From: Patrick Schönberger <patrick.schoenberger@posteo.de>
Date: Fri, 22 Jan 2021 13:10:23 +0000 (+0100)
Subject: correct units, tweak parameters
X-Git-Url: https://gitweb.ps.run/cloth_sim/commitdiff_plain/14881afe547086f68764e27bd65c794b21271c63

correct units, tweak parameters
---

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index 600ac8f..1497583 100644
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -6,9 +6,9 @@
  */
 function vectorLength(a, b) {
   let v1 = new THREE.Vector3();
-  v1.set(a.x, a.y, a.z);
+  v1.copy(a);
   let v2 = new THREE.Vector3();
-  v2.set(b.x, b.y, b.z);
+  v2.copy(b);
 
   return v1.sub(v2).length();
 }
@@ -65,11 +65,8 @@ export class Spring {
   }
 
   getDirection(vertices) {
-    let direction = new THREE.Vector3(
-      vertices[this.index1].x,
-      vertices[this.index1].y,
-      vertices[this.index1].z
-    );
+    let direction = new THREE.Vector3();
+    direction.copy(vertices[this.index1]);
 
     direction.sub(vertices[this.index2]);
     direction.divideScalar(vectorLength(vertices[this.index1], vertices[this.index2]));
@@ -197,8 +194,10 @@ export class Cloth {
      * Copy vertices and initialize vertex weights to 0
      */
     for (let i in vertices) {
-      this.geometry.vertices.push(vertices[i]);
-      this.previousPositions.push(vertices[i]);
+      this.geometry.vertices.push(vertices[i].clone());
+      this.previousPositions.push(vertices[i].clone());
+      // this.geometry.vertices.push(vertices[i]);
+      // this.previousPositions.push(vertices[i]);
       this.vertexWeights.push(0);
       this.vertexRigidness.push(false);
     }
@@ -315,24 +314,25 @@ export class Cloth {
   time = 0;
   /**
    * 
-   * @param {number} dt 
+   * @param {number} dt time in seconds since last frame
    */
   simulate(dt) {
     for (let i in this.geometry.vertices) {
-      let currentPosition;
       let acceleration = this.getAcceleration(i, dt);
 
-      // TODO: decide on clamping
-      acceleration.clampLength(0, 100);
+      //acceleration.clampLength(0, 10);
+
+      if (Math.abs(acceleration.length()) <= 10e-4) {
+        acceleration.set(0, 0, 0);
+      }
  
-      currentPosition = this.verlet(this.geometry.vertices[i], this.previousPositions[i], acceleration, dt/500);
-      //currentPosition = this.euler(this.geometry.vertices[i], acceleration, dt/10);
+      let currentPosition = this.verlet(this.geometry.vertices[i].clone(), this.previousPositions[i].clone(), acceleration, dt);
+      //let currentPosition = this.euler(this.geometry.vertices[i], acceleration, dt);
      
-      this.previousPositions[i] = currentPosition;
-      this.geometry.vertices[i] = currentPosition;
+      this.previousPositions[i].copy(this.geometry.vertices[i]);
+      this.geometry.vertices[i].copy(currentPosition);
     }
-
-    //this.getAcceleration(1, dt, true);
+    //console.log(this.getAcceleration(1, dt));
     
     this.time += dt;
 
@@ -371,32 +371,31 @@ getAcceleration(vertexIndex, dt) {
   // constant gravity
   let g = new THREE.Vector3(0, -9.8, 0);
   // stiffness
-  let k = 300;
+  let k = 1000;
 
   // Wind vector
-  // TODO: include wind vector
   let fWind = new THREE.Vector3(
     Math.sin(vertex.x * vertex.y * this.time),
-    Math.cos(vertex.z* this.time),
+    Math.cos(vertex.z * this.time),
     Math.sin(Math.cos(5 * vertex.x * vertex.y * vertex.z))
   );
-  fWind = new THREE.Vector3(0, 0, 0);
+  fWind.set(0, 0, 0);
 
   /**
    * constant determined by the properties of the surrounding fluids (air)
    * achievement of cloth effects through try out
    * */
-  let a = 1;
+  let a = 0.01;
 
   let velocity = new THREE.Vector3(
-    (vertex.x - this.previousPositions[vertexIndex].x) * dt,
-    (vertex.y - this.previousPositions[vertexIndex].y) * dt,
-    (vertex.z - this.previousPositions[vertexIndex].z) * dt
+    (this.previousPositions[vertexIndex].x - vertex.x) / dt,
+    (this.previousPositions[vertexIndex].y - vertex.y) / dt,
+    (this.previousPositions[vertexIndex].z - vertex.z) / dt
   );
 
-  // TODO: include air resistance
-  let fAirResistance = velocity.multiply(velocity).multiplyScalar(-a);
-  fAirResistance = new THREE.Vector3(0, 0, 0);
+  //console.log(velocity, vertex, this.previousPositions[vertexIndex]);
+
+  let fAirResistance = velocity.cross(velocity).multiplyScalar(-a);
 
   let springSum = new THREE.Vector3(0, 0, 0);
 
@@ -411,10 +410,10 @@ getAcceleration(vertexIndex, dt) {
           let springDirection = spring.getDirection(this.geometry.vertices);
 
 
-          if (this.faces[i].springs[j].index2 == vertexIndex)
+          if (this.faces[i].springs[j].index1 == vertexIndex)
             springDirection.multiplyScalar(-1);
 
-          springSum.add(springDirection.multiplyScalar(k * (spring.currentLength - spring.restLength)));
+          springSum.add(springDirection.multiplyScalar(k * (spring.restLength - spring.currentLength)));
         }
       }
     }
diff --git a/Scripts/main.js b/Scripts/main.js
index ececd6a..8c61f82 100644
--- a/Scripts/main.js
+++ b/Scripts/main.js
@@ -1,6 +1,14 @@
 import { Face, Spring, Cloth } from './cloth.js';
 
 
+/**
+ * rendering
+ * Einheiten konsistent
+ * Wind
+ * evtl. an Stoff ziehen
+ */
+
+
 class Point {
   constructor(x, y) {
     this.x = x;
@@ -87,10 +95,10 @@ function init() {
 
   /**
    * function called every frame
-   * @param {number} dt - time passed since last frame
+   * @param {number} dt - time passed since last frame in ms
    */
   function animate(dt) {
-    cloth.simulate(dt);
+    cloth.simulate(dt/1000);
 
     setTimeout(() => {
       animate(frameTime);