docs: private void renderDot( int cx , int cy , float Z , int rgb ) {
  		for (int i = -dotRadius; i <= dotRadius; i++) {
  			int y = cy+i;
  			if( y < 0 || y >= imageRgb.height )
  				continue;
  			for (int j = -dotRadius; j <= dotRadius; j++) {
  				int x = cx+j;
  				if( x < 0 || x >= imageRgb.width )
  					continue;
  
  				int pixelIndex = imageDepth.getIndex(x,y);
  				float depth = imageDepth.data[pixelIndex];
  				if( depth > Z ) {
  					imageDepth.data[pixelIndex] = Z;
  					imageRgb.data[pixelIndex] = rgb;
  				}
  			}
  		}
  	}