Awesome

VK_NV_inherited_viewport_scissor Sample

2020's take on the classic "fountain of exploding objects" demo; objects are spawned at the origin with a random velocity and fall down to their doom.

The primary purpose of this sample is to demonstrate how to integrate VK_NV_inherited_viewport_scissor as an <i>optional</i> extension. This extension enables subpass secondary command buffers to inherit viewport/scissor state from the calling primary command buffer (or another secondary command buffer).

The sample draws the same scene to four viewports on screen, with the actual drawing done by secondary command buffers re-used across frames. This is made possible by indirect draw commands, which allow the secondary command buffers to adapt to dynamically-changing object counts and positions. With the extension enabled, the sample is able to use the same secondary command buffer for all 4 viewports, and skip re-recording them even when the window or viewports are resized.

For a simple renderer like this, the CPU time saved by not re-recording the command buffer is likely negligible, but the techniques can be extended to more complicated renderers, where the savings can be substantial.

TUTORIAL LINK

Dependencies

The optional VK_NV_inherited_viewport_scissor extension is available in new NVIDIA Vulkan Drivers for Windows 10 or Linux. The header file for the extension is included in this repository, so you do not need to update your Vulkan SDK.

However, validation layer support for the extension requires at least v1.2.178. As of 2021-07-05, this is included in the latest official Vulkan SDK Package.

Build and Run

Clone https://github.com/nvpro-samples/nvpro_core.git next to this repository (or pull latest master if you already have it)

mkdir build && cd build && cmake .. # Or use CMake GUI

If there are missing dependencies (e.g. glfw), run git submodule update --init --recursive --checkout --force in the nvpro_core repository.

Then start the generated .sln in VS or run make -j.

Run vk_inherited_viewport or ../../bin_x64/Release/vk_inherited_viewport.exe

You are advised not to run the debug build unless you have the required validation layers.

LICENSE

Copyright 2021 NVIDIA CORPORATION. Released under Apache License, Version 2.0. See "LICENSE" file for details.