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/*
* Mesa 3-D graphics library
*
* Copyright (C) 2011 VMware, Inc. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* Types, macros, etc for the GLchan datatype.
* The swrast module is kind of hard-coded for 8bpp color channels but
* may be recompiled to use 16- or 32-bit color channels. But that
* feature is seldom used and is likely broken in various ways.
*/
#ifndef U_CHAN_H
#define U_CHAN_H
#include "main/config.h"
/**
* Default bits per color channel: 8, 16 or 32
*/
#ifndef CHAN_BITS
#define CHAN_BITS 8
#endif
/**
* Color channel data type.
*/
#if CHAN_BITS == 8
typedef GLubyte GLchan;
#define CHAN_MAX 255
#define CHAN_MAXF 255.0F
#define CHAN_TYPE GL_UNSIGNED_BYTE
#elif CHAN_BITS == 16
typedef GLushort GLchan;
#define CHAN_MAX 65535
#define CHAN_MAXF 65535.0F
#define CHAN_TYPE GL_UNSIGNED_SHORT
#elif CHAN_BITS == 32
typedef GLfloat GLchan;
#define CHAN_MAX 1.0
#define CHAN_MAXF 1.0F
#define CHAN_TYPE GL_FLOAT
#else
#error "illegal number of color channel bits"
#endif
#if CHAN_BITS == 8
#define CHAN_TO_UBYTE(c) (c)
#define CHAN_TO_USHORT(c) (((c) << 8) | (c))
#define CHAN_TO_SHORT(c) (((c) << 7) | ((c) >> 1))
#define CHAN_TO_FLOAT(c) UBYTE_TO_FLOAT(c)
#define CLAMPED_FLOAT_TO_CHAN(c, f) CLAMPED_FLOAT_TO_UBYTE(c, f)
#define UNCLAMPED_FLOAT_TO_CHAN(c, f) UNCLAMPED_FLOAT_TO_UBYTE(c, f)
#define COPY_CHAN4(DST, SRC) COPY_4UBV(DST, SRC)
#elif CHAN_BITS == 16
#define CHAN_TO_UBYTE(c) ((c) >> 8)
#define CHAN_TO_USHORT(c) (c)
#define CHAN_TO_SHORT(c) ((c) >> 1)
#define CHAN_TO_FLOAT(c) ((GLfloat) ((c) * (1.0 / CHAN_MAXF)))
#define CLAMPED_FLOAT_TO_CHAN(c, f) CLAMPED_FLOAT_TO_USHORT(c, f)
#define UNCLAMPED_FLOAT_TO_CHAN(c, f) UNCLAMPED_FLOAT_TO_USHORT(c, f)
#define COPY_CHAN4(DST, SRC) COPY_4V(DST, SRC)
#elif CHAN_BITS == 32
#define CHAN_TO_UBYTE(c) FLOAT_TO_UBYTE(c)
#define CHAN_TO_USHORT(c) ((GLushort) (CLAMP((c), 0.0f, 1.0f) * 65535.0))
#define CHAN_TO_SHORT(c) ((GLshort) (CLAMP((c), 0.0f, 1.0f) * 32767.0))
#define CHAN_TO_FLOAT(c) (c)
#define CLAMPED_FLOAT_TO_CHAN(c, f) c = (f)
#define UNCLAMPED_FLOAT_TO_CHAN(c, f) c = (f)
#define COPY_CHAN4(DST, SRC) COPY_4V(DST, SRC)
#else
#error unexpected CHAN_BITS size
#endif
/**
* Convert 4 floats to GLchan values.
* \param dst pointer to destination GLchan[4] array.
* \param f pointer to source GLfloat[4] array.
*/
#define UNCLAMPED_FLOAT_TO_RGBA_CHAN(dst, f) \
do { \
UNCLAMPED_FLOAT_TO_CHAN((dst)[0], (f)[0]); \
UNCLAMPED_FLOAT_TO_CHAN((dst)[1], (f)[1]); \
UNCLAMPED_FLOAT_TO_CHAN((dst)[2], (f)[2]); \
UNCLAMPED_FLOAT_TO_CHAN((dst)[3], (f)[3]); \
} while (0)
#endif /* U_CHAN_H */
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