gatling
1965 Ford Mustang Fastback from Wire Wheels Club, rendered in Gatling.
About
This is my toy path tracer I work on in my free time.
It is exposed as a Hydra render delegate and comes with a standalone that accepts Universal Scene Description (USD) files. It is cross-platform, GPU-accelerated, and supports MaterialX, MDL and UsdPreviewSurface materials.
Technically, gatling uses the MDL code generation backend of the MaterialX project to support and importance-sample complex BSDFs like the Autodesk Standard Surface or the glTF shading model. The MDL SDK then generates GLSL code which is compiled to SPIR-V for use in Vulkan. A compressed 8-wide BVH is used to speed up rendering, but hardware ray tracing will be used in the future.
Build
You need to
- install the Vulkan SDK
- download the MDL SDK 2022.0 binaries
- build USD 22.08 with MaterialX support
- have NASM 2.13+ or YASM 1.2.0+ in your PATH
Note: EXR export requires building USD with OpenImageIO support.
Do a recursive clone of the repository and set up a build folder:
git clone https://github.com/pablode/gatling --recursive
mkdir gatling/build && cd gatling/build
Pass following parameters in the CMake generation phase:
cmake .. -Wno-dev \
-DUSD_ROOT=<USD_INSTALL_DIR> \
-DMDL_ROOT=<MDL_INSTALL_DIR> \
-DCMAKE_INSTALL_PREFIX=<USD_INSTALL_DIR>/plugin/usd
-DCMAKE_BUILD_TYPE=Release
Note: If you're using MSVC, be sure to select a 64-bit generator.
Build the relevant targets and install the Hydra delegate to the USD plugin folder:
cmake --build . -j8 --target hdGatling gatling --config Release
cmake --install . --component hdGatling
Usage
Gatling can be used by every application which supports Hydra, either natively or through a plugin.
cekuhnen's Coffee Maker (CC-BY), slightly modified, rendered using Gatling inside Pixar's usdview tool.
A headless standalone is provided that accepts a USD file (.usd, .usda, .usdc, .usdz) as input. Make sure that there is a polygonal light source in the scene.
./bin/gatling <scene.usd> render.png \
--image-width 1200 \
--image-height 1200 \
--spp 1024 \
--max-bounces 8
Note: Disable the system's GPU watchdog or set an appropriate timeout value.
Outlook
Work in progress: texture support, material network patching, NEE/MIS.
License
Gatling is licensed under the GNU General Public License, as included in the LICENSE file.
Copyright (C) 2019-2022 Pablo Delgado Krämer
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
It contains code from the Ray Tracing Gems I book, which is MIT licensed and copyrighted:
- Copyright 2019 NVIDIA Corporation
It contains code from the MDL SDK, which is BSD licensed and copyrighted:
- Copyright (c) 2018-2021, NVIDIA CORPORATION. All rights reserved.