107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
/**************************************************************************
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*
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* Copyright 2010 VMware, Inc.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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**************************************************************************/
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/**
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* @file
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* SRGB translation.
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*
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* @author Brian Paul <brianp@vmware.com>
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* @author Michal Krol <michal@vmware.com>
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* @author Jose Fonseca <jfonseca@vmware.com>
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*/
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#ifndef U_FORMAT_SRGB_H_
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#define U_FORMAT_SRGB_H_
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#include "pipe/p_compiler.h"
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#include "u_math.h"
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extern const float
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util_format_srgb_8unorm_to_linear_float_table[256];
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extern const uint8_t
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util_format_srgb_to_linear_8unorm_table[256];
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extern const uint8_t
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util_format_linear_to_srgb_8unorm_table[256];
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/**
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* Convert a unclamped linear float to srgb value in the [0,255].
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* XXX this hasn't been tested (render to srgb surface).
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* XXX this needs optimization.
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*/
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static INLINE uint8_t
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util_format_linear_float_to_srgb_8unorm(float x)
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{
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if (x >= 1.0f)
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return 255;
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else if (x >= 0.0031308f)
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return float_to_ubyte(1.055f * powf(x, 0.41666f) - 0.055f);
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else if (x > 0.0f)
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return float_to_ubyte(12.92f * x);
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else
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return 0;
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}
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/**
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* Convert an 8-bit sRGB value from non-linear space to a
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* linear RGB value in [0, 1].
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* Implemented with a 256-entry lookup table.
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*/
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static INLINE float
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util_format_srgb_8unorm_to_linear_float(uint8_t x)
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{
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return util_format_srgb_8unorm_to_linear_float_table[x];
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}
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/**
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* Convert a 8bit normalized value from linear to srgb.
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*/
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static INLINE uint8_t
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util_format_linear_to_srgb_8unorm(uint8_t x)
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{
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return util_format_linear_to_srgb_8unorm_table[x];
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}
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/**
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* Convert a 8bit normalized value from srgb to linear.
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*/
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static INLINE uint8_t
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util_format_srgb_to_linear_8unorm(uint8_t x)
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{
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return util_format_srgb_to_linear_8unorm_table[x];
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}
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#endif /* U_FORMAT_SRGB_H_ */
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