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  * Get a pointer to the color data.
  69  */
  70 INLINE_MAYBE
  71 const scal_t* color_data(const color_t* c)
  72 {
  73     return &c->r;
  74 }
  75
  76
  77 /*
  78  * Print the color to stdout.
  79  */
  80 INLINE_MAYBE
  81 void color_print(color_t c)
  82 {
  83 #if (SCALAR_SIZE == 8)
  84     const char* fmt = "[ %9.5lf %9.5lf %9.5lf %9.5lf ]";
  85 #else
  86     const char* fmt = "[ %9.5f %9.5f %9.5f %9.5f ]";
  87 #endif
  88     printf(fmt, c.r, c.g, c.b, c.a);
  89 }
  90
  91
  92 /*
  93  * Add two colors together.
  94  */
  95 INLINE_MAYBE
  96 color_t color_add(color_t c1, color_t c2)
  97 {
  98     return color_new(c1.r + c2.r, c1.g + c2.g, c1.b + c2.b, c1.a);
  99 }
 100
 101 /*
 102  * Add three colors together.
 103  */
 104 INLINE_MAYBE
 105 color_t color_add2(color_t c1, color_t c2, color_t c3)
 106 {
 107     return color_add(color_add(c1, c2), c3);
 108 }
 109
 110 /*
 111  * Multiply two colors together.
 112  */
 113 INLINE_MAYBE
 114 color_t color_mult(color_t c1, color_t c2)
 115 {
 116     c1.r *= c2.r;
 117     c1.g *= c2.g;
 118     c1.b *= c2.b;
 119     return c1;
 120 }
 121
 122 /*
 123  * Scale a color by some scalar coefficient.
 124  */
 125 INLINE_MAYBE
 126 color_t color_scale(color_t c, scal_t k)
 127 {
 128     c.r *= k;
 129     c.g *= k;
 130     c.b *= k;
 131     return c;
 132 }
 133
 134 /*
 135  * Scale a color by another color and some scalar coefficient.
 136  */
 137 INLINE_MAYBE
 138 color_t color_scale2(color_t c1, color_t c2, scal_t k)
 139 {
 140     return color_scale(color_mult(c1, c2), k);
 141 }
 142
 143 INLINE_MAYBE
 144 color_t color_blend(color_t d, color_t s)
 145 {
 146     d.r = (S(1.0) - s.a) * d.r + s.a * s.r;
 147     d.g = (S(1.0) - s.a) * d.g + s.a * s.g;
 148     d.b = (S(1.0) - s.a) * d.b + s.a * s.b;
 149     return d;
 150 }
 151
 152 /*
 153  * Clamp a color's channels to the normal range of 0.0 to 1.0.
 154  */
 155 INLINE_MAYBE
 156 color_t color_clamp(color_t c)
 157 {
 158     c.r = scal_clamp(c.r, S(0.0), S(1.0));
 159     c.g = scal_clamp(c.g, S(0.0), S(1.0));
 160     c.b = scal_clamp(c.b, S(0.0), S(1.0));
 161     c.a = scal_clamp(c.a, S(0.0), S(1.0));
 162     return c;
 163 }
 164
 165
 166 /*
 167  * Interpolate smoothly between two colors with an alpha value.
 168  */
 169 INLINE_MAYBE
 170 color_t color_interp(color_t c1, color_t c2, scal_t a)
 171 {
 172     return color_new(c1.r * (S(1.0) - a) + c2.r * a,
 173                      c1.g * (S(1.0) - a) + c2.g * a,
 174                      c1.b * (S(1.0) - a) + c2.b * a, c1.a);
 175 }
 176
 177 /*
 178  * Interpolate smoothly between three colors with barycentric coordinates.
 179  */
 180 INLINE_MAYBE
 181 color_t color_interp2(color_t c1, color_t c2, color_t c3, scal_t b[3])
 182 {
 183     return color_new(c1.r * b[0] + c2.r * b[1] + c3.r * b[2],
 184                      c1.g * b[0] + c2.g * b[1] + c3.g * b[2],
 185                      c1.b * b[0] + c2.b * b[1] + c3.b * b[2], c1.a);
 186 }
 187
 188
 189 /*
 190  * Define integer types for a 32-bit RGBA color representation.
 191  */
 192 typedef uint8_t     rgbachan_t;
 193 typedef uint32_t    rgba_t;
 194
 195 /*
 196  * Split a color into 8-bit RGBA channels.
 197  */
 198 INLINE_MAYBE
 199 void color_split(color_t c, rgbachan_t* r, rgbachan_t* g, rgbachan_t* b, rgbachan_t* a)
 200 {
 201     if (r) *r = (rgbachan_t)(c.r * S(255.0));
 202     if (g) *g = (rgbachan_t)(c.g * S(255.0));
 203     if (b) *b = (rgbachan_t)(c.b * S(255.0));
 204     if (a) *a = (rgbachan_t)(c.a * S(255.0));
 205 }
 206
 207 /*
 208  * Create a new color from a 32-bit RGBA value.
 209  */
 210 INLINE_MAYBE
 211 color_t color_from_rgba(rgba_t n)
 212 {
 213     union {
 214         rgba_t rgba;
 215         struct {
 216             rgbachan_t r, g, b, a;
 217         } chan;
 218     } u;
 219     u.rgba = n;
 220     colorchan_t r = (colorchan_t)u.chan.r / S(255.0);
 221     colorchan_t g = (colorchan_t)u.chan.g / S(255.0);
 222     colorchan_t b = (colorchan_t)u.chan.b / S(255.0);
 223     colorchan_t a = (colorchan_t)u.chan.a / S(255.0);
 224     return color_new(r, g, b, a);
 225 }
 226
 227 /*
 228  * Convert a color to a 32-bit RGBA value.
 229  */
 230 INLINE_MAYBE
 231 rgba_t rgba_from_color(color_t c)
 232 {
 233     union {
 234         rgba_t rgba;
 235         struct {
 236             rgbachan_t r, g, b, a;
 237         } chan;
 238     } u;
 239     color_split(c, &u.chan.r, &u.chan.g, &u.chan.b, &u.chan.a);
 240     return u.rgba;
 241 }
 242
 243
 244 #endif // _COLOR_H_
 245