The Tor Browser / file revision

 /**

  * Copyright 2012 the V8 project authors. All rights reserved.

  * Copyright 2009 Oliver Hunt <http://nerget.com>

  *

  * Permission is hereby granted, free of charge, to any person

  * obtaining a copy of this software and associated documentation

  * files (the "Software"), to deal in the Software without

  * restriction, including without limitation the rights to use,

  * copy, modify, merge, publish, distribute, sublicense, and/or sell

  * copies of the Software, and to permit persons to whom the

  * Software is furnished to do so, subject to the following

  * conditions:

  *

  * The above copyright notice and this permission notice shall be

  * included in all copies or substantial portions of the Software.

  *

  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

  * OTHER DEALINGS IN THE SOFTWARE.

  */

 var NavierStokes = new BenchmarkSuite('NavierStokes', 1484000,

                                       [new Benchmark('NavierStokes',

                                                      runNavierStokes,

                                                      setupNavierStokes,

                                                      tearDownNavierStokes)]);

 var solver = null;

 function runNavierStokes()

 {

     solver.update();

 }

 function setupNavierStokes()

 {

     solver = new FluidField(null);

     solver.setResolution(128, 128);

     solver.setIterations(20);

     solver.setDisplayFunction(function(){});

     solver.setUICallback(prepareFrame);

     solver.reset();

 }

 function tearDownNavierStokes()

 {

     solver = null;

 }

 function addPoints(field) {

     var n = 64;

     for (var i = 1; i <= n; i++) {

         field.setVelocity(i, i, n, n);

         field.setDensity(i, i, 5);

         field.setVelocity(i, n - i, -n, -n);

         field.setDensity(i, n - i, 20);

         field.setVelocity(128 - i, n + i, -n, -n);

         field.setDensity(128 - i, n + i, 30);

     }

 }

 var framesTillAddingPoints = 0;

 var framesBetweenAddingPoints = 5;

 function prepareFrame(field)

 {

     if (framesTillAddingPoints == 0) {

         addPoints(field);

         framesTillAddingPoints = framesBetweenAddingPoints;

         framesBetweenAddingPoints++;

     } else {

         framesTillAddingPoints--;

     }

 }

 // Code from Oliver Hunt (http://nerget.com/fluidSim/pressure.js) starts here.

 function FluidField(canvas) {

     function addFields(x, s, dt)

     {

         for (var i=0; i<size ; i++ ) x[i] += dt*s[i];

     }

     function set_bnd(b, x)

     {

         if (b===1) {

             for (var i = 1; i <= width; i++) {

                 x[i] =  x[i + rowSize];

                 x[i + (height+1) *rowSize] = x[i + height * rowSize];

             }

             for (var j = 1; i <= height; i++) {

                 x[j * rowSize] = -x[1 + j * rowSize];

                 x[(width + 1) + j * rowSize] = -x[width + j * rowSize];

             }

         } else if (b === 2) {

             for (var i = 1; i <= width; i++) {

                 x[i] = -x[i + rowSize];

                 x[i + (height + 1) * rowSize] = -x[i + height * rowSize];

             }

             for (var j = 1; j <= height; j++) {

                 x[j * rowSize] =  x[1 + j * rowSize];

                 x[(width + 1) + j * rowSize] =  x[width + j * rowSize];

             }

         } else {

             for (var i = 1; i <= width; i++) {

                 x[i] =  x[i + rowSize];

                 x[i + (height + 1) * rowSize] = x[i + height * rowSize];

             }

             for (var j = 1; j <= height; j++) {

                 x[j * rowSize] =  x[1 + j * rowSize];

                 x[(width + 1) + j * rowSize] =  x[width + j * rowSize];

             }

         }

         var maxEdge = (height + 1) * rowSize;

         x[0]                 = 0.5 * (x[1] + x[rowSize]);

         x[maxEdge]           = 0.5 * (x[1 + maxEdge] + x[height * rowSize]);

         x[(width+1)]         = 0.5 * (x[width] + x[(width + 1) + rowSize]);

         x[(width+1)+maxEdge] = 0.5 * (x[width + maxEdge] + x[(width + 1) + height * rowSize]);

     }

     function lin_solve(b, x, x0, a, c)

     {

         if (a === 0 && c === 1) {

             for (var j=1 ; j<=height; j++) {

                 var currentRow = j * rowSize;

                 ++currentRow;

                 for (var i = 0; i < width; i++) {

                     x[currentRow] = x0[currentRow];

                     ++currentRow;

                 }

             }

             set_bnd(b, x);

         } else {

             var invC = 1 / c;

             for (var k=0 ; k<iterations; k++) {

                 for (var j=1 ; j<=height; j++) {

                     var lastRow = (j - 1) * rowSize;

                     var currentRow = j * rowSize;

                     var nextRow = (j + 1) * rowSize;

                     var lastX = x[currentRow];

                     ++currentRow;

                     for (var i=1; i<=width; i++)

                         lastX = x[currentRow] = (x0[currentRow] + a*(lastX+x[++currentRow]+x[++lastRow]+x[++nextRow])) * invC;

                 }

                 set_bnd(b, x);

             }

         }

     }

     function diffuse(b, x, x0, dt)

     {

         var a = 0;

         lin_solve(b, x, x0, a, 1 + 4*a);

     }

     function lin_solve2(x, x0, y, y0, a, c)

     {

         if (a === 0 && c === 1) {

             for (var j=1 ; j <= height; j++) {

                 var currentRow = j * rowSize;

                 ++currentRow;

                 for (var i = 0; i < width; i++) {

                     x[currentRow] = x0[currentRow];

                     y[currentRow] = y0[currentRow];

                     ++currentRow;

                 }

             }

             set_bnd(1, x);

             set_bnd(2, y);

         } else {

             var invC = 1/c;

             for (var k=0 ; k<iterations; k++) {

                 for (var j=1 ; j <= height; j++) {

                     var lastRow = (j - 1) * rowSize;

                     var currentRow = j * rowSize;

                     var nextRow = (j + 1) * rowSize;

                     var lastX = x[currentRow];

                     var lastY = y[currentRow];

                     ++currentRow;

                     for (var i = 1; i <= width; i++) {

                         lastX = x[currentRow] = (x0[currentRow] + a * (lastX + x[currentRow] + x[lastRow] + x[nextRow])) * invC;

                         lastY = y[currentRow] = (y0[currentRow] + a * (lastY + y[++currentRow] + y[++lastRow] + y[++nextRow])) * invC;

                     }

                 }

                 set_bnd(1, x);

                 set_bnd(2, y);

             }

         }

     }

     function diffuse2(x, x0, y, y0, dt)

     {

         var a = 0;

         lin_solve2(x, x0, y, y0, a, 1 + 4 * a);

     }

     function advect(b, d, d0, u, v, dt)

     {

         var Wdt0 = dt * width;

         var Hdt0 = dt * height;

         var Wp5 = width + 0.5;

         var Hp5 = height + 0.5;

         for (var j = 1; j<= height; j++) {

             var pos = j * rowSize;

             for (var i = 1; i <= width; i++) {

                 var x = i - Wdt0 * u[++pos];

                 var y = j - Hdt0 * v[pos];

                 if (x < 0.5)

                     x = 0.5;

                 else if (x > Wp5)

                     x = Wp5;

                 var i0 = x | 0;

                 var i1 = i0 + 1;

                 if (y < 0.5)

                     y = 0.5;

                 else if (y > Hp5)

                     y = Hp5;

                 var j0 = y | 0;

                 var j1 = j0 + 1;

                 var s1 = x - i0;

                 var s0 = 1 - s1;

                 var t1 = y - j0;

                 var t0 = 1 - t1;

                 var row1 = j0 * rowSize;

                 var row2 = j1 * rowSize;

                 d[pos] = s0 * (t0 * d0[i0 + row1] + t1 * d0[i0 + row2]) + s1 * (t0 * d0[i1 + row1] + t1 * d0[i1 + row2]);

             }

         }

         set_bnd(b, d);

     }

     function project(u, v, p, div)

     {

         var h = -0.5 / Math.sqrt(width * height);

         for (var j = 1 ; j <= height; j++ ) {

             var row = j * rowSize;

             var previousRow = (j - 1) * rowSize;

             var prevValue = row - 1;

             var currentRow = row;

             var nextValue = row + 1;

             var nextRow = (j + 1) * rowSize;

             for (var i = 1; i <= width; i++ ) {

                 div[++currentRow] = h * (u[++nextValue] - u[++prevValue] + v[++nextRow] - v[++previousRow]);

                 p[currentRow] = 0;

             }

         }

         set_bnd(0, div);

         set_bnd(0, p);

         lin_solve(0, p, div, 1, 4 );

         var wScale = 0.5 * width;

         var hScale = 0.5 * height;

         for (var j = 1; j<= height; j++ ) {

             var prevPos = j * rowSize - 1;

             var currentPos = j * rowSize;

             var nextPos = j * rowSize + 1;

             var prevRow = (j - 1) * rowSize;

             var currentRow = j * rowSize;

             var nextRow = (j + 1) * rowSize;

             for (var i = 1; i<= width; i++) {

                 u[++currentPos] -= wScale * (p[++nextPos] - p[++prevPos]);

                 v[currentPos]   -= hScale * (p[++nextRow] - p[++prevRow]);

             }

         }

         set_bnd(1, u);

         set_bnd(2, v);

     }

     function dens_step(x, x0, u, v, dt)

     {

         addFields(x, x0, dt);

         diffuse(0, x0, x, dt );

         advect(0, x, x0, u, v, dt );

     }

     function vel_step(u, v, u0, v0, dt)

     {

         addFields(u, u0, dt );

         addFields(v, v0, dt );

         var temp = u0; u0 = u; u = temp;

         var temp = v0; v0 = v; v = temp;

         diffuse2(u,u0,v,v0, dt);

         project(u, v, u0, v0);

         var temp = u0; u0 = u; u = temp;

         var temp = v0; v0 = v; v = temp;

         advect(1, u, u0, u0, v0, dt);

         advect(2, v, v0, u0, v0, dt);

         project(u, v, u0, v0 );

     }

     var uiCallback = function(d,u,v) {};

     function Field(dens, u, v) {

         // Just exposing the fields here rather than using accessors is a measurable win during display (maybe 5%)

         // but makes the code ugly.

         this.setDensity = function(x, y, d) {

              dens[(x + 1) + (y + 1) * rowSize] = d;

         }

         this.getDensity = function(x, y) {

              return dens[(x + 1) + (y + 1) * rowSize];

         }

         this.setVelocity = function(x, y, xv, yv) {

              u[(x + 1) + (y + 1) * rowSize] = xv;

              v[(x + 1) + (y + 1) * rowSize] = yv;

         }

         this.getXVelocity = function(x, y) {

              return u[(x + 1) + (y + 1) * rowSize];

         }

         this.getYVelocity = function(x, y) {

              return v[(x + 1) + (y + 1) * rowSize];

         }

         this.width = function() { return width; }

         this.height = function() { return height; }

     }

     function queryUI(d, u, v)

     {

         for (var i = 0; i < size; i++)

             u[i] = v[i] = d[i] = 0.0;

         uiCallback(new Field(d, u, v));

     }

     this.update = function () {

         queryUI(dens_prev, u_prev, v_prev);

         vel_step(u, v, u_prev, v_prev, dt);

         dens_step(dens, dens_prev, u, v, dt);

         displayFunc(new Field(dens, u, v));

     }

     this.setDisplayFunction = function(func) {

         displayFunc = func;

     }

     this.iterations = function() { return iterations; }

     this.setIterations = function(iters) {

         if (iters > 0 && iters <= 100)

            iterations = iters;

     }

     this.setUICallback = function(callback) {

         uiCallback = callback;

     }

     var iterations = 10;

     var visc = 0.5;

     var dt = 0.1;

     var dens;

     var dens_prev;

     var u;

     var u_prev;

     var v;

     var v_prev;

     var width;

     var height;

     var rowSize;

     var size;

     var displayFunc;

     function reset()

     {

         rowSize = width + 2;

         size = (width+2)*(height+2);

         dens = new Array(size);

         dens_prev = new Array(size);

         u = new Array(size);

         u_prev = new Array(size);

         v = new Array(size);

         v_prev = new Array(size);

         for (var i = 0; i < size; i++)

             dens_prev[i] = u_prev[i] = v_prev[i] = dens[i] = u[i] = v[i] = 0;

     }

     this.reset = reset;

     this.setResolution = function (hRes, wRes)

     {

         var res = wRes * hRes;

         if (res > 0 && res < 1000000 && (wRes != width || hRes != height)) {

             width = wRes;

             height = hRes;

             reset();

             return true;

         }

         return false;

     }

     this.setResolution(64, 64);

 }