Add VK_EXT_astc_decode_mode support

The work was performed by collaboration of TheForge and Google. I am
merely splitting it up into smaller PRs and cleaning it up.

drivers/vulkan/rendering_device_driver_vulkan.cpp

@@ -497,6 +497,7 @@ Error RenderingDeviceDriverVulkan::_initialize_device_extensions() {
 	_register_requested_device_extension(VK_KHR_MAINTENANCE_2_EXTENSION_NAME, false);
 	_register_requested_device_extension(VK_EXT_PIPELINE_CREATION_CACHE_CONTROL_EXTENSION_NAME, false);
 	_register_requested_device_extension(VK_EXT_SUBGROUP_SIZE_CONTROL_EXTENSION_NAME, false);
+	_register_requested_device_extension(VK_EXT_ASTC_DECODE_MODE_EXTENSION_NAME, false);
 
 	if (Engine::get_singleton()->is_generate_spirv_debug_info_enabled()) {
 		_register_requested_device_extension(VK_KHR_SHADER_NON_SEMANTIC_INFO_EXTENSION_NAME, true);
@@ -1703,6 +1704,16 @@ RDD::TextureID RenderingDeviceDriverVulkan::texture_create(const TextureFormat &
 		image_view_create_info.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
 	}
 
+	VkImageViewASTCDecodeModeEXT decode_mode;
+	if (enabled_device_extension_names.has(VK_EXT_ASTC_DECODE_MODE_EXTENSION_NAME)) {
+		if (image_view_create_info.format >= VK_FORMAT_ASTC_4x4_UNORM_BLOCK && image_view_create_info.format <= VK_FORMAT_ASTC_12x12_SRGB_BLOCK) {
+			decode_mode.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_ASTC_DECODE_MODE_EXT;
+			decode_mode.pNext = nullptr;
+			decode_mode.decodeMode = VK_FORMAT_R8G8B8A8_UNORM;
+			image_view_create_info.pNext = &decode_mode;
+		}
+	}
+
 	VkImageView vk_image_view = VK_NULL_HANDLE;
 	err = vkCreateImageView(vk_device, &image_view_create_info, VKC::get_allocation_callbacks(VK_OBJECT_TYPE_IMAGE_VIEW), &vk_image_view);
 	if (err) {