GSOC 26: bumpTexture() for height maps - #9089
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I'm reading some more, I actually wonder if this should be what the obj format's map_bump refers to? This stackoverflow suggests normal maps were never officially added, and this issue for a common loader library talks about the lack of consensus for a normal map parameter. Did you have other references for the obj format using normal maps? If not maybe we should update our model importer to go through this bump map path instead, and keep the normal maps as just a a user-facing method for now and for the future gltf importer? |
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Let's add orbitControl() here, and some subtle rotation like in the other PR, + maybe some shininess to make it clearer?
I also notice a seam here too:
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done, added orbitControl(), the same subtle rotation, and turned on specular + shininess so the raised areas catch a highlight. reads much clearer.
the seam was the texture not tiling, same root cause as the one on the other pr. two parts to it here: the pattern now repeats a whole number of times across the image, and the example turns on textureWrap(REPEAT). the wrap matters specifically for bump maps because the shader reads a neighbouring texel to get the slope, so at u=1 that neighbour was running off the edge and clamping, which flattened the slope right at the seam. with both, it's gone.
…ghlights to the bump one
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closes #9088. follow up to #9067.
p5 has
normalTexture()for tangent space normal maps, where rgb encodes the surface normal. this addsbumpTexture()for the other kind: a grayscale height map, where brightness is height and the normal is worked out from how fast that height changes.how it works
both share one texture slot and differ by a mode flag the shader reads, so only one is active at a time and setting either replaces the other. that keeps it purely additive, nothing about
normalTexture()or the existing api changes.in bump mode the shader samples the map at the current texel and its two neighbours, and builds the tangent space normal from the difference. it reuses the same per vertex tangent frame normal mapping already uses, so no extra vertex data and it works in webgl1 too (no
dFdx). the texel size comes in as a uniform so the neighbour offsets are right for any map size.done in both webgl and webgpu, matching what we did for normal maps.
docs
the two techniques get confused a lot, and the obj format doesn't help by calling the slot
map_Bumpeven when the image is a normal map. so both reference entries now explain what image each one expects (grayscale height vs blue tinted directions) and cross link to each other.bumpTexture()has a runnable example, which i rendered to check it matches itsdescribe().loading a model is unchanged:
map_Bumpstill loads as a normal map, since that's what it has been.tests
added coverage for bump mode being set,
nullclearing it, and the two kinds replacing each other in the shared slot. full webgl + webgpu suites pass, including the existing normal map visual tests, which confirms mode 0 renders exactly as before.note: this is stacked on #9068, so that one goes in first.