/*
 * 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.
 */
INLINE_MAYBE
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.
 */
INLINE_MAYBE
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))


/*
 * Print the color to stdout.
 */
INLINE_MAYBE
void color_print(color_t c)
{
#if (SCALAR_SIZE == 8)
    const char* fmt = "[ %9.5lf %9.5lf %9.5lf %9.5lf ]";
#else
    const char* fmt = "[ %9.5f %9.5f %9.5f %9.5f ]";
#endif
    printf(fmt, c.r, c.g, c.b, c.a);
}


/*
 * Add two colors together.
 */
INLINE_MAYBE
color_t color_add(color_t c1, color_t c2)
{
    return color_new(c1.r + c2.r, c1.g + c2.g, c1.b + c2.b, c1.a);
}

/*
 * Add three colors together.
 */
INLINE_MAYBE
color_t color_add2(color_t c1, color_t c2, color_t c3)
{
    return color_add(color_add(c1, c2), c3);
}

/*
 * Multiply two colors together.
 */
INLINE_MAYBE
color_t color_mult(color_t c1, color_t c2)
{
    c1.r *= c2.r;
    c1.g *= c2.g;
    c1.b *= c2.b;
    return c1;
}

/*
 * Scale a color by some scalar coefficient.
 */
INLINE_MAYBE
color_t color_scale(color_t c, scal_t k)
{
    c.r *= k;
    c.g *= k;
    c.b *= k;
    return c;
}

/*
 * Scale a color by another color and some scalar coefficient.
 */
INLINE_MAYBE
color_t color_scale2(color_t c1, color_t c2, scal_t k)
{
    return color_scale(color_mult(c1, c2), k);
}

INLINE_MAYBE
color_t color_blend(color_t d, color_t s)
{
    d.r = (S(1.0) - s.a) * d.r + s.a * s.r;
    d.g = (S(1.0) - s.a) * d.g + s.a * s.g;
    d.b = (S(1.0) - s.a) * d.b + s.a * s.b;
    return d;
}

/*
 * Clamp a color's channels to the normal range of 0.0 to 1.0.
 */
INLINE_MAYBE
color_t color_clamp(color_t c)
{
    c.r = scal_clamp(c.r, S(0.0), S(1.0));
    c.g = scal_clamp(c.g, S(0.0), S(1.0));
    c.b = scal_clamp(c.b, S(0.0), S(1.0));
    c.a = scal_clamp(c.a, S(0.0), S(1.0));
    return c;
}


/*
 * Interpolate smoothly between two colors with an alpha value.
 */
INLINE_MAYBE
color_t color_interp(color_t c1, color_t c2, scal_t a)
{
    return color_new(c1.r * (S(1.0) - a) + c2.r * a,
                     c1.g * (S(1.0) - a) + c2.g * a,
                     c1.b * (S(1.0) - a) + c2.b * a, c1.a);
}

/*
 * Interpolate smoothly between three colors with barycentric coordinates.
 */
INLINE_MAYBE
color_t color_interp2(color_t c1, color_t c2, color_t c3, scal_t b[3])
{
    return color_new(c1.r * b[0] + c2.r * b[1] + c3.r * b[2],
                     c1.g * b[0] + c2.g * b[1] + c3.g * b[2],
                     c1.b * b[0] + c2.b * b[1] + c3.b * b[2], c1.a);
}


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

/*
 * Create a new color from a 32-bit RGBA value.
 */
INLINE_MAYBE
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.
 */
INLINE_MAYBE
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.
 */
INLINE_MAYBE
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_