X-Git-Url: https://gitweb.ps.run/cloth_sim/blobdiff_plain/56f6324db4aa55946a6b5ef7de3e1df8b0e22bca..959c350fb8cddf7d1b31907fcc1f7f99dad52f3e:/Scripts/cloth.js diff --git a/Scripts/cloth.js b/Scripts/cloth.js deleted file mode 100644 index aaa9d24..0000000 --- a/Scripts/cloth.js +++ /dev/null @@ -1,228 +0,0 @@ -const DAMPING = 0.03; -const DRAG = 1 - DAMPING; -const MASS = 0.35; -const GRAVITY = new THREE.Vector3(0, -9.81 * MASS, 0); -const K = 1; - -const options = { - wind: true, -}; - -class Constraint { - constructor(p1, p2, restDist) { - this.p1 = p1; - this.p2 = p2; - 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)); - const correction = diff.multiplyScalar((currentDist - this.restDist) / currentDist); - correction.multiplyScalar(K); - correction.clampLength(0, 1); - const correctionHalf = correction.multiplyScalar(0.5); - if (this.p1.movable && this.p2.movable) { - this.p1.position.add(correctionHalf); - this.p2.position.sub(correctionHalf); - } else if (! this.p1.movable && this.p2.movable) { - this.p2.position.sub(correction); - } else if (this.p1.movable && ! this.p2.movable) { - this.p1.position.add(correction); - } - } -} - -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); - this.acceleration = new THREE.Vector3(0, 0, 0); - 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)); - - if (this.movable) { - this.previous = this.position; - this.position = nextPosition; - } - - this.acceleration.set(0, 0, 0); - } -} - -class Cloth { - constructor(width, height, numPointsWidth, numPointsHeight) { - this.width = width; - this.height = height; - this.numPointsWidth = numPointsWidth; - this.numPointsHeight = numPointsHeight; - this.windFactor = new THREE.Vector3(5, 2, 2); - - /** - * distance between two vertices horizontally/vertically - * divide by the number of points minus one - * because there are (n - 1) lines between n vertices - */ - let stepWidth = width / (numPointsWidth - 1); - let stepHeight = height / (numPointsHeight - 1); - - /** - * iterate over the number of vertices in x/y axis - * and add a new Particle to "particles" - */ - this.particles = []; - for (let y = 0; y < numPointsHeight; y++) { - for (let x = 0; x < numPointsWidth; x++) { - this.particles.push( - new Particle( - (x - ((numPointsWidth-1)/2)) * stepWidth, - height - (y + ((numPointsHeight-1)/2)) * stepHeight, - 0, - MASS) - ); - } - } - - //this.particles[this.getVertexIndex(0, 0)].movable = false; - const n = 3; - for (let i = 0; i <= n; i++) - this.particles[this.getVertexIndex(0, Math.floor((numPointsHeight-1)*(i/n)))].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); - - /** - * generate constraints (springs) - */ - this.constraints = []; - for (let y = 0; y < numPointsHeight; y++) { - for (let x = 0; x < numPointsWidth; x++) { - if (x < numPointsWidth-1) { - this.constraints.push(new Constraint( - this.particles[this.getVertexIndex(x, y)], - this.particles[this.getVertexIndex(x+1, y)], - REST_DIST_X - )); - } - if (y < numPointsHeight-1) { - this.constraints.push(new Constraint( - this.particles[this.getVertexIndex(x, y)], - this.particles[this.getVertexIndex(x, y+1)], - REST_DIST_Y - )); - } - } - } - } - generateGeometry() { - const geometry = new THREE.BufferGeometry(); - - const vertices = []; - const normals = []; - const indices = []; - - for (let particle of this.particles) { - vertices.push( - particle.position.x, - particle.position.y, - particle.position.z); - } - - const numPointsWidth = this.numPointsWidth; - const numPointsHeight = this.numPointsHeight; - - /** - * generate faces based on 4 vertices - * and 6 springs each - */ - for (let y = 0; y < numPointsHeight - 1; y++) { - for (let x = 0; x < numPointsWidth - 1; x++) { - indices.push( - this.getVertexIndex(x, y), - this.getVertexIndex(x+1, y), - this.getVertexIndex(x+1, y+1) - ); - indices.push( - this.getVertexIndex(x, y), - this.getVertexIndex(x+1, y+1), - this.getVertexIndex(x, y+1) - ); - } - } - - geometry.setIndex(indices); - geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3)); - //geometry.setAttribute('normal', new THREE.Float32BufferAttribute(normals, 3)); - geometry.computeBoundingSphere(); - geometry.computeVertexNormals(); - - return geometry; - } - updateGeometry(geometry) { - const positions = geometry.attributes.position.array; - for (let i in this.particles) { - let p = this.particles[i]; - positions[i*3+0] = p.position.x; - positions[i*3+1] = p.position.y; - positions[i*3+2] = p.position.z; - } - geometry.attributes.position.needsUpdate = true; - geometry.computeBoundingSphere(); - geometry.computeVertexNormals(); - } - 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? - if (options.wind) - 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 - * in "vertices" array based on its x and y positions - * in the mesh - * @param {number} x - x index of vertex - * @param {number} y - y index of vertex - */ - getVertexIndex(x, y) { - return y * this.numPointsWidth + x; - } -} \ No newline at end of file