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polar coordinate distortion (Read 608 times)
James Carruthers
polar coordinate distortion
Feb 7th, 2010, 3:24am  
Hi all,


I have been racking my brains about this but I just cannot seem to make any workable code!

I have two PImage's - source and destination - and I want to transform the source in to the blank destination. Although I could hard code it - I'd rather the function adjusts to the height and width.

I think it should be something like this - but I know I am missing something quite important!

Code:

  for (int i = 0; i < des.pixels.length; i++) {
    float x = i%des.width;
    float y = floor(i/des.width);
    float r = sqrt(pow(x,2)+pow(y,2));
    float a = atan2(y,x);
    int x2 = int(r*cos(radians(a))+src.width/2.0);
    int y2 = int(r*sin(radians(a))+src.height/2.0);
    if ( y2*src.width*x2 < src.pixels.length && y2*src.width*x2 > 0) {
    des.pixels[int(y)*des.width*int(x)] = src.pixels[y2*src.width*x2];
    }  
}



James
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James Carruthers
Re: polar coordinate distortion
Reply #1 - Feb 7th, 2010, 12:28pm  
Got it Smiley

*edited - just in case anyone notices!*

Code:

PImage src;


void setup() {
  src = loadImage("src.jpg");
  size(720, 720);
  frameRate(60);
}

void draw() {

  background(128);

  //create destination image
  PImage des = createImage(720, 720, RGB);

  des.loadPixels();
  src.loadPixels();

  for (int x = 0; x < des.width; x++) {
    for (int y = 0; y < des.height; y++) {

	float r = sqrt((pow(x-des.width/2,2)+pow(y-des.width/2,2)));
	float a = atan2(y-des.width/2,x-des.width/2);

	int x3 = int(map(a, PI, -PI, 0, src.width));
	int y3 = int(map(r, 0, des.height/2, 0, src.height));

	des.set(x,y,src.get(x3,y3));
    }
  }
  
  des.updatePixels();

  image(des, 0, 0);

}
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