Add buffer_copy method to RenderingDevice

drivers/vulkan/rendering_device_vulkan.cpp

@@ -5905,6 +5905,64 @@ void RenderingDeviceVulkan::uniform_set_set_invalidation_callback(RID p_uniform_
 	us->invalidated_callback_userdata = p_userdata;
 }
 
+Error RenderingDeviceVulkan::buffer_copy(RID p_src_buffer, RID p_dst_buffer, uint32_t p_src_offset, uint32_t p_dst_offset, uint32_t p_size, BitField<BarrierMask> p_post_barrier) {
+	_THREAD_SAFE_METHOD_
+
+	ERR_FAIL_COND_V_MSG(draw_list, ERR_INVALID_PARAMETER,
+			"Copying buffers is forbidden during creation of a draw list");
+	ERR_FAIL_COND_V_MSG(compute_list, ERR_INVALID_PARAMETER,
+			"Copying buffers is forbidden during creation of a compute list");
+
+	// This method assumes the barriers have been pushed prior to being called, therefore no barriers are pushed
+	// for the source or destination buffers before performing the copy. These masks are effectively ignored.
+	VkPipelineShaderStageCreateFlags src_stage_mask = 0;
+	VkAccessFlags src_access_mask = 0;
+	Buffer *src_buffer = _get_buffer_from_owner(p_src_buffer, src_stage_mask, src_access_mask, BARRIER_MASK_NO_BARRIER);
+	if (!src_buffer) {
+		ERR_FAIL_V_MSG(ERR_INVALID_PARAMETER, "Source buffer argument is not a valid buffer of any type.");
+	}
+
+	VkPipelineStageFlags dst_stage_mask = 0;
+	VkAccessFlags dst_access = 0;
+	if (p_post_barrier.has_flag(BARRIER_MASK_TRANSFER)) {
+		// If the post barrier mask defines it, we indicate the destination buffer will require a barrier with these flags set
+		// after the copy command is queued.
+		dst_stage_mask = VK_PIPELINE_STAGE_TRANSFER_BIT;
+		dst_access = VK_ACCESS_TRANSFER_WRITE_BIT;
+	}
+
+	Buffer *dst_buffer = _get_buffer_from_owner(p_dst_buffer, dst_stage_mask, dst_access, p_post_barrier);
+	if (!dst_buffer) {
+		ERR_FAIL_V_MSG(ERR_INVALID_PARAMETER, "Destination buffer argument is not a valid buffer of any type.");
+	}
+
+	// Validate the copy's dimensions for both buffers.
+	ERR_FAIL_COND_V_MSG((p_size + p_src_offset) > src_buffer->size, ERR_INVALID_PARAMETER, "Size is larger than the source buffer.");
+	ERR_FAIL_COND_V_MSG((p_size + p_dst_offset) > dst_buffer->size, ERR_INVALID_PARAMETER, "Size is larger than the destination buffer.");
+
+	// Perform the copy.
+	VkBufferCopy region;
+	region.srcOffset = p_src_offset;
+	region.dstOffset = p_dst_offset;
+	region.size = p_size;
+	vkCmdCopyBuffer(frames[frame].draw_command_buffer, src_buffer->buffer, dst_buffer->buffer, 1, &region);
+
+#ifdef FORCE_FULL_BARRIER
+	_full_barrier(true);
+#else
+	if (dst_stage_mask == 0) {
+		dst_stage_mask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
+	}
+
+	// As indicated by the post barrier mask, push a new barrier.
+	if (p_post_barrier != RD::BARRIER_MASK_NO_BARRIER) {
+		_buffer_memory_barrier(dst_buffer->buffer, p_dst_offset, p_size, VK_PIPELINE_STAGE_TRANSFER_BIT, dst_stage_mask, VK_ACCESS_TRANSFER_WRITE_BIT, dst_access, true);
+	}
+#endif
+
+	return OK;
+}
+
 Error RenderingDeviceVulkan::buffer_update(RID p_buffer, uint32_t p_offset, uint32_t p_size, const void *p_data, BitField<BarrierMask> p_post_barrier) {
 	_THREAD_SAFE_METHOD_
 

drivers/vulkan/rendering_device_vulkan.h

@@ -1152,6 +1152,7 @@ class RenderingDeviceVulkan : public RenderingDevice {
 	virtual bool uniform_set_is_valid(RID p_uniform_set);
 	virtual void uniform_set_set_invalidation_callback(RID p_uniform_set, InvalidationCallback p_callback, void *p_userdata);
 
+	virtual Error buffer_copy(RID p_src_buffer, RID p_dst_buffer, uint32_t p_src_offset, uint32_t p_dst_offset, uint32_t p_size, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS);
 	virtual Error buffer_update(RID p_buffer, uint32_t p_offset, uint32_t p_size, const void *p_data, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS); // Works for any buffer.
 	virtual Error buffer_clear(RID p_buffer, uint32_t p_offset, uint32_t p_size, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS);
 	virtual Vector<uint8_t> buffer_get_data(RID p_buffer, uint32_t p_offset = 0, uint32_t p_size = 0);

servers/rendering/renderer_rd/storage_rd/mesh_storage.cpp

@@ -1309,13 +1309,10 @@ void MeshStorage::_multimesh_enable_motion_vectors(MultiMesh *multimesh) {
 	RID new_buffer = RD::get_singleton()->storage_buffer_create(new_buffer_size);
 
 	if (multimesh->buffer_set && multimesh->data_cache.is_empty()) {
-		// If the buffer was set but there's no data cached in the CPU, we must download it from the GPU and
-		// upload it because RD does not provide a way to copy the buffer directly yet.
+		// If the buffer was set but there's no data cached in the CPU, we copy the buffer directly on the GPU.
 		RD::get_singleton()->barrier();
-		Vector<uint8_t> buffer_data = RD::get_singleton()->buffer_get_data(multimesh->buffer);
-		ERR_FAIL_COND(buffer_data.size() != int(buffer_size));
-		RD::get_singleton()->buffer_update(new_buffer, 0, buffer_size, buffer_data.ptr(), RD::BARRIER_MASK_NO_BARRIER);
-		RD::get_singleton()->buffer_update(new_buffer, buffer_size, buffer_size, buffer_data.ptr());
+		RD::get_singleton()->buffer_copy(multimesh->buffer, new_buffer, 0, 0, buffer_size, RD::BARRIER_MASK_NO_BARRIER);
+		RD::get_singleton()->buffer_copy(multimesh->buffer, new_buffer, 0, buffer_size, buffer_size);
 	} else if (!multimesh->data_cache.is_empty()) {
 		// Simply upload the data cached in the CPU, which should already be doubled in size.
 		ERR_FAIL_COND(multimesh->data_cache.size() != int(new_buffer_size));

servers/rendering/rendering_device.h

@@ -840,6 +840,7 @@ class RenderingDevice : public Object {
 	virtual bool uniform_set_is_valid(RID p_uniform_set) = 0;
 	virtual void uniform_set_set_invalidation_callback(RID p_uniform_set, InvalidationCallback p_callback, void *p_userdata) = 0;
 
+	virtual Error buffer_copy(RID p_src_buffer, RID p_dst_buffer, uint32_t p_src_offset, uint32_t p_dst_offset, uint32_t p_size, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS) = 0;
 	virtual Error buffer_update(RID p_buffer, uint32_t p_offset, uint32_t p_size, const void *p_data, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS) = 0;
 	virtual Error buffer_clear(RID p_buffer, uint32_t p_offset, uint32_t p_size, BitField<BarrierMask> p_post_barrier = BARRIER_MASK_ALL_BARRIERS) = 0;
 	virtual Vector<uint8_t> buffer_get_data(RID p_buffer, uint32_t p_offset = 0, uint32_t p_size = 0) = 0; // This causes stall, only use to retrieve large buffers for saving.