- Fast! CPU and GPU efficient
- Only one geometry clone, no additional geometry created
- Works on skinned meshes
- Clone the geometry into a new shadow mesh (SM)
- Snap normals on the SM to avoid holes during the projection
- Project the back of the SM using normals
- Use normals to resize the rest of the SM (avoids self-shadowing artifacts)
- Bridge edges near every vertex where normals disagree to remove projection artifacts
- Sharp edges (i.e. BoxBufferGeometry)
- Adaptive normal resizing for thin geometries (using attributes?)
- Only works for closed surfaces (manifolds) so far
Related approach with more geometry involved: https://github.com/gkjohnson/threejs-sandbox/tree/master/shadow-volumes
Stencil part adapted from: https://raw.githack.com/dyarosla/shadowVolumeThreeJS/master/index.html
Shadow Volumes reference: http://nuclear.mutantstargoat.com/articles/volume_shadows_tutorial_nuclear.pdf
Demo character from: https://www.mixamo.com/