Vk: support 8-bit index types.

src/Magnum/Vk/Enums.cpp

@@ -46,7 +46,7 @@ constexpr VkPrimitiveTopology PrimitiveTopologyMapping[]{
 };
 
 constexpr VkIndexType IndexTypeMapping[]{
-    VkIndexType(~UnsignedInt{}),
+    VK_INDEX_TYPE_UINT8_EXT,
     VK_INDEX_TYPE_UINT16,
     VK_INDEX_TYPE_UINT32
 };

src/Magnum/Vk/Enums.h

@@ -58,10 +58,14 @@ MAGNUM_VK_EXPORT VkPrimitiveTopology vkPrimitiveTopology(Magnum::MeshPrimitive p
 /**
 @brief Check availability of a generic index type
 
-In particular, Vulkan doesn't support the @ref MeshIndexType::UnsignedByte
-type. Returns @cpp false @ce if Vulkan doesn't support such type, @cpp true @ce
+Returns @cpp false @ce if Vulkan doesn't support such type, @cpp true @ce
 otherwise. The @p type value is expected to be valid.
-@see @ref vkIndexType()
+
+@note Support of some types depends on presence of a particular Vulkan
+    extension. Such check is outside of the scope of this function and you are
+    expected to verify extension availability before using such type.
+
+@see @ref vkIndexType(), @vk_extension{EXT,index_type_uint8}
 */
 MAGNUM_VK_EXPORT bool hasVkIndexType(Magnum::MeshIndexType type);
 

src/Magnum/Vk/Test/EnumsTest.cpp

@@ -152,6 +152,9 @@ void EnumsTest::mapVkIndexType() {
 }
 
 void EnumsTest::mapVkIndexTypeUnsupported() {
+    #if 1
+    CORRADE_SKIP("All index formats are supported.");
+    #else
     CORRADE_VERIFY(!hasVkIndexType(Magnum::MeshIndexType::UnsignedByte));
     std::ostringstream out;
     {
@@ -160,6 +163,7 @@ void EnumsTest::mapVkIndexTypeUnsupported() {
     }
     CORRADE_COMPARE(out.str(),
         "Vk::vkIndexType(): unsupported type MeshIndexType::UnsignedByte\n");
+    #endif
 }
 
 void EnumsTest::mapVkIndexTypeInvalid() {

src/MagnumExternal/Vulkan/extensions.txt

@@ -25,6 +25,7 @@ extension KHR_storage_buffer_storage_class optional
 extension KHR_variable_pointers optional
 
 extension EXT_texture_compression_astc_hdr optional
+extension EXT_index_type_uint8 optional
 
 extension IMG_format_pvrtc optional
 

src/MagnumExternal/Vulkan/flextVk.h

@@ -246,6 +246,11 @@ extern "C" {
 #define VK_EXT_TEXTURE_COMPRESSION_ASTC_HDR_SPEC_VERSION 1
 #define VK_EXT_TEXTURE_COMPRESSION_ASTC_HDR_EXTENSION_NAME "VK_EXT_texture_compression_astc_hdr"
 
+/* VK_EXT_index_type_uint8 */
+
+#define VK_EXT_INDEX_TYPE_UINT8_SPEC_VERSION 1
+#define VK_EXT_INDEX_TYPE_UINT8_EXTENSION_NAME "VK_EXT_index_type_uint8"
+
 /* VK_IMG_format_pvrtc */
 
 #define VK_IMG_FORMAT_PVRTC_SPEC_VERSION 1
@@ -1404,7 +1409,8 @@ typedef enum {
     VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES,
     VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES,
     VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES,
-    VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXTURE_COMPRESSION_ASTC_HDR_FEATURES_EXT = 1000066000
+    VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXTURE_COMPRESSION_ASTC_HDR_FEATURES_EXT = 1000066000,
+    VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INDEX_TYPE_UINT8_FEATURES_EXT = 1000265000
 } VkStructureType;
 
 typedef enum {
@@ -3795,6 +3801,12 @@ typedef struct VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT {
     VkBool32               textureCompressionASTC_HDR;
 } VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT;
 
+typedef struct VkPhysicalDeviceIndexTypeUint8FeaturesEXT {
+    VkStructureType sType;
+    void*        pNext;
+    VkBool32                           indexTypeUint8;
+} VkPhysicalDeviceIndexTypeUint8FeaturesEXT;
+
 typedef struct VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures {
     VkStructureType sType;
     void*    pNext;