Function queueScreenshot

layersvt/screenshot.cpp:1160–1203

This function issues commands to copy/convert the swapchain image from whatever compatible format the swapchain image uses to a single format (VK_FORMAT_R8G8B8A8_UNORM) so that the converted result can be easily written to a PPM file. Error handling: If there is a problem, this function should silently fail without affecting the Present operation going on in the caller. The numerous debug asserts

//
// Returns true if successfull, false otherwise.
static bool queueScreenshot(ScreenshotQueueData &data, VkImage image1, const VkPresentInfoKHR *presentInfo) {
    PROFILE("screenshot.queue");
    if (data.device == VK_NULL_HANDLE) {
        if (!prepareScreenshotData(data, image1)) {
            assert(false);
            return false;
        }
    } else {
        if (data.pTableDevice->ResetFences(data.device, 1, &data.fence) != VK_SUCCESS) {
            assert(false);
            return false;
        }
    }

    VkSubmitInfo submitInfo;
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.pNext = NULL;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &data.commandBuffer;
    VkPipelineStageFlags layerWaitStage = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
    submitInfo.pWaitDstStageMask = &layerWaitStage;
    submitInfo.pWaitSemaphores = presentInfo->pWaitSemaphores;
    submitInfo.waitSemaphoreCount = presentInfo->waitSemaphoreCount;
    submitInfo.signalSemaphoreCount = 1;
    submitInfo.pSignalSemaphores = &data.semaphore;

    VkQueue queue = getQueueForScreenshot(data.device);
    if (!queue) {
#ifdef ANDROID
        __android_log_print(ANDROID_LOG_ERROR, "screenshot", "Failure - capable queue not found\n");
#else
        fprintf(stderr, "screenshot: Could not find a capable queue\n");
#endif
        return false;
    }

    VkuDeviceDispatchTable *pTableQueue =
        get_dispatch_info(static_cast<VkDevice>(static_cast<void *>(queue)))->device_dispatch_table;

    VkResult err = pTableQueue->QueueSubmit(queue, 1, &submitInfo, data.fence);
    assert(!err);

    return true;
}

// Save an image to a PPM image file.
// Returns true if file is successfully written, false otherwise.