fix verlet integration, add wind

[cloth_sim] / Scripts / cloth.js

diff --git a/Scripts/cloth.js b/Scripts/cloth.js
index f1ac682fa3c9a4841f425ee9412b0b9d523ff159..266af16a3f1236417b7efd8c0c8805508d508bca 100644 (file)
--- a/Scripts/cloth.js
+++ b/Scripts/cloth.js
@@ -156,12 +156,12 @@ export class Cloth {
           getVertexIndex(x + 1, y + 1),\r
         );\r
 \r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x + 1, y)));\r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x, y + 1)));\r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x + 1, y + 1)));\r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x + 1, y), getVertexIndex(x, y + 1)));\r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x + 1, y), getVertexIndex(x + 1, y + 1)));\r
-        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y + 1), getVertexIndex(x + 1, y + 1)));\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x + 1, y)));         // oben\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x, y + 1)));         // links\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y), getVertexIndex(x + 1, y + 1)));     // oben links  -> unten rechts diagonal\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x + 1, y), getVertexIndex(x, y + 1)));     // oben rechts -> unten links diagonal\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x + 1, y), getVertexIndex(x + 1, y + 1))); // rechts\r
+        newFace.springs.push(new Spring(vertices, getVertexIndex(x, y + 1), getVertexIndex(x + 1, y + 1))); // unten\r
 \r
         faces.push(newFace);\r
       }\r
@@ -247,6 +247,7 @@ export class Cloth {
      * needed for View Frustum Culling internally\r
      */\r
     this.geometry.computeBoundingSphere();\r
+    this.geometry.computeFaceNormals();\r
   }\r
 \r
   /**\r
@@ -350,6 +351,7 @@ export class Cloth {
     this.geometry.verticesNeedUpdate = true;\r
     this.geometry.elementsNeedUpdate = true;\r
     this.geometry.computeBoundingSphere();\r
+    this.geometry.computeFaceNormals();\r
 \r
   }\r
 \r
@@ -371,7 +373,7 @@ getAcceleration(vertexIndex, dt) {
   // constant gravity\r
   let g = new THREE.Vector3(0, -9.8, 0);\r
   // stiffness\r
-  let k = 500;\r
+  let k = 1000;\r
 \r
   // Wind vector\r
   let fWind = new THREE.Vector3(\r
@@ -379,13 +381,12 @@ getAcceleration(vertexIndex, dt) {
     Math.cos(vertex.z * this.time),\r
     Math.sin(Math.cos(5 * vertex.x * vertex.y * vertex.z))\r
   );\r
-  fWind.set(0, 0, 0);\r
 \r
   /**\r
    * constant determined by the properties of the surrounding fluids (air)\r
    * achievement of cloth effects through try out\r
    * */\r
-  let a = 0.01;\r
+  let a = 0.1;\r
   \r
   let velocity = new THREE.Vector3(\r
     (this.previousPositions[vertexIndex].x - vertex.x) / dt,\r
@@ -401,23 +402,69 @@ getAcceleration(vertexIndex, dt) {
 \r
   // Get the bounding springs and add them to the needed springs\r
   // TODO: optimize\r
-  for (let i in this.faces) {\r
-    if (this.faces[i].a == vertexIndex || this.faces[i].b == vertexIndex || this.faces[i].c == vertexIndex || this.faces[i].d == vertexIndex) {\r
-      for (let j in this.faces[i].springs) {\r
-        if (this.faces[i].springs[j].index1 == vertexIndex || this.faces[i].springs[j].index2 == vertexIndex) {\r
 \r
-          let spring = this.faces[i].springs[j];\r
-          let springDirection = spring.getDirection(this.geometry.vertices);\r
+  const numPointsX = 10;\r
+  const numPointsY = 10;\r
+  const numFacesX = numPointsX - 1;\r
+  const numFacesY = numPointsY - 1;\r
 \r
+  function getFaceIndex(x, y) {\r
+    return y * numFacesX + x;\r
+  }\r
 \r
-          if (this.faces[i].springs[j].index1 == vertexIndex)\r
-            springDirection.multiplyScalar(-1);\r
-     \r
-          springSum.add(springDirection.multiplyScalar(k * (spring.restLength - spring.currentLength)));\r
+  let indexX = vertexIndex % numPointsX;\r
+  let indexY = Math.floor(vertexIndex / numPointsX);\r
+\r
+  let springs = [];\r
+\r
+  // 0  oben\r
+  // 1  links\r
+  // 2  oben links  -> unten rechts diagonal\r
+  // 3  oben rechts -> unten links diagonal\r
+  // 4  rechts\r
+  // 5  unten\r
+\r
+  let ul = indexX > 0 && indexY < numPointsY - 1;\r
+  let ur = indexX < numPointsX - 1 && indexY < numPointsY - 1;\r
+  let ol = indexX > 0 && indexY > 0;\r
+  let or = indexX < numPointsX - 1 && indexY > 0;\r
+\r
+  if (ul) {\r
+    let faceUL = this.faces[getFaceIndex(indexX - 1, indexY)];\r
+    springs.push(faceUL.springs[3]);\r
+    if (!ol)\r
+      springs.push(faceUL.springs[0]);\r
+    springs.push(faceUL.springs[4]);\r
+  }\r
+  if (ur) {\r
+    let faceUR = this.faces[getFaceIndex(indexX, indexY)];\r
+    springs.push(faceUR.springs[2]);\r
+    if (!or)\r
+      springs.push(faceUR.springs[0]);\r
+    if (!ul)\r
+      springs.push(faceUR.springs[1]);\r
+  }\r
+  if (ol) {\r
+    let faceOL = this.faces[getFaceIndex(indexX - 1, indexY - 1)];\r
+    springs.push(faceOL.springs[2]);\r
+    springs.push(faceOL.springs[4]);\r
+    springs.push(faceOL.springs[5]);\r
+  }\r
+  if (or) {\r
+    let faceOR = this.faces[getFaceIndex(indexX , indexY - 1)];\r
+    springs.push(faceOR.springs[3]);\r
+    if (!ol)\r
+      springs.push(faceOR.springs[1]);\r
+    springs.push(faceOR.springs[5]);\r
+  }\r
 \r
-        }\r
-      }\r
-    }\r
+  for (let spring of springs) {\r
+    let springDirection = spring.getDirection(this.geometry.vertices);\r
+\r
+    if (spring.index1 == vertexIndex)\r
+      springDirection.multiplyScalar(-1);\r
+\r
+    springSum.add(springDirection.multiplyScalar(k * (spring.restLength - spring.currentLength)));\r
   }\r
   \r
   let result = new THREE.Vector3(1, 1, 1);\r
@@ -442,13 +489,19 @@ verlet(currentPosition, previousPosition, acceleration, passedTime) {
   // next position = 2 * current Position - previous position + acceleration * (passed time)^2\r
   // acceleration (dv/dt) = F(net)\r
   // Dependency for one vertex: gravity, fluids/air, springs\r
-\r
+  const DRAG = 0.97;\r
   let nextPosition = new THREE.Vector3(\r
-    (2 * currentPosition.x) - previousPosition.x + acceleration.x * (passedTime * passedTime),\r
-    (2 * currentPosition.y) - previousPosition.y + acceleration.y * (passedTime * passedTime),\r
-    (2 * currentPosition.z) - previousPosition.z + acceleration.z * (passedTime * passedTime),\r
+    (currentPosition.x - previousPosition.x) * DRAG + currentPosition.x + acceleration.x * (passedTime * passedTime),\r
+    (currentPosition.y - previousPosition.y) * DRAG + currentPosition.y + acceleration.y * (passedTime * passedTime),\r
+    (currentPosition.z - previousPosition.z) * DRAG + currentPosition.z + acceleration.z * (passedTime * passedTime),\r
   );\r
 \r
+  // let nextPosition = new THREE.Vector3(\r
+  //   (2 * currentPosition.x) - previousPosition.x + acceleration.x * (passedTime * passedTime),\r
+  //   (2 * currentPosition.y) - previousPosition.y + acceleration.y * (passedTime * passedTime),\r
+  //   (2 * currentPosition.z) - previousPosition.z + acceleration.z * (passedTime * passedTime),\r
+  // );\r
+\r
   return nextPosition;\r
 }\r
 \r
@@ -462,5 +515,12 @@ euler(currentPosition, acceleration, passedTime) {
   return nextPosition;\r
 }\r
 \r
+wind(intersects) {\r
+  let intersect = intersects[0];\r
+  this.geometry.vertices[intersect.face.a].z -= 0.05;\r
+  this.geometry.vertices[intersect.face.b].z -= 0.05;\r
+  this.geometry.vertices[intersect.face.c].z -= 0.05;\r
+}\r
+\r
 }\r
 \r