Method buffer_get_data_async

servers/rendering/rendering_device.cpp:694–778

}

Error RenderingDevice::buffer_get_data_async(RID p_buffer, const Callable &p_callback, uint32_t p_offset, uint32_t p_size) {
	ERR_RENDER_THREAD_GUARD_V(ERR_UNAVAILABLE);

	Buffer *buffer = _get_buffer_from_owner(p_buffer);
	if (buffer == nullptr) {
		ERR_FAIL_V_MSG(ERR_INVALID_PARAMETER, "Buffer is either invalid or this type of buffer can't be retrieved.");
	}

	if (p_size == 0) {
		p_size = buffer->size;
	}

	ERR_FAIL_COND_V_MSG(p_size + p_offset > buffer->size, ERR_INVALID_PARAMETER, "Size is larger than the buffer.");
	ERR_FAIL_COND_V_MSG(!p_callback.is_valid(), ERR_INVALID_PARAMETER, "Callback must be valid.");

	_check_transfer_worker_buffer(buffer);

	BufferGetDataRequest get_data_request;
	get_data_request.callback = p_callback;
	get_data_request.frame_local_index = frames[frame].download_buffer_copy_regions.size();
	get_data_request.size = p_size;

	const uint32_t required_align = 32;
	uint32_t block_write_offset;
	uint32_t block_write_amount;
	StagingRequiredAction required_action;
	uint32_t to_submit = p_size;
	uint32_t submit_from = 0;
	while (to_submit > 0) {
		Error err = _staging_buffer_allocate(download_staging_buffers, MIN(to_submit, download_staging_buffers.block_size), required_align, block_write_offset, block_write_amount, required_action);
		if (err) {
			return err;
		}

		const bool flush_frames = (get_data_request.frame_local_count > 0) && required_action == STAGING_REQUIRED_ACTION_FLUSH_AND_STALL_ALL;
		if (flush_frames) {
			if (_buffer_make_mutable(buffer, p_buffer)) {
				// The buffer must be mutable to be used as a copy source.
				draw_graph.add_synchronization();
			}

			for (uint32_t i = 0; i < get_data_request.frame_local_count; i++) {
				uint32_t local_index = get_data_request.frame_local_index + i;
				draw_graph.add_buffer_get_data(buffer->driver_id, buffer->draw_tracker, frames[frame].download_buffer_staging_buffers[local_index], frames[frame].download_buffer_copy_regions[local_index]);
			}
		}

		_staging_buffer_execute_required_action(download_staging_buffers, required_action);

		if (flush_frames) {
			get_data_request.frame_local_count = 0;
			get_data_request.frame_local_index = frames[frame].download_buffer_copy_regions.size();
		}

		RDD::BufferCopyRegion region;
		region.src_offset = submit_from + p_offset;
		region.dst_offset = block_write_offset;
		region.size = block_write_amount;