michael@0: load(libdir + "util.js");
michael@0: 
michael@0: var SobelX = [[-1.0,  0.0,  1.0],
michael@0:               [-2.0,  0.0,  2.0],
michael@0:               [-1.0,  0.0,  1.0]];
michael@0: var SobelY = [[ 1.0,  2.0,  1.0],
michael@0:               [ 0.0,  0.0,  0.0],
michael@0:               [-1.0, -2.0, -1.0]];
michael@0: 
michael@0: function stripedImage(w, h) {
michael@0:   var resultArray = new Array(w * h);
michael@0:   for (var y = 0; y < h; y++) {
michael@0:     for (var x = 0; x < w; x++) {
michael@0:       resultArray[y*w + x] = (Math.abs(x%100-y%100) < 10) ? 32 : 0;
michael@0:     }
michael@0:   }
michael@0:   return resultArray;
michael@0: }
michael@0: 
michael@0: function edgesSequentially(data, width, height) {
michael@0:   var data1 = new Array(width * height);
michael@0:   for (var y = 0; y < height; y++) {
michael@0:     for (var x = 0; x < width; x++) {
michael@0:       var total = compute(x, y);
michael@0:       data1[y*width + x] = total | 0;
michael@0:     }
michael@0:   }
michael@0:   return data1;
michael@0: 
michael@0:   function compute(x, y) {
michael@0:       var totalX = 0;
michael@0:       var totalY = 0;
michael@0: 
michael@0:       var offYMin = (y == 0 ? 0 : -1);
michael@0:       var offYMax = (y == height - 1 ? 0 : 1);
michael@0:       var offXMin = (x == 0 ? 0 : -1);
michael@0:       var offXMax = (x == width - 1 ? 0 : 1);
michael@0: 
michael@0:       for (var offY = offYMin; offY <= offYMax; offY++) {
michael@0:         for (var offX = offXMin; offX <= offXMax; offX++) {
michael@0:           var e = data[(y + offY) * width + x + offX];
michael@0:           totalX += e * SobelX[offY + 1][offX + 1];
michael@0:           totalY += e * SobelY[offY + 1][offX + 1];
michael@0:         }
michael@0:       }
michael@0: 
michael@0:     return (Math.abs(totalX) + Math.abs(totalY))/8.0 | 0;
michael@0:   }
michael@0: }
michael@0: 
michael@0: function edgesParallel(data) {
michael@0:   var pa = new ParallelArray([Height, Width], function (y, x) {
michael@0:     var totalX = 0;
michael@0:     var totalY = 0;
michael@0: 
michael@0:     var offYMin = (y == 0 ? 0 : -1);
michael@0:     var offYMax = (y == Height - 1 ? 0 : 1);
michael@0:     var offXMin = (x == 0 ? 0 : -1);
michael@0:     var offXMax = (x == Width - 1 ? 0 : 1);
michael@0: 
michael@0:     for (var offY = offYMin; offY <= offYMax; offY++) {
michael@0:       for (var offX = offXMin; offX <= offXMax; offX++) {
michael@0:         var e = data.get(y + offY, x + offX);
michael@0:         totalX += e * SobelX[offY + 1][offX + 1];
michael@0:         totalY += e * SobelY[offY + 1][offX + 1];
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return (Math.abs(totalX) + Math.abs(totalY))/8.0 | 0;
michael@0:   });
michael@0:   return pa.flatten();
michael@0: }
michael@0: 
michael@0: var Width = 1024;
michael@0: var Height = 768;
michael@0: var ArrInput = stripedImage(Width, Height);
michael@0: var ParArrInput2D = new ParallelArray([Height, Width],
michael@0:                                       function (y, x) ArrInput[y*Width + x]);
michael@0: 
michael@0: benchmark("EDGES", 2, DEFAULT_MEASURE * 20,
michael@0:           function() edgesSequentially(ArrInput, Width, Height),
michael@0:           function() edgesParallel(ParArrInput2D));