const K = 1;\r
const MAX_STRETCH = 1.5;\r
\r
-// Explosion am Anfang\r
-// Intersect mit Velocity?\r
-// Wind/Ziehen\r
-\r
const options = {\r
wind: true,\r
};\r
}\r
\r
satisfy() {\r
+ /** calculate current spring length */\r
const diff = this.p2.position.clone().sub(this.p1.position);\r
const currentDist = diff.length();\r
if (currentDist == 0) return;\r
if (currentDist <= this.restDist) return;\r
//const correction = diff.multiplyScalar(1 - (this.restDist / currentDist));\r
+\r
+ /** calculate necessary correction length and direction */\r
const correction = diff.multiplyScalar((currentDist - this.restDist) / currentDist);\r
correction.multiplyScalar(K);\r
- if (currentDist >= this.restDist * MAX_STRETCH) {\r
-\r
- }\r
- //correction.clampLength(0, 1);\r
const correctionHalf = correction.multiplyScalar(0.5);\r
\r
let p1movable = this.p1.movable && this.p1.movableTmp;\r
let p2movable = this.p2.movable && this.p2.movableTmp;\r
\r
+ /** apply correction if masses aren't fixed */\r
+ /** divide correction if both are movable */\r
if (p1movable && p2movable) {\r
this.p1.position.add(correctionHalf);\r
this.p2.position.sub(correctionHalf);\r
// verlet algorithm\r
// next position = 2 * current Position - previous position + acceleration * (passed time)^2\r
// acceleration (dv/dt) = F(net)\r
+ /** calculate velocity */\r
const nextPosition = this.position.clone().sub(this.previous);\r
+ /** apply drag */\r
nextPosition.multiplyScalar(DRAG);\r
+ /** add to current position and add acceleration */\r
nextPosition.add(this.position);\r
nextPosition.add(this.acceleration.multiplyScalar(dt*dt));\r
\r
this.position = nextPosition;\r
}\r
\r
+ /** reset for next frame */\r
this.acceleration.set(0, 0, 0);\r
}\r
}\r
}\r
}\r
\r
- //this.masses[this.getVertexIndex(0, 0)].movable = false;\r
+ /** attach cloth to flag pole */\r
const n = 3;\r
for (let i = 0; i < numPointsHeight; i++)\r
this.masses[this.getVertexIndex(0, i)].movable = false;\r
- //this.masses[this.getVertexIndex(0, numPointsHeight-1)].movable = false;\r
- //this.masses[this.getVertexIndex(numPointsWidth-1, 0)].movable = false;\r
\r
const REST_DIST_X = width / (numPointsWidth-1);\r
const REST_DIST_Y = height / (numPointsHeight-1);\r
\r
/**\r
- * generate springs (springs)\r
+ * generate springs (constraints)\r
*/\r
this.springs = [];\r
for (let y = 0; y < numPointsHeight; y++) {\r
const indices = [];\r
const uvs = [];\r
\r
+ /** create one vertex and one uv coordinate per mass */\r
for (let i in this.masses) {\r
let particle = this.masses[i];\r
vertices.push(\r
}\r
}\r
\r
+ /** set up geometry */\r
geometry.setIndex(indices);\r
geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));\r
geometry.setAttribute('uv', new THREE.Float32BufferAttribute(uvs, 2));\r
return geometry;\r
}\r
updateGeometry(geometry) {\r
+ /** update vertex positions in place */\r
const positions = geometry.attributes.position.array;\r
for (let i in this.masses) {\r
let p = this.masses[i];\r
positions[i*3+1] = p.position.y;\r
positions[i*3+2] = p.position.z;\r
}\r
+ /** update internally and recalculate bounding volume */\r
geometry.attributes.position.needsUpdate = true;\r
geometry.computeBoundingSphere();\r
geometry.computeVertexNormals();\r
simulate(dt) {\r
let now = performance.now();\r
for (let mass of this.masses) {\r
+ /** accumulate acceleration:\r
+ * - wind\r
+ * - gravity\r
+ */\r
let vertex = mass.position;\r
let fWind = new THREE.Vector3(\r
this.windFactor.x * (Math.sin(vertex.x * vertex.y * now)+1),\r
\r
mass.addForce(GRAVITY);\r
\r
+ /** integrate motion */\r
mass.verlet(dt);\r
}\r
\r
- \r
+ /** run satisfy step */\r
for (let constraint of this.springs) {\r
constraint.satisfy();\r
}\r
\r
+ /** prevent self-intersections */\r
this.intersect();\r
}\r
\r
p1.movableTmp = true;\r
p2.movableTmp = true;\r
\r
+ /** skip if i == j or if masses are adjacent */\r
if (i == j || (Math.abs(this.getX(i) - this.getX(j)) == 1 && Math.abs(this.getY(i) - this.getY(j)) == 1))\r
continue;\r
\r
+ /** calculate distance of points */\r
let dist = p1.position.distanceTo(p2.position);\r
+ /** calculate minimal resting distance (largest distance that should not be fallen below) */\r
let collisionDistance = Math.min(this.width / this.numPointsWidth, this.height / this.numPointsHeight);\r
// collisionDistance /= 2;\r
+ /** calculate "sphere intersection" */\r
if (dist < collisionDistance) {\r
// p1.movableTmp = false;\r
// p2.movableTmp = false;\r
+\r
+ /** vectors from p1 to p2 and the other way round */\r
let diffP2P1 = p1.position.clone().sub(p2.position).normalize();\r
diffP2P1.multiplyScalar((collisionDistance - dist) * 1.001 / 2);\r
let diffP1P2 = diffP2P1.clone().multiplyScalar(-1);\r
// let factor1 = (Math.PI - Math.acos(v1.dot(diffP2P1))) / Math.PI * 2;\r
// let factor2 = (Math.PI - Math.acos(v2.dot(diffP1P2))) / Math.PI * 2;\r
\r
+ /** move masses apart */\r
if (p1.movable)\r
p1.position.add(diffP2P1);\r
//p1.position.add(diffP2P1.multiplyScalar(factor1));\r
}\r
blow(camPos, intersects) {\r
let face = intersects[0].face;\r
+ /** vector from cam to intersection (wind) */\r
let dir = intersects[0].point.clone().sub(camPos).multiplyScalar(100);\r
+ /** apply to all vertices of affected face */\r
this.masses[face.a].addForce(dir);\r
this.masses[face.b].addForce(dir);\r
this.masses[face.c].addForce(dir);\r
}\r
drag(mousePosWorld, index) {\r
+ /** calculate vector from vertex to cursor */\r
let dir = mousePosWorld.clone().sub(this.masses[index].position).multiplyScalar(200);\r
+ /** apply to grabbed vertex */\r
this.masses[index].addForce(dir);\r
}\r
\r
projects / cloth_sim / blobdiff