add Constraint class, add constraints to cloth

[cloth_sim] / Scripts / cloth.js

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index f1068d4b6fc056e421b60f4e604c17c1b9c3d8b9..db07ac302cf916846f12ce487ef5e7b4636547a9 100644 (file)
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -1,4 +1,147 @@
-// cloth rendering\r
-// simulate\r
-// setup scene\r
-// orbit controls/skybox/flagge
\ No newline at end of file
+const MASS = 0.1;\r
+\r
+class Constraint {\r
+  constructor(p1, p2, distance) {\r
+    this.p1 = p1;\r
+    this.p2 = p2;\r
+    this.distance = distance;\r
+  }\r
+}\r
+\r
+class Particle {\r
+  constructor(x, y, z, mass) {\r
+    this.position = new THREE.Vector3(x, y, z);\r
+    this.previous = new THREE.Vector3(x, y, z);\r
+    this.acceleration = new THREE.Vector3(0, 0, 0);\r
+    this.mass = mass;\r
+  }\r
+  addForce(force) {\r
+\r
+  }\r
+  verlet(dt) {\r
+\r
+  }\r
+}\r
+\r
+class Cloth {\r
+  constructor(width, height, numPointsWidth, numPointsHeight) {\r
+    this.width = width;\r
+    this.height = height;\r
+    this.numPointsWidth = numPointsWidth;\r
+    this.numPointsHeight = numPointsHeight;\r
+\r
+    /**\r
+     * distance between two vertices horizontally/vertically\r
+     * divide by the number of points minus one\r
+     * because there are (n - 1) lines between n vertices\r
+     */\r
+    let stepWidth = width / (numPointsWidth - 1);\r
+    let stepHeight = height / (numPointsHeight - 1);\r
+\r
+    /**\r
+     * iterate over the number of vertices in x/y axis\r
+     * and add a new Particle to "particles"\r
+     */\r
+    this.particles = [];\r
+    for (let y = 0; y < numPointsHeight; y++) {\r
+      for (let x = 0; x < numPointsWidth; x++) {\r
+        this.particles.push(\r
+          new Particle(\r
+            (x - ((numPointsWidth-1)/2)) * stepWidth,\r
+            height - (y + ((numPointsHeight-1)/2)) * stepHeight,\r
+            0,\r
+            MASS)\r
+        );\r
+      }\r
+    }\r
+\r
+    const REST_DIST_X = width / (numPointsWidth-1);\r
+    const REST_DIST_Y = height / (numPointsHeight-1);\r
+\r
+    /**\r
+     * generate constraints (springs)\r
+     */\r
+    this.constraints = [];\r
+    for (let y = 0; y < numPointsHeight; y++) {\r
+      for (let x = 0; x < numPointsWidth; x++) {\r
+        if (x < numPointsWidth-1) {\r
+          this.constraints.push(new Constraint(\r
+            this.particles[this.getVertexIndex(x, y)],\r
+            this.particles[this.getVertexIndex(x+1, y)],\r
+            REST_DIST_X\r
+          ));\r
+        }\r
+        if (x < numPointsWidth-1) {\r
+          this.constraints.push(new Constraint(\r
+            this.particles[this.getVertexIndex(x, y)],\r
+            this.particles[this.getVertexIndex(x, y+1)],\r
+            REST_DIST_Y\r
+          ));\r
+        }\r
+      }\r
+    }\r
+  }\r
+  generateGeometry() {\r
+    const geometry = new THREE.BufferGeometry();\r
+\r
+    const vertices = [];\r
+    const normals = [];\r
+    const indices = [];\r
+\r
+    for (let particle of this.particles) {\r
+      vertices.push(\r
+        particle.position.x,\r
+        particle.position.y,\r
+        particle.position.z);\r
+    }\r
+\r
+    const numPointsWidth = this.numPointsWidth;\r
+    const numPointsHeight = this.numPointsHeight;\r
+\r
+    /**\r
+     * generate faces based on 4 vertices\r
+     * and 6 springs each\r
+     */\r
+    for (let y = 0; y < numPointsHeight - 1; y++) {\r
+      for (let x = 0; x < numPointsWidth - 1; x++) {\r
+        indices.push(\r
+          this.getVertexIndex(x, y),\r
+          this.getVertexIndex(x+1, y),\r
+          this.getVertexIndex(x+1, y+1)\r
+        );\r
+        indices.push(\r
+          this.getVertexIndex(x, y),\r
+          this.getVertexIndex(x+1, y+1),\r
+          this.getVertexIndex(x, y+1)\r
+        );\r
+      }\r
+    }\r
+\r
+    geometry.setIndex(indices);\r
+    geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));\r
+    //geometry.setAttribute('normal', new THREE.Float32BufferAttribute(normals, 3));\r
+    geometry.computeBoundingSphere();\r
+    geometry.computeVertexNormals();\r
+\r
+    return geometry;\r
+  }\r
+  updateGeometry(geometry) {\r
+\r
+  }\r
+  satisfyConstraints() {\r
+\r
+  }\r
+  simulate() {\r
+\r
+  }\r
+  /**\r
+   * helper function to calculate index of vertex\r
+   * in "vertices" array based on its x and y positions\r
+   * in the mesh\r
+   * @param {number} x - x index of vertex\r
+   * @param {number} y - y index of vertex\r
+   */\r
+  getVertexIndex(x, y) {\r
+    return y * this.numPointsWidth + x;\r
+  }\r
+}
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