1/************************************************************************** 2 * 3 * Copyright 2010 VMware, Inc. 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 17 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 18 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 19 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 20 * USE OR OTHER DEALINGS IN THE SOFTWARE. 21 * 22 * The above copyright notice and this permission notice (including the 23 * next paragraph) shall be included in all copies or substantial portions 24 * of the Software. 25 * 26 **************************************************************************/ 27 28/** 29 * @file 30 * SRGB translation. 31 * 32 * @author Brian Paul <brianp@vmware.com> 33 * @author Michal Krol <michal@vmware.com> 34 * @author Jose Fonseca <jfonseca@vmware.com> 35 */ 36 37#ifndef U_FORMAT_SRGB_H_ 38#define U_FORMAT_SRGB_H_ 39 40 41#include "pipe/p_compiler.h" 42#include "u_math.h" 43 44 45extern const float 46util_format_srgb_8unorm_to_linear_float_table[256]; 47 48extern const uint8_t 49util_format_srgb_to_linear_8unorm_table[256]; 50 51extern const uint8_t 52util_format_linear_to_srgb_8unorm_table[256]; 53 54 55/** 56 * Convert a unclamped linear float to srgb value in the [0,255]. 57 * XXX this hasn't been tested (render to srgb surface). 58 * XXX this needs optimization. 59 */ 60static INLINE uint8_t 61util_format_linear_float_to_srgb_8unorm(float x) 62{ 63 if (x >= 1.0f) 64 return 255; 65 else if (x >= 0.0031308f) 66 return float_to_ubyte(1.055f * powf(x, 0.41666f) - 0.055f); 67 else if (x > 0.0f) 68 return float_to_ubyte(12.92f * x); 69 else 70 return 0; 71} 72 73 74/** 75 * Convert an 8-bit sRGB value from non-linear space to a 76 * linear RGB value in [0, 1]. 77 * Implemented with a 256-entry lookup table. 78 */ 79static INLINE float 80util_format_srgb_8unorm_to_linear_float(uint8_t x) 81{ 82 return util_format_srgb_8unorm_to_linear_float_table[x]; 83} 84 85 86/** 87 * Convert a 8bit normalized value from linear to srgb. 88 */ 89static INLINE uint8_t 90util_format_linear_to_srgb_8unorm(uint8_t x) 91{ 92 return util_format_linear_to_srgb_8unorm_table[x]; 93} 94 95 96/** 97 * Convert a 8bit normalized value from srgb to linear. 98 */ 99static INLINE uint8_t 100util_format_srgb_to_linear_8unorm(uint8_t x) 101{ 102 return util_format_srgb_to_linear_8unorm_table[x]; 103} 104 105 106#endif /* U_FORMAT_SRGB_H_ */ 107