Added ETC2 and ASTC texture variants (Refs #174)

texturecubemap/texturecubemap.cpp

@@ -299,6 +299,31 @@ public:
 		vkDestroyBuffer(device, stagingBuffer, nullptr);
 	}
 
+	void loadTextures()
+	{
+		// Vulkan core supports three different compressed texture formats
+		// As the support differs between implemementations we need to check device features and select a proper format and file
+		std::string filename;
+		VkFormat format;
+		if (deviceFeatures.textureCompressionBC) {
+			filename = "cubemap_yokohama_bc3_unorm.ktx";
+			format = VK_FORMAT_BC2_UNORM_BLOCK;
+		}
+		else if (deviceFeatures.textureCompressionASTC_LDR) {
+			filename = "cubemap_yokohama_astc_8x8_unorm.ktx";
+			format = VK_FORMAT_ASTC_8x8_UNORM_BLOCK;
+		}
+		else if (deviceFeatures.textureCompressionETC2) {
+			filename = "cubemap_yokohama_etc2_unorm.ktx";
+			format = VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK;
+		}
+		else {
+			vks::tools::exitFatal("Device does not support any compressed texture format!", "Error");
+		}
+
+		loadCubemap(getAssetPath() + "textures/" + filename, format, false);
+	}
+
 	void reBuildCommandBuffers()
 	{
 		if (!checkCommandBuffers())
@@ -676,13 +701,10 @@ public:
 	void prepare()
 	{
 		VulkanExampleBase::prepare();
+		loadTextures();
 		loadMeshes();
 		setupVertexDescriptions();
 		prepareUniformBuffers();
-		loadCubemap(
-			getAssetPath() + "textures/cubemap_yokohama.ktx",
-			VK_FORMAT_BC3_UNORM_BLOCK,
-			false);
 		setupDescriptorSetLayout();
 		preparePipelines();
 		setupDescriptorPool();