Rendu Documentation
Rendu is a rendering engine designed for experimentation. The computer graphics academic and industrial litterature is full of interesting techniques and approaches than can be cumbersome to implement without some basic building blocks. This project aims to provide those building blocks, along with examples of interesting methods or papers. It also contains more general demo applications, such as a small snake game or a gamepad configurator.
Rendu requires OpenGL 4 and builds on macOS (main test machine), Windows (regular testing) and Linux. After cloning the Rendu repository, see the Building section to get the engine running! You can also check the full documentation.
Basic resources to run each project are included in this repository, but you can download many additional scenes from an auxiliary repository for some of the applications.
Projects
Applications
| Name | Description |
|---|---|
| Deferred Physically based rendering |  Real-time rendering of a scene with 'physically-based' materials (GGX BRDF introduced in Microfacet Models for Refraction through Rough Surfaces, Walter et al., 2007), using deferred rendering and an HDR pipeline with bloom and SSAO. |
| Path Tracer |  Offline unidirectional path tracing for diffuse textured materials. Supports stratified sampling, jittering, a form of next event estimation, environment lighting contribution. Relies on a raycaster with a BVH for fast intersection queries against triangular meshes. Comes with an interactive viewer where the BVH levels can be displayed, and the camera placed for an offline rendering. |
| Image Filtering |  Apply filters to an image, such as gaussian blur, approximate flood-fill (Jump Flooding in GPU with Applications to Voronoi Diagram and Distance Transform, Rong et al., 2006) and poisson filling (Convolution Pyramids, Farbman et al., 2011), etc. |
| Atmospheric scattering |  Realistic atmosphere rendering with Rayleigh and Mie scattering (Precomputed Atmospheric Scattering, Bruneton et al., 2008). |
| Snake Game |  A basic game of snake, demonstrating game menus, player state, batched rendering. |
Tools
| Name | Description |
|---|---|
| Image viewer |  Basic image viewer and editor for LDR and HDR images, supporting rotations, channels toggling, color picking. |
| BRDF Estimator |  Compute data for image-based lighting from an environment map: pre-convolved irradiance, BRDF look-up table, ambient lighting spherical harmonics decomposition. |
| Controller mapper |  Interface to create and edit controller button/stick mappings. |
| Shader validator |  Perform per-shader compilation against the GPU driver and reports errors in an IDE-compatible fashion. |
| Atmospheric scattering preprocess |  Compute the atmosphere coefficients look-up table for the Atmospheric Scattering project. |
| Playground |  Simple application setting up a rendering context for small experimentations. |
Building
This project use premake5 (premake.github.io) for generating the workspace and projects files.
After cloning Rendu, move to the root of the repository and run
premake5.exe [vs2017 | xcode | make | ...]
To generate the desired workspace in the build directory.
The documentation (access it at docs/index.html) relies on Doxygen being installed. Generate it with
premake5 docs
You can clean the build directory with
premake5 clean
All non-system dependencies are compiled directly along with the projects. The only exception is gtk3 on Linux.
Features
On a more detailed level, here are the main features you will find in Rendu.
- Window and graphics context setup.
- GPU objects creation and management (shaders, textures, buffers).
- Resources handling and packing.
- Shader validation at compilation time.
- Input management with controllers support.
- 3D rendering, including per-fragment shading, normal maps, parallax mapping.
- Lights: omni/spots/directional lights, variance shadow mapping.
- Environment lighting, using cubemaps, preconvolved irradiance maps and spherical harmonics.
- Linear lighting pipeline, with HDR, bloom, tonemapping and gamma correction.
- Screen space techniques: antialiasing, ambient occlusion.
- Image processing techniques, such as fast gaussian blur, Poisson inpainting, flood filling.
- 2D interface rendering (buttons, checkboxes) with support for font distance fields.
- A raycaster CPU implementation using a bounding volume hierarchy.
Planned
I would like to add some additional features to Rendu in the near future, mainly to get a better grasp of some techniques and allow for more experimentations.
- Local light probes for reflections, parallax correction.
- Temporal Antialiasing with reprojection and clamping.
- Screen-space reflections and shadows (raymarching against the depth buffer).
- Rendering of a terrain and water using a procedural approach (Perlin/Worley/Fractal noise, maybe tesselation).
- Particle effects (updated on the GPU).
- Volumetric effects, such as godrays and lit fog.
- Support interesting controllers (MIDI controllers, PS4 light bar and touchpad,...)
On a more down-to-earth level, some engineering tasks could also help improve the engine.
- Cleanup the way materials are handled right now.
- Real-time cube maps could be rendered in multiple calls after culling objects, instead of layered rendering.
- Abstract interactions with OpenGL and/or move to Vulkan.