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color.h
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color.h
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// color.h -- Color datatype
//
// Copyright (C) 2005-2008, 2010-2012 Miles Bader <miles@gnu.org>
//
// This source code is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 3, or (at
// your option) any later version. See the file COPYING for more details.
//
// Written by Miles Bader <miles@gnu.org>
//
#ifndef SNOGRAY_COLOR_H
#define SNOGRAY_COLOR_H
#include "snogmath.h"
#include "tuple-adaptor.h"
namespace snogray {
// Light intensity.
//
typedef float intens_t;
// A color.
//
// Abstract color type. This is mostly an opaque type, and as many
// standard math operators work on colors directly (usually treating each
// component independently), a Color can usually be treated like the
// traditional C numeric types.
//
class Color
{
public:
// Type of one color component.
//
typedef intens_t component_t;
// Number of color components stored.
//
static const unsigned NUM_COMPONENTS = 3; // RGB
// Default constructor.
//
// Note that by default, the color-components are _not initialized_!
// This make code generation in much more efficient some cases (where
// color temporaries are declared and then later assigned to, the
// compiler isn't always smart enough to get rid of the initialization of
// the temporary).
//
// In general Colors should be treated like traditional C scalar types,
// and can just be initialized with zero where desired.
//
Color () {}
// RGB constructor. This constructor is Deprecated: It is only used
// in some test-scene and image-loading code, and should be replaced by
// some more proper color-space conversion.
//
Color (component_t r, component_t g, component_t b);
// Scalar constructors; these are very handy for mixing colors and
// scalars in expressions.
//
Color (int grey)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] = grey;
}
Color (unsigned grey)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] = grey;
}
Color (float grey)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] = grey;
}
Color (double grey)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] = grey;
}
const Color &operator+= (const Color &col2)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] += col2[c];
return *this;
}
void operator-= (const Color &col2)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] -= col2[c];
}
void operator*= (const Color &filter)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] *= filter[c];
}
void operator/= (const Color &filter)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
if (filter[c] != 0)
_components[c] /= filter[c];
}
// Explicit handling of scaling (results in better code generation
// than relying on implicit promotion of the scale argument to Color).
// We enumerate all common scalar types to try and avoid overload
// ambiguity.
void operator*= (float scale)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] *= scale;
}
void operator*= (double scale)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] *= component_t (scale);
}
void operator*= (int scale)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] *= scale;
}
void operator*= (unsigned scale)
{
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
_components[c] *= scale;
}
// Doesn't make much sense physically, of course, but useful for some
// formulas.
//
Color operator- () const
{
Color rval;
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
rval[c] = -_components[c];
return rval;
}
// Division by a scalar.
//
Color operator/ (float denom) const;
Color operator/ (double denom) const;
Color operator/ (int denom) const;
Color operator/ (unsigned denom) const;
void operator/= (float denom) { *this *= 1 / component_t (denom); }
void operator/= (double denom) { *this *= 1 / component_t (denom); }
void operator/= (int denom) { *this *= 1 / component_t (denom); }
void operator/= (unsigned denom) { *this *= 1 / component_t (denom); }
intens_t intensity () const
{
component_t sum = _components[0];
for (unsigned c = 1; c < NUM_COMPONENTS; c++)
sum += _components[c];
return sum / NUM_COMPONENTS;
}
Color clamp (intens_t max_intens) const
{
Color rval;
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
rval[c] = min (_components[c], max_intens);
return rval;
}
Color clamp (float min_intens, float max_intens) const
{
Color rval;
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
rval[c] = min (max (_components[c], min_intens), max_intens);
return rval;
}
Color pow (component_t exp) const
{
Color rval;
for (unsigned c = 0; c < NUM_COMPONENTS; c++)
rval[c] = std::pow (_components[c], exp);
return rval;
}
component_t min_component () const
{
component_t min_comp = _components[0];
for (unsigned c = 1; c < NUM_COMPONENTS; c++)
min_comp = min (_components[c], min_comp);
return min_comp;
}
component_t max_component () const
{
component_t max_comp = _components[0];
for (unsigned c = 1; c < NUM_COMPONENTS; c++)
max_comp = max (_components[c], max_comp);
return max_comp;
}
// Array access to color components.
//
component_t &operator[] (unsigned c) { return _components[c]; }
const component_t &operator[] (unsigned c) const { return _components[c]; }
// Getter and setter methods for RGB primaries. These methods are
// deprecated: They are only used by some image I/O code, and should be
// replaced by some more proper color-space conversion.
//
component_t r () const;
component_t g () const;
component_t b () const;
//
void set_rgb (component_t r, component_t g, component_t b);
private:
// Array components.
//
component_t _components[NUM_COMPONENTS];
};
inline bool operator== (const Color &col1, const Color &col2)
{
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
if (col1[c] != col2[c])
return false;
return true;
}
inline bool operator!= (const Color &col1, const Color &col2)
{
return ! operator== (col1, col2);
}
inline bool operator> (const Color &col1, const Color &col2)
{
Color::component_t sum1 = col1[0], sum2 = col2[0];
for (unsigned c = 1; c < Color::NUM_COMPONENTS; c++)
{
sum1 += col1[c];
sum2 += col2[c];
}
return sum1 > sum2;
}
inline bool operator<= (const Color &col1, const Color &col2)
{
return ! operator> (col1, col2);
}
inline bool operator< (const Color &col1, const Color &col2)
{
Color::component_t sum1 = col1[0], sum2 = col2[0];
for (unsigned c = 1; c < Color::NUM_COMPONENTS; c++)
{
sum1 += col1[c];
sum2 += col2[c];
}
return sum1 < sum2;
}
inline bool operator>= (const Color &col1, const Color &col2)
{
return ! operator< (col1, col2);
}
inline Color operator+ (const Color &col1, const Color &col2)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col1[c] + col2[c];
return rval;
}
inline Color operator- (const Color &col1, const Color &col2)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col1[c] - col2[c];
return rval;
}
inline Color operator* (const Color &col1, const Color &filter)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col1[c] * filter[c];
return rval;
}
inline Color operator/ (const Color &col1, const Color &filter)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = (filter[c] == 0) ? 0 : col1[c] / filter[c];
return rval;
}
// Multiplication by scalars is very common (for scaling operations), so
// provide explicit overloads for it, which helps the compiler. We
// enumerate all common scalar types to try and avoid overload ambiguity.
//
inline Color operator* (const Color &col, float scale)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * scale;
return rval;
}
inline Color operator* (float scale, const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * scale;
return rval;
}
inline Color operator* (const Color &col, double scale)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * Color::component_t (scale);
return rval;
}
inline Color operator* (double scale, const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * Color::component_t (scale);
return rval;
}
inline Color operator* (const Color &col, int scale)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * scale;
return rval;
}
inline Color operator* (int scale, const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = col[c] * scale;
return rval;
}
// Similarly for division by a scalar.
//
inline Color
Color::operator/ (float denom) const
{
return *this * (1 / component_t (denom));
}
inline Color
Color::operator/ (double denom) const
{
return *this * (1 / component_t (denom));
}
inline Color
Color::operator/ (int denom) const
{
return *this * (1 / component_t (denom));
}
inline Color
Color::operator/ (unsigned denom) const
{
return *this * (1 / component_t (denom));
}
inline Color pow (const Color &base, const Color &exp)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = pow (base[c], exp[c]);
return rval;
}
inline Color log (const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = log (col[c]);
return rval;
}
inline Color fmod (const Color &col1, const Color &col2)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = fmod (col1[c], col2[c]);
return rval;
}
inline Color abs (const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = abs (col[c]);
return rval;
}
inline Color sqrt (const Color &col)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = sqrt (col[c]);
return rval;
}
inline Color max (const Color &col1, const Color &col2)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = max (col1[c], col2[c]);
return rval;
}
inline Color min (const Color &col1, const Color &col2)
{
Color rval;
for (unsigned c = 0; c < Color::NUM_COMPONENTS; c++)
rval[c] = min (col1[c], col2[c]);
return rval;
}
// An adaptor for converting Colors to/from tuples of type DT*.
//
template<typename DT>
class TupleAdaptor<Color, DT>
{
public:
static const unsigned TUPLE_LEN = 3;
TupleAdaptor (DT *_tuple) : tuple (_tuple) { }
operator Color () const
{
float r = tuple[0], g = tuple[1], b = tuple[2];
return Color (r, g, b);
}
TupleAdaptor &operator= (const Color &col)
{
for (unsigned c = 0; c < TUPLE_LEN; c++)
tuple[c] = col[c];
return *this;
}
private:
DT *tuple;
};
}
#endif /* SNOGRAY_COLOR_H */
// arch-tag: 389b3ebb-55a4-4d70-afbe-91bdb72d28ed