X-Git-Url: https://gitweb.ps.run/cloth_sim/blobdiff_plain/8a3364b0cd057fcfb7f89da112b9032fee76e403..19d9f67e228e9925958489574339448bb608c9db:/Scripts/cloth.js

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index a05eb98..db07ac3 100644
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -1,3 +1,147 @@
-// cloth rendering
-// simulate
-// setup scene
\ No newline at end of file
+const MASS = 0.1;
+
+class Constraint {
+  constructor(p1, p2, distance) {
+    this.p1 = p1;
+    this.p2 = p2;
+    this.distance = distance;
+  }
+}
+
+class Particle {
+  constructor(x, y, z, mass) {
+    this.position = new THREE.Vector3(x, y, z);
+    this.previous = new THREE.Vector3(x, y, z);
+    this.acceleration = new THREE.Vector3(0, 0, 0);
+    this.mass = mass;
+  }
+  addForce(force) {
+
+  }
+  verlet(dt) {
+
+  }
+}
+
+class Cloth {
+  constructor(width, height, numPointsWidth, numPointsHeight) {
+    this.width = width;
+    this.height = height;
+    this.numPointsWidth = numPointsWidth;
+    this.numPointsHeight = numPointsHeight;
+
+    /**
+     * distance between two vertices horizontally/vertically
+     * divide by the number of points minus one
+     * because there are (n - 1) lines between n vertices
+     */
+    let stepWidth = width / (numPointsWidth - 1);
+    let stepHeight = height / (numPointsHeight - 1);
+
+    /**
+     * iterate over the number of vertices in x/y axis
+     * and add a new Particle to "particles"
+     */
+    this.particles = [];
+    for (let y = 0; y < numPointsHeight; y++) {
+      for (let x = 0; x < numPointsWidth; x++) {
+        this.particles.push(
+          new Particle(
+            (x - ((numPointsWidth-1)/2)) * stepWidth,
+            height - (y + ((numPointsHeight-1)/2)) * stepHeight,
+            0,
+            MASS)
+        );
+      }
+    }
+
+    const REST_DIST_X = width / (numPointsWidth-1);
+    const REST_DIST_Y = height / (numPointsHeight-1);
+
+    /**
+     * generate constraints (springs)
+     */
+    this.constraints = [];
+    for (let y = 0; y < numPointsHeight; y++) {
+      for (let x = 0; x < numPointsWidth; x++) {
+        if (x < numPointsWidth-1) {
+          this.constraints.push(new Constraint(
+            this.particles[this.getVertexIndex(x, y)],
+            this.particles[this.getVertexIndex(x+1, y)],
+            REST_DIST_X
+          ));
+        }
+        if (x < numPointsWidth-1) {
+          this.constraints.push(new Constraint(
+            this.particles[this.getVertexIndex(x, y)],
+            this.particles[this.getVertexIndex(x, y+1)],
+            REST_DIST_Y
+          ));
+        }
+      }
+    }
+  }
+  generateGeometry() {
+    const geometry = new THREE.BufferGeometry();
+
+    const vertices = [];
+    const normals = [];
+    const indices = [];
+
+    for (let particle of this.particles) {
+      vertices.push(
+        particle.position.x,
+        particle.position.y,
+        particle.position.z);
+    }
+
+    const numPointsWidth = this.numPointsWidth;
+    const numPointsHeight = this.numPointsHeight;
+
+    /**
+     * generate faces based on 4 vertices
+     * and 6 springs each
+     */
+    for (let y = 0; y < numPointsHeight - 1; y++) {
+      for (let x = 0; x < numPointsWidth - 1; x++) {
+        indices.push(
+          this.getVertexIndex(x, y),
+          this.getVertexIndex(x+1, y),
+          this.getVertexIndex(x+1, y+1)
+        );
+        indices.push(
+          this.getVertexIndex(x, y),
+          this.getVertexIndex(x+1, y+1),
+          this.getVertexIndex(x, y+1)
+        );
+      }
+    }
+
+    geometry.setIndex(indices);
+    geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));
+    //geometry.setAttribute('normal', new THREE.Float32BufferAttribute(normals, 3));
+    geometry.computeBoundingSphere();
+    geometry.computeVertexNormals();
+
+    return geometry;
+  }
+  updateGeometry(geometry) {
+
+  }
+  satisfyConstraints() {
+
+  }
+  simulate() {
+
+  }
+  /**
+   * helper function to calculate index of vertex
+   * in "vertices" array based on its x and y positions
+   * in the mesh
+   * @param {number} x - x index of vertex
+   * @param {number} y - y index of vertex
+   */
+  getVertexIndex(x, y) {
+    return y * this.numPointsWidth + x;
+  }
+}
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