Fastest way to do multiple calculations on a texture

Questions & Answers
1

I’m working on an editor based script to generate prerendered textures, but this question should apply to runtime textures too. I’m currently iterating thru each pixel and doing a chain of operations on a list of floats, then applying them to a texture. Its working, but its slower than I think it should be. I was wondering if there is some way to make it go faster, like using a better datatype or somehow getting the gpu to do some of the work.

Here’s a greatly simplified version of what I’m doing:

void makeTextureForSave(int size){
 texture = new Texture2D(size, size);
 for(x = 0; x< size; x++){
 for(int y = 0; y< size; y++){
 float[] noise = getValue(new Vector3(x, y, 0));
 Color color = new Color(noise[0],noise[1], noise[2]);
 texture.SetPixel(x, y, color);
 }
 }
 texture.Apply();
}
float[] getValue(Vector3 pos){
 //greatly simplified
 return color(getColorInput(),invert(screenBlend(perlinNoise(), voronoiNoise()));
}
float[] color(float[] in1, float[]in2){
 //example
 for(i=0; i<4; i++) output <em>= in1_*in2*;*_</em>

return output;
}
Can this be done faster?

2
  1. Make a shader which does that on graphics card using shader if you can (and do not retrieve the result back to system memory) - that is the fastest way
  2. Try modifying all pixels at once, by doing GetPixels, SetPixels (although I’m not sure that speeds up things a lot)