Hollow;TerrainSystem (Prototype)

This project is a proof-of-concept for GPU driven terrain system made for Unity engine. This is NOT a production ready package, just a demo project.

Supports Unity 2022.3, built-in render pipeline.

Features

• Adaptive Virtual Texturing
  • Uses job system for multithreaded feedback analysis & page update
  • Cache textures are BC1 compressed
• GPU driven LOD selection
  • LOD is controlled by pixel-error metric similar to built-in Unity terrain
  • Stitches vertices between terrain patches (stitching between terrain tiles coming later)
• GPU driven LOD quad-tree generation as well
  • 6ms to recompute 2049x2049 terrain LOD tree
• GPU driven cross-terrain tile painting, doesn't rely on CPU readback
  • Painting remains responsive no matter the brush size
• Simple Undo/Redo system for render textures integrated with Unity editor
• Splat mapping using texture arrays
  • 1 draw call instead of multi-pass
  • Supports blending based on heightmap
  • Includes tools that combines multiple textures into Tex2DArray on import with limited auto-reformat functionality
  • Triplanar mapping
• Terrain works with scene picking (no outline though)

Anyway if you want to poke at it, go to TestScene.unity. For render loop implementation check PhotoTerrainBuiltInCamera code.

Known Issues

• Shadows suck!
• Terrain isn't visible when viewing scene in wireframe or looking at camera preview in scene window
• AMD GPUs might act funny with virtual texture. I think I fixed it, but it may still be there
• When using brush, first stroke might randomly produce incorrect result

Notes

• When using brushes, use alt+lmb and move mouse up/down to change opacity, left/right to change size. Alt + scroll will rotate the brush.
• If you modify material palette and want to make a build, use context menu -> "Create Texture Array" on palette asset. Texture arrays can't be created at runtime

3rd party

• 'Betsy' GPU compressor
• meshoptimizer
• LightProbeUtility by keijiro
• Unity's Terrain Tools (Icons)
• Terrain Sample Asset Pack (Terrain textures)

References

• GPUDrivenTerrainLearn
• Terrain Rendering in Far Cry 5
• Landscape creation and rendering in REDengine 3
• Boots on the Ground: The Terrain of Call of Duty
• Large Scale Terrain Rendering in Call of Duty
• J.M.P. van Waveren - Software Virtual Textures
• Adaptive Virtual Texture Rendering in Far Cry 4
• Virtual Texturing - Andreas Neu
• Normal Mapping for a Triplanar Shader - Ben Golus