docs: public void configure( int width , int height , float vfov ) {
  		declareVectors( width, height );
  
  		float r = (float)Math.tan(vfov/2.0f);
  
  		for (int pixelY = 0; pixelY < height; pixelY++) {
  			float z = 2*r*pixelY/(height-1) - r;
  			for (int pixelX = 0; pixelX < width; pixelX++) {
  				float theta = GrlConstants.F_PI2*pixelX/width - GrlConstants.F_PI;
  				float x = (float)Math.cos(theta);
  				float y = (float)Math.sin(theta);
  
  				vectors[pixelY*width+pixelX].set(x,y,z);
  			}
  		}
  	}