Foray Irradiance Cache

A simple world space irradiance cache implemented by @Firestar99

Short video showcase

Loosely based on DDGI, this irradiance cache uses simple point light-like probes that do not actually have any directionality. Instead, each Probe is placed on a world space 3D grid, which is backed by a 3D texture and most of the work has gone into sampling it correctly. This Project was build as part of a Master's Project worth 10 ETCS, and build upon the foray framework made by Joseph Heetel and Max as their master thesis.

If you're looking for code written by me, have a look at this readme.

Setup

git clone --recursive https://github.com/Vulkemp/foray-examples

--recursive clones the required submodule foray. Then import it into your IDE as a cmake project, or use cmake directly. Run the irradiance-cache binary for the main executable. Pre-build binaries are not available as the project is not setup to run outside a development environment.

Tested Build Environments

• Linux RADV
• Windows Nvidia
• sadly AMDVLK / AMD on Windows does not work, it segfaults inside the driver stack during raytrace pipeline initialization

Controls

• WASD: standard movement
• Shift/Ctrl: move up / down
• space: lock/unlock mouse to rotate camera
• C: clear irradiance cache
• T/G: previous / next Mode

Settings

• Traces per Frame: how many traces should be sent out per frame and probe, higher values trade worse performance for faster accumulation
• Accumulation Quality: adjusts accumulation factor to match traces per frame so the image quality remains mostly constant, higher values trade worse accumulation speed for better final image quality
• Accumulation Factor: the percentage by which the newly sampled values should be mixed with the previous values, higher values trade accumulation speed for better final image quality
• Normal Offset Factor: When sampling some geometry, the light will be sampled from the irradiance cache at the position the geometry was hit plus the normal of the geometry times this factor
• Alow skip IC: If a mode does not use the irradiance cache (IC) allow it to skip the accumulation stages, used to estimate overhead introduced by running stages doing nothing

Settings in code examples/irradiance-cache/src/IrradianceCacheApp.cpp:

• SCENE_FILE: path to the gltf scene file from the /data directory
• PROBE_DISTANCE: the distance between individual probes of the irradiance cache, with the size of the scene will determine the probe dimensions
• INVERT_BLIT_INSTEAD: If true, will invert the viewport when blitting. If false, will invert the scene while loading to -Y up.
• USE_CAMERA_FROM_GLTF: instead of an interactable camera load it from the gltf, useful for comparison against other renderers.