Paul Berry d4c80f5f85 glsl: improve the accuracy of the asin() builtin function. ... The previous formula for asin(x) was algebraically equivalent to: sign(x)*(pi/2 - sqrt(1-|x|)*(A + B|x| + C|x|^2)) where A, B, and C were arbitrary constants determined by a curve fit. This formula had a worst case absolute error of 0.00448, an unbounded worst case relative error, and a discontinuity near x=0. Changed the formula to: sign(x)*(pi/2 - sqrt(1-|x|)*(pi/2 + (pi/4-1)|x| + A|x|^2 + B|x|^3)) where A and B are arbitrary constants determined by a curve fit. This has a worst case absolute error of 0.00039, a worst case relative error of 0.000405, and no discontinuities. I don't expect a significant performance degradation, since the extra multiply-accumulate should be fast compared to the sqrt() computation. Fixes piglit tests {vs,fs}-asin-float and {vs,fs}-atan-*		2011-08-01 14:37:38 -07:00
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ir	glsl: improve the accuracy of the asin() builtin function.	2011-08-01 14:37:38 -07:00
profiles	glsl: Add compiler support for ARB_shader_texture_lod.	2011-05-09 11:23:54 -07:00
tools	glsl/generate_builtins.py: Remove regexp to kill pointer addresses.	2011-06-14 18:29:48 -07:00