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# include/cinder/ChanTraits.h

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    00001 /*
    00002  Copyright (c) 2010, The Barbarian Group
    00003  All rights reserved.
    00004
    00005  Redistribution and use in source and binary forms, with or without modification, are permitted provided that
    00006  the following conditions are met:
    00007
    00008     * Redistributions of source code must retain the above copyright notice, this list of conditions and
    00009     the following disclaimer.
    00010     * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
    00011     the following disclaimer in the documentation and/or other materials provided with the distribution.
    00012
    00013  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
    00014  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    00015  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
    00016  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    00017  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    00018  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    00019  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    00020  POSSIBILITY OF SUCH DAMAGE.
    00021 */
    00022
    00023 #pragma once
    00024
    00025 #include "cinder/Cinder.h"
    00026
    00027 #include <boost/preprocessor/seq.hpp>
    00028
    00029 namespace cinder {
    00030
    00031 template<typename T>
    00032 struct CHANTRAIT
    00033 {
    00034 };
    00035
    00036 template<>
    00037 struct CHANTRAIT<uint8_t>
    00038 {
    00039     typedef uint32_t Sum;
    00040     typedef uint32_t Accum;
    00041     typedef int32_t SignedSum;
    00042     static uint8_t max() { return 255; }
    00043     static uint8_t convert( uint8_t v ) { return v; }
    00044     static uint8_t convert( uint16_t v ) { return v / 257; }
    00045     static uint8_t convert( float v ) { return static_cast<uint8_t>( v * 255 ); }
    00046     static uint8_t grayscale( uint8_t r, uint8_t g, uint8_t b ) { return ( r * 74 + g * 147 + b * 35 ) >> 8; }
    00048     static uint8_t premultiply( uint8_t c, uint8_t a ) { return c * 255 / a; } // TODO: need Jim Blinn's optimized trick here
    00049 };
    00050
    00051 template<>
    00052 struct CHANTRAIT<uint16_t>
    00053 {
    00054     typedef uint32_t Sum;
    00055     typedef uint32_t Accum;
    00056     typedef int32_t SignedSum;
    00057     static uint16_t max() { return 65535; }
    00058     static uint16_t convert( uint8_t v ) { return ( v << 8 ) | v; }
    00059     static uint16_t convert( uint16_t v ) { return v; }
    00060     static uint16_t convert( float v ) { return static_cast<uint16_t>( v * 65535 ); }
    00061     static uint16_t grayscale( uint16_t r, uint16_t g, uint16_t b ) { return ( r * 9511 + g * 18674 + b * 4582 ) >> 15; }
    00062 };
    00063
    00064 template<>
    00065 struct CHANTRAIT<float>
    00066 {
    00067     typedef float Sum;
    00068     typedef float Accum;
    00069     typedef float SignedSum;
    00070     static float max() { return 1.0f; }
    00071     static float convert( uint8_t v ) { return v / 255.0f; }
    00072     static float convert( uint16_t v ) { return v / 65535.0f; }
    00073     static float convert( float v ) { return v; }
    00074     static float grayscale( float r, float g, float b ) { return r * 0.212f + g * 0.701f + b * 0.087f; }
    00076     static float premultiply( float c, float a ) { return c * a; }
    00077 };
    00078
    00079 #define CHANNEL_TYPES (uint8_t)(float)
    00080
    00081 } // namespace cinder