# Talk:GL2x

From wiki.gp2x.org

You might find this interesting (-Synkro 11:50, 2 December 2005 (GMT)):

- Fixed Point Arithmetic on the ARM (69Kb .pdf)
- A Fixed-point 3D Graphics Library with Energy-efficient Cache Architecture for Mobile Multimedia Systems (149K .pdf)

Thanks, I'll take a look at them. -Andrew j w 12:12, 2 December 2005 (GMT)

GPU work in fixed point arithmetic, and moreover many values can be clamped to [0,1] or [-1,1] for improved accuracy. For instance, all color values must lie in the [0,1] range, and after applying te modelview transformation all vertices are in "normalized coordinates" which means that they must be in the [-1,1] range (-1 <= x <= 1, -1 = y <= 1, 0 <= z <= 1 in opengl, and -1 <= z <= 1 in direct3d, or the other way around, can't remember)