alexr4_Processing-VariousRnD/_ARCHIVES/ImageFiltering/DepthTest/FastBlurPixels.pde

void fastblur(int[] pix, int w, int h, int radius)
{
  if (radius<1) {
    return;
  }
  int wm=w-1;
  int hm=h-1;
  int wh=w*h;
  int div=radius+radius+1;
  int r[]=new int[wh];
  int g[]=new int[wh];
  int b[]=new int[wh];
  int rsum, gsum, bsum, x, y, i, p, p1, p2, yp, yi, yw;
  int vmin[] = new int[max(w, h)];
  int vmax[] = new int[max(w, h)];
  int dv[]=new int[256*div];
  for (i=0; i<256*div; i++) {
    dv[i]=(i/div);
  }

  yw=yi=0;

  for (y=0; y<h; y++) {
    rsum=gsum=bsum=0;
    for (i=-radius; i<=radius; i++) {
      p=pix[yi+min(wm, max(i, 0))];
      rsum+=(p & 0xff0000)>>16;
      gsum+=(p & 0x00ff00)>>8;
      bsum+= p & 0x0000ff;
    }
    for (x=0; x<w; x++) {

      r[yi]=dv[rsum];
      g[yi]=dv[gsum];
      b[yi]=dv[bsum];

      if (y==0) {
        vmin[x]=min(x+radius+1, wm);
        vmax[x]=max(x-radius, 0);
      }
      p1=pix[yw+vmin[x]];
      p2=pix[yw+vmax[x]];

      rsum+=((p1 & 0xff0000)-(p2 & 0xff0000))>>16;
      gsum+=((p1 & 0x00ff00)-(p2 & 0x00ff00))>>8;
      bsum+= (p1 & 0x0000ff)-(p2 & 0x0000ff);
      yi++;
    }
    yw+=w;
  }

  for (x=0; x<w; x++) {
    rsum=gsum=bsum=0;
    yp=-radius*w;
    for (i=-radius; i<=radius; i++) {
      yi=max(0, yp)+x;
      rsum+=r[yi];
      gsum+=g[yi];
      bsum+=b[yi];
      yp+=w;
    }
    yi=x;
    for (y=0; y<h; y++) {
      pix[yi]=0xff000000 | (dv[rsum]<<16) | (dv[gsum]<<8) | dv[bsum];
      if (x==0) {
        vmin[y]=min(y+radius+1, hm)*w;
        vmax[y]=max(y-radius, 0)*w;
      }
      p1=x+vmin[y];
      p2=x+vmax[y];

      rsum+=r[p1]-r[p2];
      gsum+=g[p1]-g[p2];
      bsum+=b[p1]-b[p2];

      yi+=w;
    }
  }
}
