Enhance displacement calculation and UV mapping; add gizmo visualization in viewer

js/displacement.js

@@ -26,8 +26,15 @@ export function applyDisplacement(geometry, imageData, imgWidth, imgHeight, sett
   const newPos = new Float32Array(count * 3);
   const newNrm = new Float32Array(count * 3);
 
-  const tmpPos = new THREE.Vector3();
-  const tmpNrm = new THREE.Vector3();
+  const tmpPos  = new THREE.Vector3();
+  const tmpNrm  = new THREE.Vector3();
+  // Reusable vectors for per-face normal computation
+  const vA      = new THREE.Vector3();
+  const vB      = new THREE.Vector3();
+  const vC      = new THREE.Vector3();
+  const edge1   = new THREE.Vector3();
+  const edge2   = new THREE.Vector3();
+  const faceNrm = new THREE.Vector3();
 
   const REPORT_EVERY = 5000;
 
@@ -35,7 +42,24 @@ export function applyDisplacement(geometry, imageData, imgWidth, imgHeight, sett
     tmpPos.fromBufferAttribute(posAttr, i);
     tmpNrm.fromBufferAttribute(nrmAttr, i);
 
-    const uvResult = computeUV(tmpPos, tmpNrm, settings.mappingMode, settings, bounds);
+    // Compute a stable face normal from the triangle's own vertex positions.
+    // The subdivider deduplicates vertices by position only, so shared corner
+    // vertices pick up whichever face's normal happened to be stored first.
+    // For hard-edged meshes (e.g. a cube) this corrupts the stored normals at
+    // edges/corners.  Recomputing from the triangle geometry is always correct
+    // for the flat-shaded STL source data and gives the right normal for both
+    // displacement direction and UV projection.
+    const base = Math.floor(i / 3) * 3;
+    vA.fromBufferAttribute(posAttr, base);
+    vB.fromBufferAttribute(posAttr, base + 1);
+    vC.fromBufferAttribute(posAttr, base + 2);
+    edge1.subVectors(vB, vA);
+    edge2.subVectors(vC, vA);
+    faceNrm.crossVectors(edge1, edge2);
+    // Fall back to the stored vertex normal for degenerate triangles
+    const useNrm = faceNrm.lengthSq() > 1e-10 ? faceNrm.normalize() : tmpNrm;
+
+    const uvResult = computeUV(tmpPos, useNrm, settings.mappingMode, settings, bounds);
 
     let grey;
     if (uvResult.triplanar) {
@@ -50,13 +74,13 @@ export function applyDisplacement(geometry, imageData, imgWidth, imgHeight, sett
 
     const disp = grey * settings.amplitude;
 
-    newPos[i*3]   = tmpPos.x + tmpNrm.x * disp;
-    newPos[i*3+1] = tmpPos.y + tmpNrm.y * disp;
-    newPos[i*3+2] = tmpPos.z + tmpNrm.z * disp;
+    newPos[i*3]   = tmpPos.x + useNrm.x * disp;
+    newPos[i*3+1] = tmpPos.y + useNrm.y * disp;
+    newPos[i*3+2] = tmpPos.z + useNrm.z * disp;
 
-    newNrm[i*3]   = tmpNrm.x;
-    newNrm[i*3+1] = tmpNrm.y;
-    newNrm[i*3+2] = tmpNrm.z;
+    newNrm[i*3]   = useNrm.x;
+    newNrm[i*3+1] = useNrm.y;
+    newNrm[i*3+2] = useNrm.z;
 
     if (onProgress && i % REPORT_EVERY === 0) onProgress(i / count);
   }

js/main.js

@@ -245,7 +245,7 @@ async function handleSTL(file) {
 
     // Default edge length = 1/100 of the largest bounding box dimension
     const maxDim = Math.max(bounds.size.x, bounds.size.y, bounds.size.z);
-    const defaultEdge = Math.max(0.1, Math.min(5.0, +(maxDim / 100).toFixed(2)));
+    const defaultEdge = Math.max(0.1, Math.min(5.0, +(maxDim / 200).toFixed(2)));
     settings.refineLength = defaultEdge;
     refineLenSlider.value = defaultEdge;
     refineLenVal.textContent = `${defaultEdge.toFixed(2)} mm`;

js/mapping.js

@@ -78,9 +78,9 @@ export function computeUV(pos, normal, mode, settings, bounds) {
       const az = Math.abs(normal.z);
       let uRaw, vRaw;
       if (ax >= ay && ax >= az) {
-        // ±X dominant → project onto YZ
-        uRaw = (pos.y - min.y) / Math.max(size.y, 1e-6);
-        vRaw = (pos.z - min.z) / Math.max(size.z, 1e-6);
+        // ±X dominant → project onto ZY (U=Z, V=Y keeps texture upright on side faces)
+        uRaw = (pos.z - min.z) / Math.max(size.z, 1e-6);
+        vRaw = (pos.y - min.y) / Math.max(size.y, 1e-6);
       } else if (ay >= ax && ay >= az) {
         // ±Y dominant → project onto XZ
         uRaw = (pos.x - min.x) / Math.max(size.x, 1e-6);

js/previewMaterial.js

@@ -106,8 +106,8 @@ const fragmentShader = /* glsl */`
       // Picks the single planar projection whose axis is most aligned with the face normal.
       vec3 absN = abs(MN);
       if (absN.x >= absN.y && absN.x >= absN.z) {
-        // ±X dominant → project onto YZ plane
-        return sampleMap((pos.yz - boundsMin.yz) / max(boundsSize.yz, vec2(1e-4)));
+        // ±X dominant → project onto ZY plane (U=Z, V=Y keeps texture upright on side faces)
+        return sampleMap((pos.zy - boundsMin.zy) / max(boundsSize.zy, vec2(1e-4)));
       } else if (absN.y >= absN.x && absN.y >= absN.z) {
         // ±Y dominant → project onto XZ plane
         return sampleMap((pos.xz - boundsMin.xz) / max(boundsSize.xz, vec2(1e-4)));

js/viewer.js

@@ -3,6 +3,57 @@ import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
 
 let renderer, camera, scene, controls, meshGroup, ambientLight, dirLight1, dirLight2, grid;
 let currentMesh = null;
+let gizmoScene, gizmoCamera;
+
+const GIZMO_PX     = 90;  // gizmo viewport size in CSS pixels
+const GIZMO_MARGIN = 14;
+
+function buildGizmo() {
+  gizmoScene  = new THREE.Scene();
+  gizmoCamera = new THREE.OrthographicCamera(-1.6, 1.6, 1.6, -1.6, 0.1, 10);
+  gizmoCamera.position.set(0, 0, 3);
+
+  const addAxis = (dir, hex, label) => {
+    // Shaft line
+    const shaft = new THREE.BufferGeometry().setFromPoints([
+      new THREE.Vector3(0, 0, 0),
+      dir.clone().multiplyScalar(0.78),
+    ]);
+    gizmoScene.add(new THREE.Line(
+      shaft,
+      new THREE.LineBasicMaterial({ color: hex, depthTest: false }),
+    ));
+
+    // Arrow-head cone
+    const cone = new THREE.Mesh(
+      new THREE.ConeGeometry(0.10, 0.24, 8),
+      new THREE.MeshBasicMaterial({ color: hex, depthTest: false }),
+    );
+    cone.position.copy(dir.clone().multiplyScalar(0.92));
+    cone.quaternion.setFromUnitVectors(new THREE.Vector3(0, 1, 0), dir);
+    gizmoScene.add(cone);
+
+    // Text label sprite
+    const c   = document.createElement('canvas');
+    c.width   = c.height = 64;
+    const ctx = c.getContext('2d');
+    ctx.fillStyle = `#${hex.toString(16).padStart(6, '0')}`;
+    ctx.font      = 'bold 46px Arial';
+    ctx.textAlign = 'center';
+    ctx.textBaseline = 'middle';
+    ctx.fillText(label, 32, 32);
+    const sprite = new THREE.Sprite(
+      new THREE.SpriteMaterial({ map: new THREE.CanvasTexture(c), depthTest: false }),
+    );
+    sprite.position.copy(dir.clone().multiplyScalar(1.26));
+    sprite.scale.set(0.42, 0.42, 1);
+    gizmoScene.add(sprite);
+  };
+
+  addAxis(new THREE.Vector3(1, 0, 0), 0xff4040, 'X');
+  addAxis(new THREE.Vector3(0, 1, 0), 0x44dd44, 'Y');
+  addAxis(new THREE.Vector3(0, 0, 1), 0x5599ff, 'Z');
+}
 
 export function initViewer(canvas) {
   // Renderer
@@ -54,6 +105,8 @@ export function initViewer(canvas) {
   controls.maxDistance = 3000;
   controls.screenSpacePanning = true;
 
+  buildGizmo();
+
   // Resize observer
   const resizeObserver = new ResizeObserver(() => onResize());
   resizeObserver.observe(canvas.parentElement);
@@ -63,7 +116,29 @@ export function initViewer(canvas) {
   (function animate() {
     requestAnimationFrame(animate);
     controls.update();
+
+    const cw = renderer.domElement.clientWidth;
+    const ch = renderer.domElement.clientHeight;
+
+    // 1. Main scene — full viewport
+    renderer.setScissorTest(false);
+    renderer.setViewport(0, 0, cw, ch);
     renderer.render(scene, camera);
+
+    // 2. Gizmo overlay — upper-right corner
+    //    WebGL y=0 is at bottom, so upper-right means large y.
+    const gx = cw - GIZMO_PX - GIZMO_MARGIN;
+    const gy = ch - GIZMO_PX - GIZMO_MARGIN;
+    gizmoCamera.quaternion.copy(camera.quaternion);
+    renderer.setScissorTest(true);
+    renderer.setScissor(gx, gy, GIZMO_PX, GIZMO_PX);
+    renderer.setViewport(gx, gy, GIZMO_PX, GIZMO_PX);
+    renderer.autoClear = false;
+    renderer.clearDepth();
+    renderer.render(gizmoScene, gizmoCamera);
+    renderer.autoClear = true;
+    renderer.setScissorTest(false);
+    renderer.setViewport(0, 0, cw, ch);
   })();
 }