glReadPixels problem

Discussion in 'iOS Programming' started by mlady, Oct 2, 2008.

  1. mlady macrumors member

    Joined:
    Sep 18, 2008
    #1
    Hi,

    I want to use something like this:
    Code:
    	GLvoid* pixelColor[4];
    	glReadPixels(x, y, 1, 1, GL_RGBA, GL_FLOAT, &pixelColor);
    	NSLog(@"%f %f %f",pixelColor[0],pixelColor[1],pixelColor[2]);
    
    And this is inside my render function.

    No matter if I clear the background or whatever is on background it's giving me same (disordered) values.

    I wanted to use glReadBuffer(), but it seems Xcode does not know this method. How many buffers are in iPhone?

    basically I want to use this in my 2d racing game to determine, if still inside the track.

    Anyone can help?
    Thanks
     
  2. mlady thread starter macrumors member

    Joined:
    Sep 18, 2008
    #2
    just got it working!
    Should be:
    Code:
    	Byte pixelColor[4];
    
    	glReadPixels(x,y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixelColor[0]);
    	
    	NSLog(@"%d %d %d",pixelColor[0],pixelColor[1],pixelColor[2]);
    
    
     

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