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Kaleidoscope uses nearest neighbor instead of linear interpolation (performance boost)

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This commit is contained in:
ippo615 2014-02-08 12:46:46 -05:00
parent 0b36fb91a9
commit 02acf9b2ba
1 changed files with 14 additions and 88 deletions
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102
src/filters/Kaleidoscope.js
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@ -48,53 +48,13 @@
sin = Math.sin(theta*conversion);
cos = Math.cos(theta*conversion);
for( radius=0; radius<rSize; radius+=1 ){
x = xMid+rMax*radius/rSize*cos;
y = yMid+rMax*radius/rSize*sin;
if( x <= 1 ){ x = 1; }
if( x >= xSize-0.5 ){ x = xSize-1; }
if( y <= 1 ){ y = 1; }
if( y >= ySize-0.5 ){ y = ySize-1; }
// Interpolate x and y by going +-0.5 around the pixel's central point
// this gives us the 4 nearest pixels to our 1x1 non-aligned pixel.
// We average the vaules of those pixels based on how much of our
// non-aligned pixel overlaps each of them.
x1 = x - 0.5;
x2 = x + 0.5;
x1i = Math.floor(x1);
x2i = Math.floor(x2);
y1 = y - 0.5;
y2 = y + 0.5;
y1i = Math.floor(y1);
y2i = Math.floor(y2);
scale = (1-(x1-x1i))*(1-(y1-y1i));
i = (y1i*xSize + x1i)*4;
r = srcPixels[i+0]*scale;
g = srcPixels[i+1]*scale;
b = srcPixels[i+2]*scale;
a = srcPixels[i+3]*scale;
scale = (1-(x1-x1i))*(y2-y2i);
i = (y2i*xSize + x1i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
scale = (x2-x2i)*(y2-y2i);
i = (y2i*xSize + x2i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
scale = (x2-x2i)*(1-(y1-y1i));
i = (y1i*xSize + x2i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
x = Math.floor(xMid+rMax*radius/rSize*cos);
y = Math.floor(yMid+rMax*radius/rSize*sin);
i = (y*xSize + x)*4;
r = srcPixels[i+0];
g = srcPixels[i+1];
b = srcPixels[i+2];
a = srcPixels[i+3];
// Store it
//i = (theta * xSize + radius) * 4;
@ -163,47 +123,13 @@
radius = Math.sqrt(dx*dx + dy*dy)*rSize/rMax;
theta = (Math.atan2(dy,dx)*180/Math.PI + 360 + phaseShift)%360;
theta = theta*tSize/360;
// Interpolate x and y by going +-0.5 around the pixel's central point
// this gives us the 4 nearest pixels to our 1x1 non-aligned pixel.
// We average the vaules of those pixels based on how much of our
// non-aligned pixel overlaps each of them.
x1 = theta - 0.5;
x2 = theta + 0.5;
x1i = Math.floor(x1);
x2i = Math.floor(x2);
y1 = radius - 0.5;
y2 = radius + 0.5;
y1i = Math.floor(y1);
y2i = Math.floor(y2);
scale = (1-(x1-x1i))*(1-(y1-y1i));
i = (y1i*xSize + x1i)*4;
r = srcPixels[i+0]*scale;
g = srcPixels[i+1]*scale;
b = srcPixels[i+2]*scale;
a = srcPixels[i+3]*scale;
scale = (1-(x1-x1i))*(y2-y2i);
i = (y2i*xSize + x1i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
scale = (x2-x2i)*(y2-y2i);
i = (y2i*xSize + x2i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
scale = (x2-x2i)*(1-(y1-y1i));
i = (y1i*xSize + x2i)*4;
r += srcPixels[i+0]*scale;
g += srcPixels[i+1]*scale;
b += srcPixels[i+2]*scale;
a += srcPixels[i+3]*scale;
x1 = Math.floor(theta);
y1 = Math.floor(radius);
i = (y1*xSize + x1)*4;
r = srcPixels[i+0];
g = srcPixels[i+1];
b = srcPixels[i+2];
a = srcPixels[i+3];
// Store it
i = (y*xSize + x)*4;