Export the POM march as a composable parallaxOcclusionUv function#9
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Export the POM march as a composable parallaxOcclusionUv function#9promontis wants to merge 1 commit into
promontis wants to merge 1 commit into
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The march was locked inside createPomMaterial: single height texture, parallaxDirection tangent frame, fixed 24-40 layers, [0,1] discard. Using it on a layered terrain (blended height maps, world-XZ ground frame, distance-faded depth) meant copying the loop out by hand. parallaxOcclusionUv(sampleHeight, options?) exposes the same linear search + binary refinement with: - a height-sampler callback (uv, ddx, ddy) so the field can be a blend, a select between layers, or fully procedural, with start-UV gradients available for mip pinning - caller-supplied startUv / viewDirTs / depthScale nodes, so any tangent frame works and depth can be faded with distance - minLayers/maxLayers/refinementSteps/minViewZ tuning, with a fixed layer count when min == max - edgeBehavior: 'discard' (single-tile, unchanged default) or 'none' for repeating surfaces createPomMaterial now calls it internally; behaviour is unchanged. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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What
Extracts the parallax-occlusion march out of
createPomMaterialinto a new exported TSL primitive:createPomMaterialis refactored on top of it — its behaviour and public API are unchanged.Why
I'm using this POM technique in a WebGPU terrain renderer, where the material-level API can't be used directly because the terrain needs:
select/blend between forest and moss displacement maps, not one texture. Solved with asampleHeight(uv, ddx, ddy)callback; the start-UV gradients are passed in so the callback can mip-pin with.sample(uv).grad(ddx, ddy).viewDirTsis caller-supplied instead of hard-wired toparallaxDirection.depthScaleaccepts any node, so it can be driven to zero with distance and the march exits on its first step.minLayers/maxLayers(equal = fixed count, the adaptive mix is skipped),refinementSteps,minViewZ, andedgeBehavior: 'none'for repeating surfaces where the[0,1]discard is wrong.Notes
@promontis/threejs-pom/parallaxOcclusionUv+ entry in the Vite lib config.npm run build(lib + demo) passes. No behaviour change for existing users — the default options reproduce the old constants exactly, including the discard.WebGPU/TSL context: tested against the same march running in a
MeshStandardNodeMaterialcolorNode graph onWebGPURenderer(Chrome, macOS).🤖 Generated with Claude Code