# Voxel Raymarching

## Summary
GPU accelerated approach to visualize volumetic data (3D textures). Based on a discrete traversal over data to find a collision with internal volume.


## Reference

### ["Minecraft" on GPU](https://www.shadertoy.com/view/MtcGDH)
Very close example with rich post effects (fancy lighting, ambient occlusions)


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### [Branchless Voxel Raymarching](https://www.shadertoy.com/view/4dX3zl)
Most perfomant approach (as I know) achived by changing if-else blocks on pure math.


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### [Raymarching in Unity](https://github.com/hecomi/uRaymarching)
Open-source raymarching framework for Unity supports Standard shader and tightly integrated with Unity's rendering pipeline

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### [Improvement branchless](https://www.shadertoy.com/view/MdBGRm)

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## Requirements
1) Tight integration to Unity rendering (similar or same as uRaymarching did).
2) Rich parametrization (voxel size, volume dimension and etc)
3) Implementation of fancy effects: edge highligh, ao, fancy lighting.
4) Rendering in world space (obviously)
5) Multiple shader variants based on `#pragma multi_compile FANCY_LIGHTING_OFF FANCY_LIGHTING_ON`
6) **SUPPORT OF ORTHO PROJECTION AS WELL AS PERSPECTIVE**

## Roadmap
1) Draft implementation with hardcoded values
2) Integration with Standard shader
3) PBR params decoder from color data (*encoding convention is required!*)
4) Most important parametrization:
* Volume Size (bounds of providen volume)
* LOD (skip N pixel from providen texture)
5) Simple script to set `_Volume`, `_VolumeSize` and `transform.localScale` based on provided texture
6) Implementation of fancy effects
7) Rich parametrization

## Additional information:

To simplify process of developement I am highly recommended to few packages to your Unity project:
1) Install Unity 2018.1 or newer
2) Open `Packages/manifest.json` in your project
3) Add 2 extra dependencies:

    "com.texture3d.preview": "git://github.com/alerdenisov/com.texture3d.preview.git",
    "com.vox.importer": "git://github.com/alerdenisov/com.vox.importer.git"

5) Let unity resolve them
6) Open `Packages/vox Importer/vox` in Project tree
7) Use one of volumetric texture imported from MagicaVoxel builtin model.