-/**\r
- * Convenience Function for calculating the distance between two vectors\r
- * because THREE JS Vector functions mutate variables\r
- * @param {Vector3} a - Vector A\r
- * @param {Vector3} b - Vector B\r
- */\r
-function vectorLength(a, b) {\r
- let v1 = new THREE.Vector3();\r
- v1.copy(a);\r
- let v2 = new THREE.Vector3();\r
- v2.copy(b);\r
-\r
- return v1.sub(v2).length();\r
-}\r
-\r
-/**\r
- * Class representing a quad face\r
- * Each face consists of two triangular mesh faces\r
- * containts four indices for determining vertices\r
- * and six springs, one between each of the vertices\r
- */\r
-export class Face {\r
- a;\r
- b;\r
- c;\r
- d;\r
-\r
- springs = [];\r
-\r
- constructor(a, b, c, d) {\r
- this.a = a;\r
- this.b = b;\r
- this.c = c;\r
- this.d = d;\r
- }\r
-}\r
-\r
-/**\r
- * Class representing a single spring\r
- * has a current and resting length\r
- * and indices to the two connected vertices\r
- */\r
-export class Spring {\r
- restLength;\r
- currentLength;\r
- index1;\r
- index2;\r
-\r
-\r
- /**\r
- * set vertex indices\r
- * and calculate inital length based on the\r
- * vertex positions\r
- * @param {Array<Vector3>} vertices \r
- * @param {number} index1 \r
- * @param {number} index2 \r
- */\r
- constructor(vertices, index1, index2) {\r
- this.index1 = index1;\r
- this.index2 = index2;\r
-\r
- let length = vectorLength(vertices[index1], vertices[index2]);\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
- * Class representing a single piece of cloth\r
- * contains THREE JS geometry,\r
- * logically represented by an array of adjacent faces\r
- * and vertex weights which are accessed by the same\r
- * indices as the vertices in the Mesh\r
- */\r
-export class Cloth {\r
- VertexWeight = 1;\r
-\r
- geometry = new THREE.Geometry();\r
-\r
- faces = [];\r
-\r
- vertexWeights = [];\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
- * and the number of vertices it should be composed of\r
- * @param {number} width - width of the cloth\r
- * @param {number} height - height of the cloth\r
- * @param {number} numPointsWidth - number of vertices in horizontal direction\r
- * @param {number} numPointsHeight - number of vertices in vertical direction\r
- */\r
- createBasic(width, height, numPointsWidth, numPointsHeight) {\r
- /** resulting vertices and faces */\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
- * because there are (n - 1) lines between n vertices\r
- */\r
- let stepWidth = width / (numPointsWidth - 1);\r
- let stepHeight = height / (numPointsHeight - 1);\r
-\r
- /**\r
- * iterate over the number of vertices in x/y axis\r
- * and add a new Vector3 to "vertices"\r
- */\r
- for (let y = 0; y < numPointsHeight; y++) {\r
- for (let x = 0; x < numPointsWidth; x++) {\r
- vertices.push(\r
- new THREE.Vector3((x - ((numPointsWidth-1)/2)) * stepWidth, height - (y + ((numPointsHeight-1)/2)) * stepHeight, 0)\r
- );\r
- }\r
- }\r
-\r
- /**\r
- * helper function to calculate index of vertex\r
- * in "vertices" array based on its x and y positions\r
- * in the mesh\r
- * @param {number} x - x index of vertex\r
- * @param {number} y - y index of vertex\r
- */\r
- function getVertexIndex(x, y) {\r
- return y * numPointsWidth + x;\r
- }\r
-\r
- /**\r
- * generate faces based on 4 vertices\r
- * and 6 springs each\r
- */\r
- for (let y = 0; y < numPointsHeight - 1; y++) {\r
- for (let x = 0; x < numPointsWidth - 1; x++) {\r
- let newFace = new Face(\r
- getVertexIndex(x, y),\r
- getVertexIndex(x, y + 1),\r
- getVertexIndex(x + 1, y),\r
- getVertexIndex(x + 1, y + 1),\r
- );\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
-\r
- /**\r
- * call createExplicit\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
- * Generate THREE JS Geometry\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<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].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
- * generate two triangles per face,\r
- * calculate weight of face as its area\r
- * and split between the 4 vertices\r
- */\r
- for (let i in faces) {\r
- let face = faces[i];\r
-\r
- /** copy faces to class member */\r
- this.faces.push(face);\r
-\r
- /** generate triangles */\r
- this.geometry.faces.push(new THREE.Face3(\r
- face.a, face.b, face.c\r
- ));\r
- this.geometry.faces.push(new THREE.Face3(\r
- face.c, face.b, face.d\r
- ));\r
-\r
- /**\r
- * calculate area of face as combined area of\r
- * its two composing triangles\r
- */\r
- let xLength = vectorLength(this.geometry.vertices[face.b], this.geometry.vertices[face.a]);\r
- let yLength = vectorLength(this.geometry.vertices[face.c], this.geometry.vertices[face.a]);\r
- let weight = xLength * yLength / 2;\r
-\r
- xLength = vectorLength(this.geometry.vertices[face.b], this.geometry.vertices[face.d]);\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
- this.vertexWeights[face.a] += weight / 4;\r
- this.vertexWeights[face.b] += weight / 4;\r
- this.vertexWeights[face.c] += weight / 4;\r
- this.vertexWeights[face.d] += weight / 4;\r
- }\r
-\r
- /**\r
- * let THREE JS compute bounding sphere around generated mesh\r
- * needed for View Frustum Culling internally\r
- */\r
- this.geometry.computeBoundingSphere();\r
- this.geometry.computeFaceNormals();\r
- this.geometry.computeVertexNormals();\r
- }\r
-\r
- /**\r
- * generate a debug mesh for visualizing\r
- * vertices and springs of the cloth\r
- * and add it to scene for rendering\r
- * @param {Scene} scene - Scene to add Debug Mesh to\r
- */\r
- createDebugMesh(scene) {\r
- /**\r
- * helper function to generate a single line\r
- * between two Vertices with a given color\r
- * @param {Vector3} from \r
- * @param {Vector3} to \r
- * @param {number} color \r
- */\r
- function addLine(from, to, color) {\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 line = new THREE.Line(geometry, material);\r
- line.renderOrder = 1;\r
- scene.add(line);\r
- }\r
- /**\r
- * helper function to generate a small sphere\r
- * at a given Vertex Position with color\r
- * @param {Vector3} point \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
- sphere.position.set(point.x, point.y, point.z);\r
- scene.add(sphere);\r
- }\r
-\r
- let lineColor = 0x000000;\r
- let pointColor = 0xff00000;\r
-\r
- /**\r
- * generate one line for each of the 6 springs\r
- * and one point for each of the 4 vertices\r
- * for all of the faces\r
- */\r
- for (let i in this.faces) {\r
- let face = this.faces[i];\r
- addLine(this.geometry.vertices[face.a], this.geometry.vertices[face.b], lineColor);\r
- addLine(this.geometry.vertices[face.a], this.geometry.vertices[face.c], lineColor);\r
- addLine(this.geometry.vertices[face.a], this.geometry.vertices[face.d], lineColor);\r
- addLine(this.geometry.vertices[face.b], this.geometry.vertices[face.c], lineColor);\r
- addLine(this.geometry.vertices[face.b], this.geometry.vertices[face.d], lineColor);\r
- addLine(this.geometry.vertices[face.c], this.geometry.vertices[face.d], lineColor);\r
-\r
- addPoint(this.geometry.vertices[face.a], pointColor);\r
- addPoint(this.geometry.vertices[face.b], pointColor);\r
- addPoint(this.geometry.vertices[face.c], pointColor);\r
- addPoint(this.geometry.vertices[face.d], pointColor);\r
- }\r
- }\r
-\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
+// cloth rendering\r
+// simulate\r
+// setup scene\r
+// orbit controls/skybox/flagge
\ No newline at end of file
projects / cloth_sim / blobdiff