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Although Htex by Jonathan Dupuy is elegant for Catmull-Clark Surface, but we also want to support Triangle Subdivision Scheme, which doesn't seems to be a good fit for Htex.
Mesh Colors by Cem Yuksel, or rather some variations of the Patch Texture, seems to works well with both quad/tri scheme. So we will tried Mesh Colors.
We don't want uv coordinate because of seam and duplicate vertex problems.
Mesh Color Patch Texture give us. (According to Cem Yuksel)
- No mapping! (implicit uv mapping)
- Local resolution readjustment
- Model editing after painting!
- No seams!
- Correct mip-maps
- Correct anisotropic filtering
uv mapping is one of the most wasteful time sinks in asset creation. No mapping alone is worth the implementation costs.
Implementation detail
tried to fit 2 triangle together to form a quad then map the quad to patch texture.
fit one triangle to one patch texture if no good pair of triangle is founded.
quadrangulation should be simple. Round the triangle pair with the best shape, which is as rectangle as possible, minimized slanting.
triangle index to each Mesh Colors Patch.
Implementation Steps:
quad-forming
color material color working. shader code needed too. @done(2024/03/12)
triangles in checkbox color pattern, so we can see triangles? @done (2024/03/12)
pair triangles to form quad. @done (2024/03/18)
quads in checkbox color pattern, so we can see quad pairing. @done (2024/03/16)
new method of computing quad pairing, use angle of quad as metric(as rect as possible)@done(2024/03/29)
texture-packing
compute the size of each quad/tri patch occupy. @done(2024/03/30)
binned quad/tri to sizes(power of 2), power of 2 make a lot of operation much easier and more correct.
render quad/tri to texture.
packs and bins to one big texture. aka texture atlas
render mip-mapped textures. packs each level to one texture.
show the packed textures.
will use multiple array of texture instead of packing to big texture.
finally, render model with the new Mesh Colors Patch Texture.