/*
 * CS5600 University of Utah
 * Charles McGarvey
 * mcgarvey@eng.utah.edu
 */

#ifndef __COLOR_H__
#define __COLOR_H__

#include "common.h"


/*
 * A color channel will be the same as a scalar.
 */
typedef scal_t colorchan_t;

/*
 * A color class.
 * Colors are represented by RGBA values between 0.0 and 1.0.
 */
struct color
{
    colorchan_t r;
    colorchan_t g;
    colorchan_t b;
    colorchan_t a;
};
typedef struct color color_t;

/*
 * Initialize a color.
 */
__fast__
void color_init(color_t* c, colorchan_t r, colorchan_t g, colorchan_t b, colorchan_t a)
{
    c->r = r;
    c->g = g;
    c->b = b;
    c->a = a;
}


/*
 * Create a new color, copied by value.
 */
__fast__
color_t color_new(colorchan_t r, colorchan_t g, colorchan_t b, colorchan_t a)
{
    color_t c;
    color_init(&c, r, g, b, a);
    return c;
}

#define COLOR_CLEAR   color_new(S(0.0), S(0.0), S(0.0), S(0.0))
#define COLOR_BLACK   color_new(S(0.0), S(0.0), S(0.0), S(1.0))
#define COLOR_RED     color_new(S(1.0), S(0.0), S(0.0), S(1.0))
#define COLOR_GREEN   color_new(S(0.0), S(1.0), S(0.0), S(1.0))
#define COLOR_BLUE    color_new(S(0.0), S(0.0), S(1.0), S(1.0))
#define COLOR_YELLOW  color_new(S(1.0), S(1.0), S(0.0), S(1.0))
#define COLOR_MAGENTA color_new(S(1.0), S(0.0), S(1.0), S(1.0))
#define COLOR_CYAN    color_new(S(0.0), S(1.0), S(1.0), S(1.0))
#define COLOR_WHITE   color_new(S(1.0), S(1.0), S(1.0), S(1.0))


/*
 * Define integer types for a 32-bit RGBA color representation.
 */
typedef uint32_t    rgba_t;
typedef uint8_t     rgbachan_t;

/*
 * Create a new color from a 32-bit RGBA value.
 */
__fast__
color_t color_from_rgba(rgba_t n)
{
    colorchan_t r = (colorchan_t)UNPACK(n, 3) / S(255.0);
    colorchan_t g = (colorchan_t)UNPACK(n, 2) / S(255.0);
    colorchan_t b = (colorchan_t)UNPACK(n, 1) / S(255.0);
    colorchan_t a = (colorchan_t)UNPACK(n, 0) / S(255.0);
    return color_new(r, g, b, a);
}

/*
 * Split a color into 8-bit RGBA channels.
 */
__fast__
void color_split(color_t c, rgbachan_t* r, rgbachan_t* g, rgbachan_t* b, rgbachan_t* a)
{
    if (r) *r = (rgbachan_t)(c.r * S(255.0));
    if (g) *g = (rgbachan_t)(c.g * S(255.0));
    if (b) *b = (rgbachan_t)(c.b * S(255.0));
    if (a) *a = (rgbachan_t)(c.a * S(255.0));
}

/*
 * Convert a color to a 32-bit RGBA value.
 */
__fast__
rgba_t rgba_from_color(color_t c)
{
    rgbachan_t r, g, b, a;
    color_split(c, &r, &g, &b, &a);
    return ((rgba_t)r << 24) | ((rgba_t)g << 16) | ((rgba_t)b << 8) | (rgba_t)a;
}


#endif // __COLOR_H__