PBRT
/home/felix/UBC/projects/AdaptiveLightfieldSampling/pbrt_v2/src/3rdparty/openexr-1.7.0/ImfChromaticities.h
00001 
00002 //
00003 // Copyright (c) 2003, Industrial Light & Magic, a division of Lucas
00004 // Digital Ltd. LLC
00005 // 
00006 // All rights reserved.
00007 // 
00008 // Redistribution and use in source and binary forms, with or without
00009 // modification, are permitted provided that the following conditions are
00010 // met:
00011 // *       Redistributions of source code must retain the above copyright
00012 // notice, this list of conditions and the following disclaimer.
00013 // *       Redistributions in binary form must reproduce the above
00014 // copyright notice, this list of conditions and the following disclaimer
00015 // in the documentation and/or other materials provided with the
00016 // distribution.
00017 // *       Neither the name of Industrial Light & Magic nor the names of
00018 // its contributors may be used to endorse or promote products derived
00019 // from this software without specific prior written permission. 
00020 // 
00021 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00022 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00023 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00024 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
00025 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00026 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00027 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00028 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00029 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00030 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00031 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00032 //
00034 
00035 
00036 #ifndef INCLUDED_IMF_CHROMATICITIES_H
00037 #define INCLUDED_IMF_CHROMATICITIES_H
00038 
00039 //-----------------------------------------------------------------------------
00040 //
00041 //      CIE (x,y) chromaticities, and conversions between
00042 //      RGB tiples and CIE XYZ tristimulus values.
00043 //
00044 //-----------------------------------------------------------------------------
00045 
00046 #include "ImathVec.h"
00047 #include "ImathMatrix.h"
00048 
00049 namespace Imf {
00050 
00051    
00052 struct Chromaticities
00053 {
00054     //-----------------------------------------------
00055     // The CIE x and y coordinates of the RGB triples
00056     // (1,0,0), (0,1,0), (0,0,1) and (1,1,1).
00057     //-----------------------------------------------
00058 
00059     Imath::V2f  red;
00060     Imath::V2f  green;
00061     Imath::V2f  blue;
00062     Imath::V2f  white;
00063 
00064     //--------------------------------------------
00065     // Default constructor produces chromaticities
00066     // according to Rec. ITU-R BT.709-3
00067     //--------------------------------------------
00068 
00069     Chromaticities (const Imath::V2f &red   = Imath::V2f (0.6400f, 0.3300f),
00070                     const Imath::V2f &green = Imath::V2f (0.3000f, 0.6000f),
00071                     const Imath::V2f &blue  = Imath::V2f (0.1500f, 0.0600f),
00072                     const Imath::V2f &white = Imath::V2f (0.3127f, 0.3290f));
00073 };
00074 
00075 
00076 //
00077 // Conversions between RGB and CIE XYZ
00078 //
00079 // RGB to XYZ:
00080 //
00081 //      Given a set of chromaticities, c, and the luminance, Y, of the RGB
00082 //      triple (1,1,1), or "white", RGBtoXYZ(c,Y) computes a matrix, M, so
00083 //      that multiplying an RGB value, v, with M produces an equivalent
00084 //      XYZ value, w.  (w == v * M)
00085 // 
00086 //      If we define that
00087 // 
00088 //         (Xr, Yr, Zr) == (1, 0, 0) * M
00089 //         (Xg, Yg, Zg) == (0, 1, 0) * M
00090 //         (Xb, Yb, Zb) == (0, 0, 1) * M
00091 //         (Xw, Yw, Zw) == (1, 1, 1) * M,
00092 // 
00093 //      then the following statements are true:
00094 // 
00095 //         Xr / (Xr + Yr + Zr) == c.red.x
00096 //         Yr / (Xr + Yr + Zr) == c.red.y
00097 // 
00098 //         Xg / (Xg + Yg + Zg) == c.red.x
00099 //         Yg / (Xg + Yg + Zg) == c.red.y
00100 // 
00101 //         Xb / (Xb + Yb + Zb) == c.red.x
00102 //         Yb / (Xb + Yb + Zb) == c.red.y
00103 // 
00104 //         Xw / (Xw + Yw + Zw) == c.red.x
00105 //         Yw / (Xw + Yw + Zw) == c.red.y
00106 // 
00107 //         Yw == Y.
00108 // 
00109 // XYZ to RGB:
00110 // 
00111 //      YYZtoRGB(c,Y) returns RGBtoXYZ(c,Y).inverse().
00112 // 
00113 
00114 Imath::M44f     RGBtoXYZ (const Chromaticities chroma, float Y);
00115 Imath::M44f     XYZtoRGB (const Chromaticities chroma, float Y);
00116 
00117 
00118 } // namespace Imf
00119 
00120 #endif