mirror of
https://github.com/CNCKitchen/stlTexturizer.git
synced 2026-04-07 22:11:32 +00:00
CNCKitchen
334 lines
14 KiB
JavaScript
334 lines
14 KiB
JavaScript
import * as THREE from 'three';
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// Mapping mode constants (must match index.html <option value="…">)
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export const MODE_PLANAR_XY = 0;
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export const MODE_PLANAR_XZ = 1;
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export const MODE_PLANAR_YZ = 2;
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export const MODE_CYLINDRICAL = 3;
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export const MODE_SPHERICAL = 4;
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export const MODE_TRIPLANAR = 5;
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export const MODE_CUBIC = 6;
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// ── GLSL source ──────────────────────────────────────────────────────────────
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//
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// Preview strategy: NO vertex displacement.
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// All UV projection is done in the fragment shader so the underlying mesh
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// geometry is never modified. The displacement map is visualised via
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// per-fragment bump mapping (perturbing the shading normal from screen-space
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// height derivatives). `amplitude` scales the bump intensity only.
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const vertexShader = /* glsl */`
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precision highp float;
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varying vec3 vModelPos; // model-space position → UV computation in fragment
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varying vec3 vModelNormal; // model-space normal → stable UV blending (triplanar/cubic)
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varying vec3 vViewPos; // view-space position → TBN & specular
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varying vec3 vNormal; // view-space normal → lighting
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void main() {
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vModelPos = position;
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// Guard against degenerate zero-length normals (non-manifold / multi-body STLs
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// can produce averaged-to-zero normals at shared vertices between opposing bodies).
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// normalize(vec3(0)) is undefined in GLSL and produces NaN on most GPUs,
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// which then turns the entire fragment black.
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vec3 safeN = length(normal) > 1e-6 ? normalize(normal) : vec3(0.0, 0.0, 1.0);
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vModelNormal = safeN;
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vec4 mvPos = modelViewMatrix * vec4(position, 1.0);
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vViewPos = mvPos.xyz;
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vNormal = normalize(normalMatrix * safeN);
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gl_Position = projectionMatrix * mvPos;
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}
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`;
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const fragmentShader = /* glsl */`
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precision highp float;
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uniform sampler2D displacementMap;
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uniform int mappingMode;
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uniform vec2 scaleUV;
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uniform float amplitude;
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uniform vec2 offsetUV;
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uniform float rotation;
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uniform vec3 boundsMin;
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uniform vec3 boundsSize;
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uniform vec3 boundsCenter;
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uniform float bottomAngleLimit; // degrees from horizontal; 0 = disabled
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uniform float topAngleLimit; // degrees from horizontal; 0 = disabled
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uniform float mappingBlend; // 0 = sharp seams, 1 = fully blended
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uniform float seamBandWidth; // width of the blend zone near cube-face seams
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uniform int symmetricDisplacement; // 1 = remap [0,1]→[-1,1] so 50% grey = no disp
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varying vec3 vModelPos;
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varying vec3 vModelNormal;
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varying vec3 vViewPos;
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varying vec3 vNormal;
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const float PI = 3.14159265358979;
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const float TWO_PI = 6.28318530717959;
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const float CUBIC_AXIS_EPSILON = 1e-4;
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int dominantCubicAxis(vec3 n) {
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vec3 absN = abs(n);
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if (absN.x >= absN.y - CUBIC_AXIS_EPSILON && absN.x >= absN.z - CUBIC_AXIS_EPSILON) return 0;
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if (absN.y >= absN.z - CUBIC_AXIS_EPSILON) return 1;
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return 2;
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}
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vec3 cubicBlendWeights(vec3 n) {
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vec3 absN = abs(n);
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int axis = dominantCubicAxis(n);
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float primary = axis == 0 ? absN.x : axis == 1 ? absN.y : absN.z;
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float secondary = axis == 0 ? max(absN.y, absN.z)
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: axis == 1 ? max(absN.x, absN.z)
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: max(absN.x, absN.y);
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if (mappingBlend < 0.001 || primary - secondary <= CUBIC_AXIS_EPSILON) {
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if (axis == 0) return vec3(1.0, 0.0, 0.0);
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if (axis == 1) return vec3(0.0, 1.0, 0.0);
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return vec3(0.0, 0.0, 1.0);
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}
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vec3 oneHot = axis == 0 ? vec3(1.0, 0.0, 0.0)
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: axis == 1 ? vec3(0.0, 1.0, 0.0)
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: vec3(0.0, 0.0, 1.0);
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float seamWidth = max(seamBandWidth, CUBIC_AXIS_EPSILON * 2.0);
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float seamMixRaw = 1.0 - clamp((primary - secondary) / seamWidth, 0.0, 1.0);
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float seamMix = mappingBlend * seamMixRaw * seamMixRaw * (3.0 - 2.0 * seamMixRaw);
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if (seamMix <= 0.001) return oneHot;
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float power = 1.0 + (1.0 - seamMix) * 11.0;
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vec3 softWeights = pow(absN, vec3(power));
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softWeights /= dot(softWeights, vec3(1.0)) + 1e-6;
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vec3 blendedWeights = mix(oneHot, softWeights, seamMix);
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return blendedWeights / (dot(blendedWeights, vec3(1.0)) + 1e-6);
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}
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// Sample after applying scale + tiling
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float sampleMap(vec2 rawUV) {
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vec2 uv = rawUV / scaleUV + offsetUV;
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// rotate around tile centre
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float c = cos(rotation); float s = sin(rotation);
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uv -= 0.5;
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uv = vec2(c * uv.x - s * uv.y, s * uv.x + c * uv.y);
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uv += 0.5;
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return texture2D(displacementMap, uv).r;
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}
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// Height at this fragment for all projection modes.
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// Uses vModelPos / vModelNormal (model-space) so UV is stable as the camera orbits.
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float getHeight() {
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vec3 pos = vModelPos;
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vec3 MN = vModelNormal; // smooth interpolated normal → shading only
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vec3 rel = pos - boundsCenter;
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float maxDim = max(boundsSize.x, max(boundsSize.y, boundsSize.z));
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float md = max(maxDim, 1e-4);
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// Face-stable projection normal: cross product of screen-space position
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// derivatives is CONSTANT within a triangle (unlike the interpolated
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// vModelNormal), eliminating within-face texture z-fighting at seam
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// boundaries in cubic / triplanar mapping. Falls back to MN if degenerate.
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vec3 _dpx = dFdx(vModelPos);
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vec3 _dpy = dFdy(vModelPos);
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vec3 _fN = cross(_dpx, _dpy);
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vec3 PN = length(_fN) > 1e-10 ? normalize(_fN) : MN;
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if (mappingMode == 0) {
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return sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.y - boundsMin.y) / md));
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} else if (mappingMode == 1) {
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return sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.z - boundsMin.z) / md));
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} else if (mappingMode == 2) {
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return sampleMap(vec2((pos.y - boundsMin.y) / md, (pos.z - boundsMin.z) / md));
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} else if (mappingMode == 3) {
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// Cylindrical around Z axis (Z is up) with blendable side↔cap transition.
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float r = max(boundsSize.x, boundsSize.y) * 0.5;
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float C = TWO_PI * max(r, 1e-4);
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float hSide = sampleMap(vec2(atan(rel.y, rel.x) / TWO_PI + 0.5,
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(pos.z - boundsMin.z) / C));
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if (mappingBlend < 0.001) return hSide;
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float blendHalf = mappingBlend * 0.20;
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float capW = smoothstep(0.7 - blendHalf, 0.7 + blendHalf, abs(vModelNormal.z));
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float hCap = sampleMap(vec2(rel.x / C + 0.5, rel.y / C + 0.5));
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return mix(hSide, hCap, capW);
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} else if (mappingMode == 4) {
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// Spherical — Z is up
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float r = length(rel);
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float phi = acos(clamp(rel.z / max(r, 1e-4), -1.0, 1.0));
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float theta = atan(rel.y, rel.x);
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return sampleMap(vec2(theta / TWO_PI + 0.5, phi / PI));
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} else if (mappingMode == 5) {
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// Triplanar – smooth blend using face-stable projection normal (constant per triangle)
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vec3 blend = abs(PN);
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blend = pow(blend, vec3(4.0));
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blend /= dot(blend, vec3(1.0)) + 1e-4;
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float hXY = sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.y - boundsMin.y) / md));
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float hXZ = sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.z - boundsMin.z) / md));
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float hYZ = sampleMap(vec2((pos.y - boundsMin.y) / md, (pos.z - boundsMin.z) / md));
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return hXY * blend.z + hXZ * blend.y + hYZ * blend.x;
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} else {
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// Cubic (box) – use smooth normals for blend weights so high blend values
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// can hide seams, but fall back to the face-stable triangle normal when
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// the triangle sits on an ambiguous near-45° tie.
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float hYZ = sampleMap(vec2((pos.y - boundsMin.y) / md, (pos.z - boundsMin.z) / md));
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float hXZ = sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.z - boundsMin.z) / md));
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float hXY = sampleMap(vec2((pos.x - boundsMin.x) / md, (pos.y - boundsMin.y) / md));
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vec3 blendN = vModelNormal;
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vec3 absFaceN = abs(PN);
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float facePrimary = max(absFaceN.x, max(absFaceN.y, absFaceN.z));
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float faceSecondary = absFaceN.x + absFaceN.y + absFaceN.z - facePrimary - min(absFaceN.x, min(absFaceN.y, absFaceN.z));
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if (facePrimary - faceSecondary <= CUBIC_AXIS_EPSILON) blendN = PN;
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vec3 wts = cubicBlendWeights(blendN);
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return hYZ * wts.x + hXZ * wts.y + hXY * wts.z;
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}
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}
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void main() {
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// Flip normal for back faces so flipped-winding geometry still lights correctly.
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vec3 N = normalize(vNormal) * (gl_FrontFacing ? 1.0 : -1.0);
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float h = getHeight();
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if (symmetricDisplacement == 1) h = h * 2.0 - 1.0; // remap [0,1]→[-1,1]: 0.5 grey = zero
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// ── Surface angle masking (FDM: suppress texture on near-horizontal faces) ────
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// Use a 15° smoothstep fade above the threshold so the bump tapers gradually
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// into the masked region rather than cutting off abruptly at the boundary edge.
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float surfaceAngle = degrees(acos(clamp(abs(vModelNormal.z), 0.0, 1.0)));
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float maskBlend = 1.0;
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float FADE = 15.0;
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if (vModelNormal.z < 0.0 && bottomAngleLimit >= 1.0)
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maskBlend = min(maskBlend, smoothstep(bottomAngleLimit, bottomAngleLimit + FADE, surfaceAngle));
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if (vModelNormal.z >= 0.0 && topAngleLimit >= 1.0)
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maskBlend = min(maskBlend, smoothstep(topAngleLimit, topAngleLimit + FADE, surfaceAngle));
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h = mix(0.0, h, maskBlend); // blend toward neutral (zero-gradient → no bump)
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// ── Bump mapping via screen-space height derivatives ──────────────────
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float dhx = dFdx(h);
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float dhy = dFdy(h);
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vec3 dp1 = dFdx(vViewPos);
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vec3 dp2 = dFdy(vViewPos);
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vec3 T = dp1 - dot(dp1, N) * N;
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vec3 B = dp2 - dot(dp2, N) * N;
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float lenT = length(T);
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float lenB = length(B);
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T = lenT > 1e-5 ? T / lenT : vec3(1.0, 0.0, 0.0);
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B = lenB > 1e-5 ? B / lenB : vec3(0.0, 1.0, 0.0);
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// Bump strength normalised by screen-space position derivative so
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// the effect is independent of zoom level.
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float posScale = max(length(dp1) + length(dp2), 1e-6);
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float bumpStr = amplitude * 6.0 / posScale;
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vec3 bumpVec = N - bumpStr * (dhx * T + dhy * B);
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vec3 bumpN = length(bumpVec) > 1e-6 ? normalize(bumpVec) : N;
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// ── Shading ───────────────────────────────────────────────────────────
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vec3 baseColor = mix(vec3(0.50, 0.50, 0.50), vec3(0.22, 0.68, 0.68), maskBlend);
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vec3 L1 = normalize(vec3( 0.5, 0.8, 1.0));
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vec3 L2 = normalize(vec3(-0.5, -0.2, -0.6));
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vec3 V = normalize(-vViewPos);
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float diff1 = max(dot(bumpN, L1), 0.0);
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float diff2 = max(dot(bumpN, L2), 0.0) * 0.35;
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vec3 H1 = normalize(L1 + V);
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float spec = pow(max(dot(bumpN, H1), 0.0), 64.0) * 0.60;
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vec3 color = baseColor * 0.55 // ambient
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+ baseColor * diff1 * vec3(1.00, 0.96, 0.88) * 0.55 // key light
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+ baseColor * diff2 * vec3(0.80, 0.60, 0.50) * 0.15 // warm fill
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+ vec3(spec); // specular
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gl_FragColor = vec4(color, 1.0);
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}
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`;
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// ── Public API ────────────────────────────────────────────────────────────────
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/**
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* Create a ShaderMaterial for the displacement preview.
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* @param {THREE.Texture|null} displacementTexture
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* @param {object} settings – { mappingMode, scaleU, scaleV, amplitude, offsetU, offsetV, bounds }
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*/
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export function createPreviewMaterial(displacementTexture, settings) {
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const mat = new THREE.ShaderMaterial({
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vertexShader,
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fragmentShader,
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uniforms: buildUniforms(displacementTexture, settings),
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side: THREE.DoubleSide,
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});
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return mat;
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}
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/**
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* Update existing ShaderMaterial uniforms in-place (no recreate).
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*/
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export function updateMaterial(material, displacementTexture, settings) {
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const u = material.uniforms;
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if (displacementTexture && u.displacementMap.value !== displacementTexture) {
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u.displacementMap.value = displacementTexture;
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}
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u.mappingMode.value = settings.mappingMode;
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u.scaleUV.value.set(settings.scaleU, settings.scaleV);
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u.amplitude.value = settings.amplitude;
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u.offsetUV.value.set(settings.offsetU, settings.offsetV);
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u.rotation.value = (settings.rotation ?? 0) * Math.PI / 180;
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if (settings.bounds) {
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u.boundsMin.value.copy(settings.bounds.min);
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u.boundsSize.value.copy(settings.bounds.size);
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u.boundsCenter.value.copy(settings.bounds.center);
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}
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u.bottomAngleLimit.value = settings.bottomAngleLimit ?? 5.0;
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u.topAngleLimit.value = settings.topAngleLimit ?? 0.0;
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u.mappingBlend.value = settings.mappingBlend ?? 0.0;
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u.seamBandWidth.value = settings.seamBandWidth ?? 0.35;
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u.symmetricDisplacement.value = settings.symmetricDisplacement ? 1 : 0;
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}
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// ── Internal ──────────────────────────────────────────────────────────────────
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function buildUniforms(tex, settings) {
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const b = settings.bounds || {
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min: new THREE.Vector3(),
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size: new THREE.Vector3(1, 1, 1),
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center: new THREE.Vector3(),
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};
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return {
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displacementMap: { value: tex || createFallbackTexture() },
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mappingMode: { value: settings.mappingMode ?? MODE_TRIPLANAR },
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scaleUV: { value: new THREE.Vector2(settings.scaleU ?? 1, settings.scaleV ?? 1) },
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amplitude: { value: settings.amplitude ?? 1.0 },
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offsetUV: { value: new THREE.Vector2(settings.offsetU ?? 0, settings.offsetV ?? 0) },
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rotation: { value: ((settings.rotation ?? 0) * Math.PI / 180) },
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boundsMin: { value: b.min.clone() },
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boundsSize: { value: b.size.clone() },
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boundsCenter: { value: b.center.clone() },
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bottomAngleLimit: { value: settings.bottomAngleLimit ?? 5.0 },
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topAngleLimit: { value: settings.topAngleLimit ?? 0.0 },
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mappingBlend: { value: settings.mappingBlend ?? 0.0 },
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seamBandWidth: { value: settings.seamBandWidth ?? 0.35 },
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symmetricDisplacement: { value: settings.symmetricDisplacement ? 1 : 0 },
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};
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}
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function createFallbackTexture() {
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const canvas = document.createElement('canvas');
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canvas.width = canvas.height = 4;
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const ctx = canvas.getContext('2d');
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ctx.fillStyle = '#808080';
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ctx.fillRect(0, 0, 4, 4);
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const t = new THREE.CanvasTexture(canvas);
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t.wrapS = t.wrapT = THREE.RepeatWrapping;
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return t;
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}
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