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POOpenGL ES glReadPixels returns wrong values
 

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    <p>First of all first time here so hello everyone. After searching the net for days including this site I failed to overcome this problem:</p> <pre><code>public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glMatrixMode(GL10.GL_MODELVIEW); gl.glLoadIdentity(); //load identity GLU.gluLookAt(gl, 0, -5, -25, 0, 0, 0, 0, 2, 0); //set camera if (fingerInput.isClicking()){ /* Color Picking 4 START */ gl.glDisable(GL10.GL_TEXTURE_2D); //turn off texturing, lighting and fog gl.glDisable(GL10.GL_FOG); gl.glDisable(GL10.GL_LIGHTING); while (i&lt;squares.size()){ //draw picking colors squares.get(i).pickingDraw(gl); //note: picking is the same as draw() only with id colors and not textures i++; } i=0; gl.glReadPixels(fingerInput.getStart().x, screen_height-fingerInput.getStart().y, 1, 1, GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, pixels); //read what was the color id pressed, store it in 'pixels' (a 4 slots array buffer) Log.d("tlog","at coords: ("+(screen_height-fingerInput.getStart().x)+", "+(screen_height-fingerInput.getStart().y)+")"); for (j=0; j&lt;4; j++){ RGBA[j] = (int)(pixels.get(j) &amp; 0xff); if (RGBA[j] &lt; 0) RGBA[j]+=256; //correcting error caused by java using unsigned bytes and opengl singed bytes } </code></pre> <p>anyway, for picking purposes, the squares are drawn each with a unique color,(currently drawing 3 squares with colors 99,96 and 93 red, and 0s at blue green alpha) glReadPixels returns on clicking either (99,0,0) or (91,0,0).</p> <p>if the box is colored (x,0,0,255) it returns a value as if it had a list of possible values with spaces of 8 between them. (91,99,107..) sort of "rounding" each read color value to nearest "possible" value.</p>
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