simulate

3 files changed, 83 insertions, 11 deletions

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index db07ac3..0c4f02c 100644
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -1,14 +1,35 @@
+const DAMPING = 0.03;

+const DRAG = 1 - DAMPING;

 const MASS = 0.1;

+const GRAVITY = new THREE.Vector3(0, -9.81 * MASS, 0);

+const K = 1;

+

+let tmpCorrection;

 

 class Constraint {

-  constructor(p1, p2, distance) {

+  constructor(p1, p2, restDist) {

     this.p1 = p1;

     this.p2 = p2;

-    this.distance = distance;

+    this.restDist = restDist;

+  }

+

+  satisfy() {

+    const diff = this.p2.position.clone().sub(this.p1.position);

+    const currentDist = diff.length();

+    if (currentDist == 0) return;

+    if (currentDist <= this.restDist) return;

+    const correction = diff.multiplyScalar(1 - (this.restDist / currentDist));

+    correction.multiplyScalar(K);

+    tmpCorrection = correction;

+    const correctionHalf = correction.multiplyScalar(0.5);

+    this.p1.position.add(correctionHalf);

+    this.p2.position.sub(correctionHalf);

   }

 }

 

 class Particle {

+  movable = true;

+

   constructor(x, y, z, mass) {

     this.position = new THREE.Vector3(x, y, z);

     this.previous = new THREE.Vector3(x, y, z);

@@ -16,10 +37,23 @@ class Particle {
     this.mass = mass;

   }

   addForce(force) {

-

+    this.acceleration.add(

+      force.clone().multiplyScalar(1/this.mass)

+    );

   }

   verlet(dt) {

-

+    // verlet algorithm

+    // next position = 2 * current Position - previous position + acceleration * (passed time)^2

+    // acceleration (dv/dt) = F(net)

+    const nextPosition = this.position.clone().sub(this.previous);

+    nextPosition.multiplyScalar(DRAG);

+    nextPosition.add(this.position);

+    nextPosition.add(this.acceleration.multiplyScalar(dt*dt));

+

+    this.previous = this.position;

+    this.position = nextPosition;

+

+    this.acceleration.set(0, 0, 0);

   }

 }

 

@@ -29,6 +63,7 @@ class Cloth {
     this.height = height;

     this.numPointsWidth = numPointsWidth;

     this.numPointsHeight = numPointsHeight;

+    this.windFactor = new THREE.Vector3(0.5, 0.2, 0.2);

 

     /**

      * distance between two vertices horizontally/vertically

@@ -55,6 +90,10 @@ class Cloth {
       }

     }

 

+    this.particles[this.getVertexIndex(0, 0)].movable = false;

+    this.particles[this.getVertexIndex(0, numPointsHeight-1)].movable = false;

+    this.particles[this.getVertexIndex(numPointsWidth-1, 0)].movable = false;

+

     const REST_DIST_X = width / (numPointsWidth-1);

     const REST_DIST_Y = height / (numPointsHeight-1);

 

@@ -71,7 +110,7 @@ class Cloth {
             REST_DIST_X

           ));

         }

-        if (x < numPointsWidth-1) {

+        if (y < numPointsHeight-1) {

           this.constraints.push(new Constraint(

             this.particles[this.getVertexIndex(x, y)],

             this.particles[this.getVertexIndex(x, y+1)],

@@ -126,13 +165,44 @@ class Cloth {
     return geometry;

   }

   updateGeometry(geometry) {

-

-  }

-  satisfyConstraints() {

-

+    const positions = geometry.attributes.position.array;

+    for (let i in this.particles) {

+      let p = this.particles[i];

+      if (p.movable) {

+        positions[i*3+0] = p.position.x;

+        positions[i*3+1] = p.position.y;

+        positions[i*3+2] = p.position.z;

+      } else {

+        p.position = p.previous;

+      }

+    }

+    geometry.attributes.position.needsUpdate = true;

+    geometry.computeBoundingSphere();

+    geometry.computeVertexNormals();

   }

-  simulate() {

+  simulate(dt) {

+    let now = performance.now();

+    for (let particle of this.particles) {

+      let vertex = particle.position;

+      let fWind = new THREE.Vector3(

+        this.windFactor.x * (Math.sin(vertex.x * vertex.y * now)+1),

+        this.windFactor.y * Math.cos(vertex.z * now),

+        this.windFactor.z * Math.sin(Math.cos(5 * vertex.x * vertex.y * vertex.z))

+      );

+      // normalize then multiply?

+      particle.addForce(fWind);

+      // calculate wind with normal?

+

+      particle.addForce(GRAVITY);

+

+      particle.verlet(dt);

+    }

 

+    

+    for (let constraint of this.constraints) {

+      constraint.satisfy();

+    }

+    //console.log(tmpCorrection);

   }

   /**

    * helper function to calculate index of vertex

diff --git a/Scripts/main.js b/Scripts/main.js
index d54aa9f..3353f4d 100644
--- a/Scripts/main.js
+++ b/Scripts/main.js
@@ -98,7 +98,9 @@ function init() {
    * @param {number} dt - time passed since last frame in ms

    */

   function animate(dt) {

-    // simulate cloth

+    cloth.simulate(dt / 1000);

+

+    cloth.updateGeometry(clothGeometry);

     

     raycaster.setFromCamera( new THREE.Vector2((mousePos.x / w) * 2 - 1, ((h - mousePos.y) / h) * 2 - 1), camera );

 

diff --git a/Textures/DeutschlandFlagge.jpg b/Textures/DeutschlandFlagge.jpg
new file mode 100644
index 0000000..09e63ab
--- /dev/null
+++ b/Textures/DeutschlandFlagge.jpg