From: Patrick Schönberger <patrick.schoenberger@posteo.de>
Date: Sat, 6 Feb 2021 10:38:43 +0000 (+0100)
Subject: add Constraint class, add constraints to cloth
X-Git-Url: https://gitweb.ps.run/cloth_sim/commitdiff_plain/19d9f67e228e9925958489574339448bb608c9db

add Constraint class, add constraints to cloth
---

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index 05ff6f1..db07ac3 100644
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -1,9 +1,13 @@
-// cloth rendering
-// simulate
-// setup scene
-
 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);
@@ -50,6 +54,32 @@ class Cloth {
         );
       }
     }
+
+    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();
@@ -68,17 +98,6 @@ class Cloth {
     const numPointsWidth = this.numPointsWidth;
     const numPointsHeight = this.numPointsHeight;
 
-    /**
-     * 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
-     */
-    function getVertexIndex(x, y) {
-      return y * numPointsWidth + x;
-    }
-
     /**
      * generate faces based on 4 vertices
      * and 6 springs each
@@ -86,14 +105,14 @@ class Cloth {
     for (let y = 0; y < numPointsHeight - 1; y++) {
       for (let x = 0; x < numPointsWidth - 1; x++) {
         indices.push(
-          getVertexIndex(x, y),
-          getVertexIndex(x+1, y),
-          getVertexIndex(x+1, y+1)
+          this.getVertexIndex(x, y),
+          this.getVertexIndex(x+1, y),
+          this.getVertexIndex(x+1, y+1)
         );
         indices.push(
-          getVertexIndex(x, y),
-          getVertexIndex(x+1, y+1),
-          getVertexIndex(x, y+1)
+          this.getVertexIndex(x, y),
+          this.getVertexIndex(x+1, y+1),
+          this.getVertexIndex(x, y+1)
         );
       }
     }
@@ -109,4 +128,20 @@ class Cloth {
   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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