simplified box geometry

src/mol-geo/primitive/box.ts

@@ -11,97 +11,64 @@ import { Vec3 } from 'mol-math/linear-algebra'
 export const DefaultBoxProps = {
     width: 1,
     height: 1,
-    depth: 1,
-    widthSegments: 1,
-    heightSegments: 1,
-    depthSegments: 1
+    depth: 1
 }
 export type BoxProps = Partial<typeof DefaultBoxProps>
 
+const tmpVector = Vec3.zero();
+
 export default function Box(props?: BoxProps) {
-    const { width, height, depth, widthSegments, heightSegments, depthSegments } = { ...DefaultBoxProps, ...props }
+    const { width, height, depth } = { ...DefaultBoxProps, ...props }
 
     // buffers
-    const indices: number[] = [];
-    const vertices: number[] = [];
-    const normals: number[] = [];
+    const vertices = new Float32Array(72);
+    const normals = new Float32Array(72);
+    const indices = new Uint32Array(36);
 
     // helper variables
-    let numberOfVertices = 0;
+    let vertexCount = 0;
 
     // build each side of the box geometry
-    buildPlane(2, 1, 0, -1, -1, depth, height, width, depthSegments, heightSegments); // px
-    buildPlane(2, 1, 0, 1, -1, depth, height, -width, depthSegments, heightSegments); // nx
-    buildPlane(0, 2, 1, 1, 1, width, depth, height, widthSegments, depthSegments); // py
-    buildPlane(0, 2, 1, 1, -1, width, depth, -height, widthSegments, depthSegments); // ny
-    buildPlane(0, 1, 2, 1, -1, width, height, depth, widthSegments, heightSegments); // pz
-    buildPlane(0, 1, 2, -1, -1, width, height, -depth, widthSegments, heightSegments); // nz
-
-    return {
-        vertices: new Float32Array(vertices),
-        normals: new Float32Array(normals),
-        indices: new Uint32Array(indices)
-    }
-
-    function buildPlane(u: number, v: number, w: number, udir: number, vdir: number, width: number, height: number, depth: number, gridX: number, gridY: number) {
-
-        const segmentWidth = width / gridX;
-        const segmentHeight = height / gridY;
+    buildPlane(2, 1, 0, -1, -1, depth, height, width); // px
+    buildPlane(2, 1, 0, 1, -1, depth, height, -width); // nx
+    buildPlane(0, 2, 1, 1, 1, width, depth, height); // py
+    buildPlane(0, 2, 1, 1, -1, width, depth, -height); // ny
+    buildPlane(0, 1, 2, 1, -1, width, height, depth); // pz
+    buildPlane(0, 1, 2, -1, -1, width, height, -depth); // nz
 
-        const widthHalf = width / 2;
-        const heightHalf = height / 2;
-        const depthHalf = depth / 2;
-
-        const gridX1 = gridX + 1;
-        const gridY1 = gridY + 1;
-
-        let vertexCounter = 0;
-
-        const vector = Vec3.zero();
+    return { vertices, normals, indices }
 
+    function buildPlane(u: number, v: number, w: number, udir: number, vdir: number, width: number, height: number, depth: number) {
         // generate vertices and normals
-        for (let iy = 0; iy < gridY1; ++iy) {
-            const y = iy * segmentHeight - heightHalf;
-            for (let ix = 0; ix < gridX1; ++ix) {
-                const x = ix * segmentWidth - widthHalf;
-
-                // set values to correct vector component
-                vector[ u ] = x * udir;
-                vector[ v ] = y * vdir;
-                vector[ w ] = depthHalf;
-
-                // now apply vector to vertex buffer
-                vertices.push(...vector);
-
-                // set values to correct vector component
-                vector[ u ] = 0;
-                vector[ v ] = 0;
-                vector[ w ] = depth > 0 ? 1 : -1;
-
-                // now apply vector to normal buffer
-                normals.push(...vector);
-
-                vertexCounter += 1;
-            }
-        }
-
-        // indices
-        // 1. you need three indices to draw a single face
-        // 2. a single segment consists of two faces
-        // 3. so we need to generate six (2*3) indices per segment
-        for (let iy = 0; iy < gridY; ++iy) {
-            for (let ix = 0; ix < gridX; ++ix) {
-                const a = numberOfVertices + ix + gridX1 * iy;
-                const b = numberOfVertices + ix + gridX1 * (iy + 1);
-                const c = numberOfVertices + (ix + 1) + gridX1 * (iy + 1);
-                const d = numberOfVertices + (ix + 1) + gridX1 * iy;
-
-                // faces
-                indices.push(a, b, d);
-                indices.push(b, c, d);
+        for (let iy = 0; iy < 2; ++iy) {
+            const y = iy * height - height / 2;
+            for (let ix = 0; ix < 2; ++ix) {
+                const x = ix * width - width / 2;
+
+                // set values to correct vector component and add to vertex buffer
+                tmpVector[u] = x * udir;
+                tmpVector[v] = y * vdir;
+                tmpVector[w] = depth / 2;
+                Vec3.toArray(tmpVector, vertices, vertexCount * 3);
+
+                // set values to correct vector component and add to normal buffer
+                tmpVector[u] = 0;
+                tmpVector[v] = 0;
+                tmpVector[w] = depth > 0 ? 1 : -1;
+                Vec3.toArray(tmpVector, normals, vertexCount * 3);
+
+                ++vertexCount;
             }
         }
 
-        numberOfVertices += vertexCounter;
+        // faces
+        const vc = vertexCount - 4
+        const iidx = (vc / 2) * 3
+        indices[iidx] = vc
+        indices[iidx + 1] = vc + 2
+        indices[iidx + 2] = vc + 1
+        indices[iidx + 3] = vc + 2
+        indices[iidx + 4] = vc + 3
+        indices[iidx + 5] = vc + 1
     }
 }
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