Dogcows Code - chaz/rasterize/blob - color.h

   1
   2 /*
   3  * CS5600 University of Utah
   4  * Charles McGarvey
   5  * mcgarvey@eng.utah.edu
   6  */
   7
   8 #ifndef _COLOR_H_
   9 #define _COLOR_H_
  10
  11 #include "common.h"
  12
  13
  14 /*
  15  * A color channel will be the same as a scalar.
  16  */
  17 typedef scal_t colorchan_t;
  18
  19 /*
  20  * A color class.
  21  * Colors are represented by RGBA values between 0.0 and 1.0.
  22  */
  23 struct color
  24 {
  25     colorchan_t r;
  26     colorchan_t g;
  27     colorchan_t b;
  28     colorchan_t a;
  29 };
  30 typedef struct color color_t;
  31
  32 /*
  33  * Initialize a color.
  34  */
  35 INLINE_MAYBE
  36 void color_init(color_t* c, colorchan_t r, colorchan_t g, colorchan_t b, colorchan_t a)
  37 {
  38     c->r = r;
  39     c->g = g;
  40     c->b = b;
  41     c->a = a;
  42 }
  43
  44
  45 /*
  46  * Create a new color, copied by value.
  47  */
  48 INLINE_MAYBE
  49 color_t color_new(colorchan_t r, colorchan_t g, colorchan_t b, colorchan_t a)
  50 {
  51     color_t c;
  52     color_init(&c, r, g, b, a);
  53     return c;
  54 }
  55
  56 #define COLOR_CLEAR   color_new(S(0.0), S(0.0), S(0.0), S(0.0))
  57 #define COLOR_BLACK   color_new(S(0.0), S(0.0), S(0.0), S(1.0))
  58 #define COLOR_RED     color_new(S(1.0), S(0.0), S(0.0), S(1.0))
  59 #define COLOR_GREEN   color_new(S(0.0), S(1.0), S(0.0), S(1.0))
  60 #define COLOR_BLUE    color_new(S(0.0), S(0.0), S(1.0), S(1.0))
  61 #define COLOR_YELLOW  color_new(S(1.0), S(1.0), S(0.0), S(1.0))
  62 #define COLOR_MAGENTA color_new(S(1.0), S(0.0), S(1.0), S(1.0))
  63 #define COLOR_CYAN    color_new(S(0.0), S(1.0), S(1.0), S(1.0))
  64 #define COLOR_WHITE   color_new(S(1.0), S(1.0), S(1.0), S(1.0))
  65
  66
  67 /*
  68  * Print the color to stdout.
  69  */
  70 INLINE_MAYBE
  71 void color_print(color_t c)
  72 {
  73 #if (SCALAR_SIZE == 8)
  74     const char* fmt = "[ %9.5lf %9.5lf %9.5lf %9.5lf ]";
  75 #else
  76     const char* fmt = "[ %9.5f %9.5f %9.5f %9.5f ]";
  77 #endif
  78     printf(fmt, c.r, c.g, c.b, c.a);
  79 }
  80
  81
  82 /*
  83  * Add two colors together.  Color may need to be clamped afterward.
  84  */
  85 INLINE_MAYBE
  86 color_t color_add(color_t c1, color_t c2)
  87 {
  88     return color_new(c1.r + c2.r, c1.g + c2.g, c1.b + c2.b, c1.a + c2.a);
  89 }
  90
  91 /*
  92  * Add three colors together.  Color may need to be clamped afterward.
  93  */
  94 INLINE_MAYBE
  95 color_t color_add2(color_t c1, color_t c2, color_t c3)
  96 {
  97     return color_add(color_add(c1, c2), c3);
  98 }
  99
 100 /*
 101  * Clamp a color's channels to the normal range of 0.0 to 1.0.
 102  */
 103 INLINE_MAYBE
 104 color_t color_clamp(color_t c)
 105 {
 106     c.r = scal_clamp(c.r, S(0.0), S(1.0));
 107     c.g = scal_clamp(c.g, S(0.0), S(1.0));
 108     c.b = scal_clamp(c.b, S(0.0), S(1.0));
 109     c.a = scal_clamp(c.a, S(0.0), S(1.0));
 110     return c;
 111 }
 112
 113
 114 /*
 115  * Interpolate smoothly between two colors with an alpha value.
 116  */
 117 INLINE_MAYBE
 118 color_t color_interp(color_t c1, color_t c2, scal_t a)
 119 {
 120     return color_new(c1.r * (S(1.0) - a) + c2.r * a,
 121                      c1.g * (S(1.0) - a) + c2.g * a,
 122                      c1.b * (S(1.0) - a) + c2.b * a,
 123                      c1.a * (S(1.0) - a) + c2.a * a);
 124 }
 125
 126 /*
 127  * Interpolate smoothly between three colors with barycentric coordinates.
 128  */
 129 INLINE_MAYBE
 130 color_t color_interp2(color_t c1, color_t c2, color_t c3, scal_t b[3])
 131 {
 132     return color_new(c1.r * b[0] + c2.r * b[1] + c3.r * b[2],
 133                      c1.g * b[0] + c2.g * b[1] + c3.g * b[2],
 134                      c1.b * b[0] + c2.b * b[1] + c3.b * b[2],
 135                      S(1.0));
 136 }
 137
 138
 139 /*
 140  * Define integer types for a 32-bit RGBA color representation.
 141  */
 142 typedef uint8_t     rgbachan_t;
 143 typedef uint32_t    rgba_t;
 144
 145 /*
 146  * Create a new color from a 32-bit RGBA value.
 147  */
 148 INLINE_MAYBE
 149 color_t color_from_rgba(rgba_t n)
 150 {
 151     colorchan_t r = (colorchan_t)UNPACK(n, 3) / S(255.0);
 152     colorchan_t g = (colorchan_t)UNPACK(n, 2) / S(255.0);
 153     colorchan_t b = (colorchan_t)UNPACK(n, 1) / S(255.0);
 154     colorchan_t a = (colorchan_t)UNPACK(n, 0) / S(255.0);
 155     return color_new(r, g, b, a);
 156 }
 157
 158 /*
 159  * Split a color into 8-bit RGBA channels.
 160  */
 161 INLINE_MAYBE
 162 void color_split(color_t c, rgbachan_t* r, rgbachan_t* g, rgbachan_t* b, rgbachan_t* a)
 163 {
 164     if (r) *r = (rgbachan_t)(c.r * S(255.0));
 165     if (g) *g = (rgbachan_t)(c.g * S(255.0));
 166     if (b) *b = (rgbachan_t)(c.b * S(255.0));
 167     if (a) *a = (rgbachan_t)(c.a * S(255.0));
 168 }
 169
 170 /*
 171  * Convert a color to a 32-bit RGBA value.
 172  */
 173 INLINE_MAYBE
 174 rgba_t rgba_from_color(color_t c)
 175 {
 176     rgbachan_t r, g, b, a;
 177     color_split(c, &r, &g, &b, &a);
 178     return ((rgba_t)r << 24) | ((rgba_t)g << 16) | ((rgba_t)b << 8) | (rgba_t)a;
 179 }
 180
 181
 182 #endif // _COLOR_H_
 183