Viewing Program

Program Data

Program thumbnail for "{props.program.title}"

Title	First Person Wave Simulation (Contest Entry)
ID	6067712357236736
Created	8 years ago, 1511630862131
Updated	8 years ago, 1511662535492
Code	/** * This is my entry for the following contest, * which I encourage you all to check out: * * https://www.khanacademy.org/computer-programming/contest-cool-graphic/5037613524647936 */ // Lowering this gives a larger field of view. var SCALE = 750; Array.zeros = function(n, m) { / Create an m by n array of zeros. / var row; var arr = []; for (var j = 0; j < n; j ++) { row = []; for (var i = 0; i < m; i ++) { row.push(0); } arr.push(row); } return arr; }; Array.linspace = function(a, b, n) { / Uniform partition of [a, b] using n points. / var p = []; var h = (b - a)/(n - 1); for (var i = 0; i < n; i ++) { p.push(a + ih); } return p; }; var cam = { // Position. x: 0, y: 0, z: 0, // Orientation. u: Math.PI, v: 0, minV: -Math.PI/2, maxV: Math.PI/2 }; cam.move = function(dx, dy, dz) { /* Move the camera (position). / this.x += dx; this.y += dy; this.z += dz; }; cam.turn = function(du, dv) { / Move the camera (orientation). / this.u += du; this.v = constrain(this.v + dv, this.minV, this.maxV); this.cu = Math.cos(this.u); this.su = Math.sin(this.u); this.cv = Math.cos(this.v); this.sv = Math.sin(this.v); this.cucv = this.cu this.cv; this.cusv = this.cu * this.sv; this.sucv = this.su * this.cv; this.susv = this.su * this.sv; }; cam.inView = function(x, y, z) { /* Check if the given point is in view of the camera. / return ((x - this.x)this.cucv + (y - this.y)this.sucv + (z - this.z)this.sv) >= 0; }; cam.inViewPt = function(pt) { /* Check if the given point is in view of the camera. / return ((pt[0] - this.x)this.cucv + (pt[1] - this.y)this.sucv + (pt[2] - this.z)this.sv) >= 0; }; cam.dist = function(x, y, z) { /* The distance from the point to the camera plane. / return Math.abs( (x - this.x)this.cucv + (y - this.y)this.sucv + (z - this.z)this.sv ); }; cam.distPt = function(pt) { /* The distance from the point to the camera plane. / return Math.abs( (pt[0] - this.x)this.cucv + (pt[1] - this.y)this.sucv + (pt[2] - this.z)this.sv ); }; cam.proj = function(x, y, z) { /* Project the point onto the camera plane. / var dx = x - this.x; var dy = y - this.y; var dz = z - this.z; var d = Math.abs( dxthis.cucv + dythis.sucv + dzthis.sv ); return [ (this.sudx - this.cudy)/d, (this.cvdz - this.cusvdx - this.susvdy)/d ]; }; cam.projPt = function(pt) { / Project the point onto the camera plane. / var dx = pt[0] - this.x; var dy = pt[1] - this.y; var dz = pt[2] - this.z; var d = Math.abs( dxthis.cucv + dythis.sucv + dzthis.sv ); return [ (this.sudx - this.cudy)/d, (this.cvdz - this.cusvdx - this.susvdy)/d ]; }; var canvas = { origin: [200, 200], scale: SCALE }; canvas.coords = function(x, y) { / Map the point to the screen's coordinate system. / return [ this.origin[0] + this.scale x, this.origin[1] - this.scale * y ]; }; canvas.coordsPt = function(pt) { /* Map the point to the screen's coordinate system. / return [ this.origin[0] + this.scale pt[0], this.origin[1] - this.scale * pt[1] ]; }; canvas.proj = function(x, y, z) { /* Project the point to the screen's coordinate system. / return this.coordsPt(cam.proj(x, y, z)); }; canvas.projPt = function(pt) { / Project the point to the screen's coordinate system. / return this.coordsPt(cam.projPt(pt)); }; canvas.quad = function(a, b, c, d) { / Project a quad in 3D onto the screen's coordinate system. / var ca = canvas.projPt(a); var cb = canvas.projPt(b); var cc = canvas.projPt(c); var cd = canvas.projPt(d); quad(ca[0], ca[1], cb[0], cb[1], cc[0], cc[1], cd[0], cd[1]); }; / Camera parameters. / var deg = Math.PI/180; var camDt = 1/30; var acc = 0.15; var vel = new PVector(0, 0, 0); var angAcc = 9deg; var angVel = new PVector(0, 0); var keys = []; var keyPressed = function() { keys[keyCode] = true; }; var keyReleased = function() { keys[keyCode] = false; }; /* Simulation parameters. / // Wall. var wallN = 10; var wallI = Array.linspace(-1, 1, wallN + 1); // "Light source". var light = [0, 0, 0.35]; // Wave decay parameter. var a = 0.01; // Wave propagation speed. var c = 0.75; // Domain: [ax,bx]x[ay,by]. var ax = -1; var bx = 1; var ay = -1; var by = 1; // Simulation time step. var dt = 0.015; // Grid resolution. var M = 30; // x-direction. var N = 30; // y-direction. var dx = (bx - ax)/(M + 1); var dy = (by - ay)/(N + 1); var dxh = 0.5dx; var dyh = 0.5dy; // Initial wave profile. var initialProfile = function(x, y) { var r1 = sq(x - 0.25) + sq(y - 0.3); var r2 = sq(x + 0.25) + sq(y + 0.4); return 0.10 Math.sin(8 * Math.PI * Math.sqrt(r1))/(1 + 25r1) + 0.08 Math.sin(4 * Math.PI * Math.sqrt(r2))/(1 + 15r2); }; / Simulation setup. / var tdt = 2dt; var Ix = Array.linspace(ax, bx, M + 2); var Iy = Array.linspace(ay, by, N + 2); var ctx = Math.pow(cdt/dx, 2); var cty = Math.pow(cdt/dy, 2); var adt2 = adt/2; var coef = 1/(1 + adt2); var coef2 = adt2 - 1; var coef3 = 2(1 - ctx - cty); var u = Array.zeros(N + 2, M + 2); var v = Array.zeros(N + 2, M + 2); var w = Array.zeros(N + 2, M + 2); var LOW = -1; var HIGH = 1; var start; var elapsed; var time = -dt; var fps; var fpsDelta; var fpsRefresh = 10; var fpsStart = millis(); var faces = []; var init = function() { frameRate(30); colorMode(HSB); textFont(createFont("monospace", 12)); cam.turn(65deg, -18deg); cam.move(0.9, 2.0, 0.9); vel = new PVector( -3cam.cucv, -3cam.sucv, -3cam.sv ); angVel = new PVector( 10deg, 5deg ); // Initial wave profile. for (var i = 0; i <= M + 1; i ++) { for (var j = 0; j <= N + 1; j ++) { v[j][i] = initialProfile(Ix[i], Iy[j]); w[j][i] = initialProfile(Ix[i], Iy[j]); } } start = millis(); }; var handleTimers = function() { / Handle fps and other timers. / if (frameCount % fpsRefresh === 0) { fpsDelta = 0.001 (millis() - fpsStart); fps = Math.round(fpsRefresh/fpsDelta); fpsStart = millis(); } time += dt; elapsed = 0.001 * (millis() - start); }; var handleCamera = function() { /* Handle the physics of moving and turning the camera. / if (keys[87]) { // W vel.x += acccam.cu; vel.y += acccam.su; } if (keys[65]) { // A vel.x -= acccam.su; vel.y += acccam.cu; } if (keys[83]) { // S vel.x -= acccam.cu; vel.y -= acccam.su; } if (keys[68]) { // D vel.x += acccam.su; vel.y -= acccam.cu; } if (keys[81]) { // Q vel.z += acc; } if (keys[69]) { // E vel.z -= acc; } if (keys[UP]) { // UP angVel.y += angAcc; } if (keys[LEFT]) { // LEFT angVel.x += angAcc; } if (keys[DOWN]) { // DOWN angVel.y -= angAcc; } if (keys[RIGHT]) { // RIGHT angVel.x -= angAcc; } var vdt = PVector.mult(vel, camDt); cam.move(vdt.x, vdt.y, vdt.z); vel.mult(0.90); var adt = PVector.mult(angVel, camDt); cam.turn(adt.x, adt.y); angVel.mult(0.90); }; var solveAndPush = function() { / Compute the next time step. / for (var i = 1; i <= M; i ++) { for (var j = 1; j <= N; j ++) { w[j][i] = coef ( coef2u[j][i] + coef3v[j][i] + ctx(v[j][i+1] + v[j][i-1]) + cty(v[j+1][i] + v[j-1][i]) ); } } for (var i = 0; i <= M + 1; i ++) { for (var j = 0; j <= N + 1; j ++) { u[j][i] = v[j][i]; v[j][i] = w[j][i]; } } }; var cmp = function(f1, f2) { /* Compare the distance of the faces to the camera plane. / return cam.dist( f2[0][0] + dxh, f2[0][1] + dyh, 0.25 (f2[0][2] + f2[1][2] + f2[2][2] + f2[3][2])) - cam.dist( f1[0][0] + dxh, f1[0][1] + dyh, 0.25 * (f1[0][2] + f1[1][2] + f1[2][2] + f1[3][2]) ); }; var pushFaces = function() { /* Compute and push faces into array. / // This can probably be done more efficiently. for (var i = 0; i <= M; i ++) { for (var j = 0; j <= N; j ++) { faces.push([ [Ix[i], Iy[j], w[j][i] ], [Ix[i+1], Iy[j], w[j][i+1] ], [Ix[i+1], Iy[j+1], w[j+1][i+1]], [Ix[i], Iy[j+1], w[j+1][i] ] ]); } } for (var i = 0; i < wallN; i ++) { for (var j = 0; j < wallN; j ++) { faces.push([ [0, wallI[i], wallI[j]], [0, wallI[i+1], wallI[j]], [0, wallI[i+1], wallI[j+1]], [0, wallI[i], wallI[j+1]] ]); } } }; var drawFaces = function() { var c, d; var face; strokeWeight(1); for (var i = 0; i < faces.length; i ++) { face = faces[i]; // Temporary solution... if (!(cam.inViewPt(face[0]) && cam.inViewPt(face[1]) && cam.inViewPt(face[2]) && cam.inViewPt(face[3]))) { continue; } d = Math.pow( sq(face[0][0] - light[0]) + sq(face[0][1] - light[1]) + sq(face[0][2] - light[2]), 0.25 ); c = color( map(constrain(face[0][2], LOW, HIGH), LOW, HIGH, 90, 180), 190, map(constrain(4/d, 0, 20), 0, 5, 50, 255) ); fill(c); stroke(c); canvas.quad(face[0], face[1], face[2], face[3]); } }; var drawInfo = function() { / Debug info on screen. */ fill(30); text(" WASD : move", 20, 20); text("ARROWS: look around", 20, 35); text("Q or E: fly up or down", 20, 50); text(" iter: " + frameCount, 10, 445); text(" time: " + time.toFixed(3), 10, 460); text("elapsed: " + elapsed.toFixed(1), 10, 475); text(" fps: " + fps, 10, 490); text("x: " + cam.x.toFixed(2), 140, 460); text("y: " + cam.y.toFixed(2), 140, 475); text("z: " + cam.z.toFixed(2), 140, 490); text("u: " + ((cam.u/deg) % 360).toFixed(1) + "°", 217, 475); text("v: " + (cam.v/deg).toFixed(1) + "°", 217, 490); }; init(); var draw = function() { background(138, 100, 240); handleTimers(); handleCamera(); solveAndPush(); pushFaces(); faces.sort(cmp); drawFaces(); drawInfo(); faces = []; };
Folds	11,23,25,33,36,48,50,55,57,71,73,77,79,83,85,92,94,101,103,119,121,137,140,143,145,151,153,159,161,164,166,169,171,178,308,318,320,373,375,393,395,406,408,433,435,468,470,489
Fork	false
Key	ag5zfmtoYW4tYWNhZGVteXIXCxIKU2NyYXRjaHBhZBiAgJz91dHjCgw
Votes	235
Spin-Offs	13
Type	PJS
Width	500
Height	500
User Flagged	false
Origin Scratchpad	{"id":"5037613524647936","title":"[RESULTS] Contest: Cool Graphic","deleted":"false","official":"false"}
Hidden From Hotlist	false
Restricted Posting	false
By Child	false
Author Nick	Qeeko
Author Name	Qeeko
Author ID	kaid_656542968054661279010009
Author Profile Access	PUBLIC

Archive Data

Added	10 months ago, 1739453136680
Updated	10 months ago, 1739453146745
Source Deleted	unknown