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author | marha <marha@users.sourceforge.net> | 2013-08-19 09:07:37 +0200 |
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committer | marha <marha@users.sourceforge.net> | 2013-08-19 09:07:37 +0200 |
commit | 2d042f719910c5aa1ba9f4a47b21009c729c345e (patch) | |
tree | 2b20d89d5f1ca342ca6f1d817c18b324adf7086f /mesalib/src/gallium/auxiliary/util/u_format_srgb.h | |
parent | c3d3ea464f7f4e53e8fe3e11ecada36cb209ba4d (diff) | |
parent | 854ec4da20ddff9b830be0a7d5b81d8cb4774132 (diff) | |
download | vcxsrv-2d042f719910c5aa1ba9f4a47b21009c729c345e.tar.gz vcxsrv-2d042f719910c5aa1ba9f4a47b21009c729c345e.tar.bz2 vcxsrv-2d042f719910c5aa1ba9f4a47b21009c729c345e.zip |
Merge remote-tracking branch 'origin/released'
* origin/released:
fontconfig libX11 libXdmcp libxcb xkeyboard-config mesa pixman xserver git update 19 aug 2013
Conflicts:
fontconfig/src/fccache.c
Diffstat (limited to 'mesalib/src/gallium/auxiliary/util/u_format_srgb.h')
-rw-r--r-- | mesalib/src/gallium/auxiliary/util/u_format_srgb.h | 56 |
1 files changed, 46 insertions, 10 deletions
diff --git a/mesalib/src/gallium/auxiliary/util/u_format_srgb.h b/mesalib/src/gallium/auxiliary/util/u_format_srgb.h index 82ed9575d..740a91974 100644 --- a/mesalib/src/gallium/auxiliary/util/u_format_srgb.h +++ b/mesalib/src/gallium/auxiliary/util/u_format_srgb.h @@ -39,6 +39,7 @@ #include "pipe/p_compiler.h" +#include "u_pack_color.h" #include "u_math.h" @@ -51,23 +52,58 @@ util_format_srgb_to_linear_8unorm_table[256]; extern const uint8_t util_format_linear_to_srgb_8unorm_table[256]; +extern const unsigned +util_format_linear_to_srgb_helper_table[104]; + /** * Convert a unclamped linear float to srgb value in the [0,255]. - * XXX this hasn't been tested (render to srgb surface). - * XXX this needs optimization. */ static INLINE uint8_t util_format_linear_float_to_srgb_8unorm(float x) { - if (x >= 1.0f) - return 255; - else if (x >= 0.0031308f) - return float_to_ubyte(1.055f * powf(x, 0.41666f) - 0.055f); - else if (x > 0.0f) - return float_to_ubyte(12.92f * x); - else - return 0; + /* this would be exact but (probably much) slower */ + if (0) { + if (x >= 1.0f) + return 255; + else if (x >= 0.0031308f) + return float_to_ubyte(1.055f * powf(x, 0.41666666f) - 0.055f); + else if (x > 0.0f) + return float_to_ubyte(12.92f * x); + else + return 0; + } + else { + /* + * This is taken from https://gist.github.com/rygorous/2203834 + * Use LUT and do linear interpolation. + */ + union fi almostone, minval, f; + unsigned tab, bias, scale, t; + + almostone.ui = 0x3f7fffff; + minval.ui = (127-13) << 23; + + /* + * Clamp to [2^(-13), 1-eps]; these two values map to 0 and 1, respectively. + * The tests are carefully written so that NaNs map to 0, same as in the + * reference implementation. + */ + if (!(x > minval.f)) + x = minval.f; + if (x > almostone.f) + x = almostone.f; + + /* Do the table lookup and unpack bias, scale */ + f.f = x; + tab = util_format_linear_to_srgb_helper_table[(f.ui - minval.ui) >> 20]; + bias = (tab >> 16) << 9; + scale = tab & 0xffff; + + /* Grab next-highest mantissa bits and perform linear interpolation */ + t = (f.ui >> 12) & 0xff; + return (uint8_t) ((bias + scale*t) >> 16); + } } |