,6 +926,17 @@ class HelloTriangleApplication {
         endSingleTimeCommands(commandBuffer);
     }
 
+VkSampleCountFlagBits getMaxUsableSampleCount() {
+    VkSampleCountFlags counts = std::min(physicalDeviceProperties.limits.framebufferColorSampleCounts, physicalDeviceProperties.limits.framebufferDepthSampleCounts);
+    if (counts & VK_SAMPLE_COUNT_64_BIT) { return VK_SAMPLE_COUNT_64_BIT; }
+    if (counts & VK_SAMPLE_COUNT_32_BIT) { return VK_SAMPLE_COUNT_32_BIT; }
+    if (counts & VK_SAMPLE_COUNT_16_BIT) { return VK_SAMPLE_COUNT_16_BIT; }
+    if (counts & VK_SAMPLE_COUNT_8_BIT) { return VK_SAMPLE_COUNT_8_BIT; }
+    if (counts & VK_SAMPLE_COUNT_4_BIT) { return VK_SAMPLE_COUNT_4_BIT; }
+    if (counts & VK_SAMPLE_COUNT_2_BIT) { return VK_SAMPLE_COUNT_2_BIT; }
+    return VK_SAMPLE_COUNT_1_BIT;
+}
+
     void createTextureImageView() {
         textureImageView = createImageView(textureImage, VK_FORMAT_R8G8B8A8_UNORM, VK_IMAGE_ASPECT_COLOR_BIT, mipLevels);
     }
