Method prepare

samples/api/timestamp_queries/timestamp_queries.cpp:943–986

}

bool TimestampQueries::prepare(const vkb::ApplicationOptions &options)
{
	if (!ApiVulkanSample::prepare(options))
	{
		return false;
	}

	// Check if the selected device supports timestamps. A value of zero means no support.
	VkPhysicalDeviceLimits device_limits = get_device().get_gpu().get_properties().limits;
	if (device_limits.timestampPeriod == 0)
	{
		throw std::runtime_error{"The selected device does not support timestamp queries!"};
	}

	// Check if all queues support timestamp queries, if not we need to check on a per-queue basis
	if (!device_limits.timestampComputeAndGraphics)
	{
		// Check if the graphics queue used in this sample supports time stamps
		VkQueueFamilyProperties graphics_queue_family_properties = get_device().get_queue_by_flags(VK_QUEUE_GRAPHICS_BIT, 0).get_properties();
		if (graphics_queue_family_properties.timestampValidBits == 0)
		{
			throw std::runtime_error{"The selected graphics queue family does not support timestamp queries!"};
		}
	}

	camera.type = vkb::CameraType::LookAt;
	camera.set_position(glm::vec3(0.0f, 0.0f, -4.0f));
	camera.set_rotation(glm::vec3(0.0f, 180.0f, 0.0f));

	// Note: Using reversed depth-buffer for increased precision, so Znear and Zfar are flipped
	camera.set_perspective(60.0f, static_cast<float>(width) / static_cast<float>(height), 256.0f, 0.1f);

	load_assets();
	prepare_uniform_buffers();
	prepare_offscreen_buffer();
	setup_descriptor_set_layout();
	prepare_pipelines();
	setup_descriptor_pool();
	setup_descriptor_sets();
	prepare_time_stamp_queries();
	build_command_buffers();
	prepared = true;
	return true;
}

void TimestampQueries::render(float delta_time)
{