LUMINA HDRP: True Voxel based Real time Global Illumination

Features:

- Fully real time, true Global Illumination system for the High Definition Rendering Pipeline.

- Voxel based solution (Not based on screen space) for zero local change of the lighting or flickering as the camera rotates and moves around.

- Creates a volume representation of the scene, which can be used as a style as well, this aspect will be work in progress for offering a special stylistic voxel look of the whole scene directly.

- Grabs color from both main color and object textures, for maximum realism.

- Ambient Occlusion embedded to the GI solution.

- Multiple optimizations factors (Full or Half resolution rendering of the effect - Low, High and Insane voxel resolution options - Cones number and lighting calculations steps - Update per a number of seconds or per distance travelled)

- Easy setup, a single script on camera configures the pipeline and the effect directly, minor changes are required in the renderers after that setup, described in the manual and the Video Tutorial (URP) - LUMINA Video Tutorial (HDRP).

- Supports big number of mesh shaped lights, mesh lights are configured with emissive color and texture, set HDR color powerto zero to stop the effect, above zero to cast light and the main color alpha to further control the light power.

Roadmap (Some of the entries are TBD):

- Support point and spot lights, though those can already be emulated by the mesh lighting system.

- Finalize some experimental aspects like the integrated temporal AA.

- Create a version of the system that will support cascades.

- Create combined demos of LUMINA asset together with Sky Master ULTIMATE HDRP Weather system, for a complete atmospheric emulation showcase.

IMPORTANT: The real time global illumination problem is generally a very complex and hard one, thus there is some considerations currently on the system, which will be mentioned here.

The system uses Geometry shaders to calculate the voxelized space, thus is not compatible with any hardware that does not support Geometry Shaders, e.g. Mac PCs.

The system is ideal for smaller spaces, where the voxelized space can be calculated only once and possibly be recalculated on the fly every time entering a new room, this is the ideal use scenario.

The system can be used in realtime for infinite worlds with constant space voxelization and there is two ways to optimize, update the voxelization per distance or per time, or both together, keep in mind can be more taxing to get a smoother volume recalculation result in run time.

Update per time will showcase a gap in lighting in moving objects, so is best used for very fast or slow moving items.

The system supports only sun light source and local light sources through emissive materials, there is no direct support for spot and point lights casting GI.

The system uses the Standard Pipeline to render the scene voxelized volume. The rendering is then diverted to the HDRP. Also the true transparent materials are not included in the GI solution, this aspect is work in progress and TBD if can be addressed in later updates.

A cascaded version and integration with volumetric lighting are also in the works, those are not guaranteed to be finally included in the asset and depend on a lot of factors, main one is reception of the system and reviews and second is feasibility and usefulness assessment.

The system requires Unity 2021.3 LTS and above with HDRP renderer and due to the complexity and technical methods supports only LTS versions and has not been tested in Unity 2022. Also does not support VR, Mobile, Mac because uses Geometry Shaders, WebGL and Consoles.

LUMINA HDRP due to the extra HDRP load requires DX12 to function in all GPUs due to the swapchain Unity bug in DX11.