*/\r
function vectorLength(a, b) {\r
let v1 = new THREE.Vector3();\r
- v1.set(a.x, a.y, a.z);\r
+ v1.copy(a);\r
let v2 = new THREE.Vector3();\r
- v2.set(b.x, b.y, b.z);\r
+ v2.copy(b);\r
\r
return v1.sub(v2).length();\r
}\r
index1;\r
index2;\r
\r
- \r
+\r
/**\r
* set vertex indices\r
* and calculate inital length based on the\r
* vertex positions\r
- * @param {Array of Vector3} vertices \r
+ * @param {Array<Vector3>} vertices \r
* @param {number} index1 \r
* @param {number} index2 \r
*/\r
this.restLength = length;\r
this.currentLength = length;\r
}\r
+\r
+ getDirection(vertices) {\r
+ let direction = new THREE.Vector3();\r
+ direction.copy(vertices[this.index1]);\r
+\r
+ direction.sub(vertices[this.index2]);\r
+ direction.divideScalar(vectorLength(vertices[this.index1], vertices[this.index2]));\r
+\r
+ return direction;\r
+ }\r
+\r
+ update(vertices) {\r
+ let length = vectorLength(vertices[this.index1], vertices[this.index2]);\r
+ this.currentLength = length;\r
+ }\r
}\r
\r
/**\r
\r
vertexWeights = [];\r
\r
- \r
+ vertexRigidness = [];\r
+\r
+ fixedPoints = [];\r
+\r
+ externalForces = [];\r
+ windForce = 50;\r
+\r
+ windFactor = new THREE.Vector3(0, 0, 0);\r
+\r
/**\r
* creates a rectangular piece of cloth\r
* takes the size of the cloth\r
let vertices = [];\r
let faces = [];\r
\r
+ this.width = width;\r
+ this.height = height;\r
+ this.numPointsWidth = numPointsWidth;\r
+ this.numPointsHeight = numPointsHeight;\r
+\r
/**\r
* distance between two vertices horizontally/vertically\r
* divide by the number of points minus one\r
for (let y = 0; y < numPointsHeight; y++) {\r
for (let x = 0; x < numPointsWidth; x++) {\r
vertices.push(\r
- new THREE.Vector3(x * stepWidth, height - y * stepHeight, 0)\r
+ new THREE.Vector3((x - ((numPointsWidth-1)/2)) * stepWidth, height - (y + ((numPointsHeight-1)/2)) * stepHeight, 0)\r
);\r
}\r
}\r
function getVertexIndex(x, y) {\r
return y * numPointsWidth + x;\r
}\r
- \r
+\r
/**\r
* generate faces based on 4 vertices\r
* and 6 springs each\r
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
- \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
}\r
* with generated vertices and faces\r
*/\r
this.createExplicit(vertices, faces);\r
+\r
+ /**\r
+ * hand cloth from left and right upper corners\r
+ */\r
+ this.fixedPoints.push(getVertexIndex(0, 0));\r
+ this.fixedPoints.push(getVertexIndex(0, 19));\r
}\r
\r
/**\r
* (list of vertices and list of indices representing triangles)\r
* and calculate the weight of each face and split it between\r
* surrounding vertices\r
- * @param {Array of Vector3} vertices \r
- * @param {Array of Face} faces \r
+ * @param {Array<Vector3>} vertices \r
+ * @param {Array<Face>} faces \r
*/\r
createExplicit(vertices, faces) {\r
+\r
/**\r
* Copy vertices and initialize vertex weights to 0\r
*/\r
for (let i in vertices) {\r
- this.geometry.vertices.push(vertices[i]);\r
+ this.geometry.vertices.push(vertices[i].clone());\r
+ this.previousPositions.push(vertices[i].clone());\r
+ // this.geometry.vertices.push(vertices[i]);\r
+ // this.previousPositions.push(vertices[i]);\r
this.vertexWeights.push(0);\r
+ this.vertexRigidness.push(false);\r
+ this.externalForces.push(new THREE.Vector3(0,0,0));\r
}\r
/**\r
* copy faces,\r
this.geometry.faces.push(new THREE.Face3(\r
face.c, face.b, face.d\r
));\r
- \r
+\r
/**\r
* calculate area of face as combined area of\r
* its two composing triangles\r
yLength = vectorLength(this.geometry.vertices[face.c], this.geometry.vertices[face.d]);\r
weight += xLength * yLength / 2;\r
\r
+ weight *= 10;\r
+\r
/**\r
* split weight equally between four surrounding vertices\r
*/\r
* needed for View Frustum Culling internally\r
*/\r
this.geometry.computeBoundingSphere();\r
+ this.geometry.computeFaceNormals();\r
+ this.geometry.computeVertexNormals();\r
}\r
\r
/**\r
let geometry = new THREE.Geometry();\r
geometry.vertices.push(from);\r
geometry.vertices.push(to);\r
- let material = new THREE.LineBasicMaterial( { color: color, linewidth: 10 } );\r
+ let material = new THREE.LineBasicMaterial({ color: color, linewidth: 10 });\r
let line = new THREE.Line(geometry, material);\r
line.renderOrder = 1;\r
scene.add(line);\r
* @param {number} color \r
*/\r
function addPoint(point, color) {\r
- const geometry = new THREE.SphereGeometry( 0.05, 32, 32 );\r
- const material = new THREE.MeshBasicMaterial( { color: color } );\r
- const sphere = new THREE.Mesh( geometry, material );\r
+ const geometry = new THREE.SphereGeometry(0.05, 32, 32);\r
+ const material = new THREE.MeshBasicMaterial({ color: color });\r
+ const sphere = new THREE.Mesh(geometry, material);\r
sphere.position.set(point.x, point.y, point.z);\r
- scene.add( sphere );\r
+ scene.add(sphere);\r
}\r
\r
let lineColor = 0x000000;\r
addPoint(this.geometry.vertices[face.d], pointColor);\r
}\r
}\r
-}
\ No newline at end of file
+\r
+ previousPositions = [];\r
+ time = 0;\r
+ /**\r
+ * \r
+ * @param {number} dt time in seconds since last frame\r
+ */\r
+ simulate(dt) {\r
+ for (let i in this.geometry.vertices) {\r
+ let acceleration = this.getAcceleration(i, dt);\r
+\r
+ //acceleration.clampLength(0, 10);\r
+\r
+ if (Math.abs(acceleration.length()) <= 10e-4) {\r
+ acceleration.set(0, 0, 0);\r
+ }\r
+ \r
+ let currentPosition = this.verlet(this.geometry.vertices[i].clone(), this.previousPositions[i].clone(), acceleration, dt);\r
+ //let currentPosition = this.euler(this.geometry.vertices[i], acceleration, dt);\r
+ \r
+ this.previousPositions[i].copy(this.geometry.vertices[i]);\r
+ this.geometry.vertices[i].copy(currentPosition);\r
+ }\r
+ \r
+ this.checkIntersect();\r
+ \r
+ this.time += dt;\r
+\r
+ for (let face of this.faces) {\r
+ for (let spring of face.springs) {\r
+ spring.update(this.geometry.vertices);\r
+ }\r
+ }\r
+\r
+ /**\r
+ * let THREE JS compute bounding sphere around generated mesh\r
+ * needed for View Frustum Culling internally\r
+ */\r
+\r
+ this.geometry.verticesNeedUpdate = true;\r
+ this.geometry.elementsNeedUpdate = true;\r
+ this.geometry.computeBoundingSphere();\r
+ this.geometry.computeFaceNormals();\r
+ this.geometry.computeVertexNormals();\r
+\r
+ }\r
+\r
+checkIntersect() {\r
+ let npw = this.numPointsWidth;\r
+ function getX(i, ) { return i % npw; }\r
+ function getY(i) { return Math.floor(i / npw); }\r
+ for (let i in this.geometry.vertices) {\r
+ for (let j in this.geometry.vertices) {\r
+ this.vertexRigidness[i] = false;\r
+ this.vertexRigidness[j] = false;\r
+ if (i == j || (Math.abs(getX(i) - getX(j)) == 1 && Math.abs(getY(i) - getY(j)) == 1))\r
+ continue;\r
+ let posI = this.geometry.vertices[i];\r
+ let posJ = this.geometry.vertices[j];\r
+ let dist = posI.distanceTo(posJ);\r
+ const collisionDistance = Math.min(this.width / this.numPointsWidth, this.height / this.numPointsHeight);\r
+ if (dist < collisionDistance) {\r
+ this.vertexRigidness[i] = true;\r
+ this.vertexRigidness[j] = true;\r
+ let diff = this.geometry.vertices[i].clone().sub(this.geometry.vertices[j]).normalize().multiplyScalar((collisionDistance - dist) * 1.001 / 2);\r
+ if (!(this.fixedPoints.includes(i) || this.fixedPoints.includes(j))) {\r
+ this.geometry.vertices[i].add(diff);\r
+ this.geometry.vertices[j].sub(diff);\r
+ }\r
+ }\r
+ }\r
+ }\r
+}\r
+\r
+/**\r
+ * Equation of motion for each vertex which represents the acceleration \r
+ * @param {number} vertexIndex The index of the current vertex whose acceleration should be calculated\r
+ * @param {number} dt The time passed since last frame\r
+ */\r
+getAcceleration(vertexIndex, dt) {\r
+ if (this.fixedPoints.includes(parseInt(vertexIndex)) ||\r
+ this.vertexRigidness[vertexIndex]) {\r
+ return new THREE.Vector3(0, 0, 0);\r
+ }\r
+\r
+ let externalForce = this.externalForces[vertexIndex];\r
+ let vertex = this.geometry.vertices[vertexIndex];//.add(externalForce);\r
+\r
+ // Mass of vertex\r
+ let M = this.vertexWeights[vertexIndex];\r
+ // constant gravity\r
+ let g = new THREE.Vector3(0, -9.8, 0);\r
+ // stiffness\r
+ let k = 1000;\r
+\r
+ // Wind vector\r
+ let fWind = new THREE.Vector3(\r
+ this.windFactor.x * (Math.sin(vertex.x * vertex.y * this.time)+1),\r
+ this.windFactor.y * Math.cos(vertex.z * this.time),\r
+ this.windFactor.z * Math.sin(Math.cos(5 * vertex.x * vertex.y * vertex.z))\r
+ );\r
+ //console.log(fWind);\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 = 0.1;\r
+ \r
+ let velocity = new THREE.Vector3(\r
+ (this.previousPositions[vertexIndex].x - vertex.x) / dt,\r
+ (this.previousPositions[vertexIndex].y - vertex.y) / dt,\r
+ (this.previousPositions[vertexIndex].z - vertex.z) / dt\r
+ );\r
+\r
+ //console.log(velocity, vertex, this.previousPositions[vertexIndex]);\r
+\r
+ let fAirResistance = velocity.multiply(velocity).multiplyScalar(-a);\r
+ \r
+ let springSum = new THREE.Vector3(0, 0, 0);\r
+\r
+ // Get the bounding springs and add them to the needed springs\r
+ // TODO: optimize\r
+\r
+ const numPointsX = this.numPointsWidth;\r
+ const numPointsY = this.numPointsHeight;\r
+ const numFacesX = numPointsX - 1;\r
+ const numFacesY = numPointsY - 1;\r
+\r
+ function getFaceIndex(x, y) {\r
+ return y * numFacesX + x;\r
+ }\r
+\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
+ 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
+ result.multiplyScalar(M).multiply(g).add(fWind).add(externalForce).add(fAirResistance).sub(springSum);\r
+\r
+ document.getElementById("Output").innerText = "SpringSum: " + Math.floor(springSum.y);\r
+\r
+ let threshold = 1;\r
+ let forceReduktion = 0.8;\r
+ if(Math.abs(externalForce.z) > threshold){\r
+ externalForce.z *= forceReduktion;\r
+ } else {\r
+ externalForce.z = 0;\r
+ }\r
+\r
+ if(Math.abs(externalForce.y) > threshold){\r
+ externalForce.y *= forceReduktion;\r
+ } else {\r
+ externalForce.y = 0;\r
+ }\r
+\r
+ if(Math.abs(externalForce.x) > threshold){\r
+ externalForce.x *= forceReduktion;\r
+ } else {\r
+ externalForce.x = 0;\r
+ }\r
+ \r
+ \r
+\r
+ return result;\r
+}\r
+\r
+/**\r
+ * The Verlet algorithm as an integrator \r
+ * to get the next position of a vertex \r
+ * @param {Vector3} currentPosition \r
+ * @param {Vector3} previousPosition \r
+ * @param {Vector3} acceleration \r
+ * @param {number} passedTime The delta time since last frame\r
+ */\r
+verlet(currentPosition, previousPosition, acceleration, passedTime) {\r
+ // verlet algorithm\r
+ // 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
+ const DRAG = 0.97;\r
+ let nextPosition = new THREE.Vector3(\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
+euler(currentPosition, acceleration, passedTime) {\r
+ let nextPosition = new THREE.Vector3(\r
+ currentPosition.x + acceleration.x * passedTime,\r
+ currentPosition.y + acceleration.y * passedTime,\r
+ currentPosition.z + acceleration.z * passedTime,\r
+ );\r
+\r
+ return nextPosition;\r
+}\r
+\r
+wind(intersects) {\r
+ let intersect = intersects[0];\r
+ this.externalForces[intersect.face.a].z -= this.windForce;\r
+ this.externalForces[intersect.face.b].z -= this.windForce;\r
+ this.externalForces[intersect.face.c].z -= this.windForce;\r
+}\r
+\r
+mousePressed = false;\r
+mouseMoved = false;\r
+intersects;\r
+\r
+mousePress(intersects){\r
+ this.mousePressed = true;\r
+ this.intersects = intersects;\r
+\r
+}\r
+\r
+mouseMove(mousePos){\r
+ this.mouseMoved = true;\r
+ if(this.mousePressed){\r
+ let intersect = this.intersects[0];\r
+ this.externalForces[intersect.face.a].add(mousePos.clone().sub(this.geometry.vertices[intersect.face.a]).multiplyScalar(90));\r
+ /*\r
+ this.geometry.vertices[intersect.face.a].x = mousePos.x;\r
+ this.geometry.vertices[intersect.face.a].y = mousePos.y;\r
+ this.geometry.vertices[intersect.face.a].z = mousePos.z;\r
+ */ \r
+ }\r
+}\r
+\r
+mouseRelease(){\r
+ this.mousePressed = false;\r
+}\r
+\r
+}\r
+\r
projects / cloth_sim / blobdiff