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#include "mandel.h"
#define MAX(x, y) (x > y ? x : y)
#define MIN(x, y) (x < y ? x : y)
static Color color_hsl_to_rgb(ColorHSL color_hsl);
unsigned int color_texture_new(int count)
{
ColorHSL hsl;
Color *palette;
unsigned int texture;
palette = malloc(sizeof(Color) * count);
if (palette == NULL)
return 0;
for (int i = 0; i < count; i++)
{
hsl.h = (uint8_t)(255.0 * ((double)i / (double)count));
hsl.s = 150;
hsl.l = 127;
palette[i] = color_hsl_to_rgb(hsl);
}
for (int i = 0, j = count - 1; i < j; i++, j--)
{
Color tmp = palette[i];
palette[i] = palette[j];
palette[j] = tmp;
}
GL_CALL(glGenTextures(1, &texture));
GL_CALL(glBindTexture(GL_TEXTURE_1D, texture));
GL_CALL(glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST));
GL_CALL(glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST));
GL_CALL(glTexImage1D(GL_TEXTURE_1D, 0, GL_RGB, count + 1, 0, GL_RGB, GL_UNSIGNED_BYTE, palette));
free(palette);
return texture;
}
static Color color_hsl_to_rgb(ColorHSL color_hsl)
{
Color color_rgb;
double h;
double s;
double l;
double r;
double g;
double b;
double temp1, temp2, tempr, tempg, tempb;
h = color_hsl.h / 256.0;
s = color_hsl.s / 256.0;
l = color_hsl.l / 256.0;
if(s == 0)
{
r = l;
g = l;
b = l;
}
else
{
if (l < 0.5) temp2 = l * (1 + s);
else temp2 = (l + s) - (l * s);
temp1 = 2 * l - temp2;
tempr = h + 1.0 / 3.0;
if (tempr > 1) tempr--;
tempg = h;
tempb = h - 1.0 / 3.0;
if (tempb < 0) tempb++;
if (tempr < 1.0 / 6.0) r = temp1 + (temp2 - temp1) * 6.0 * tempr;
else if (tempr < 0.5) r = temp2;
else if (tempr < 2.0 / 3.0) r = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempr) * 6.0;
else r = temp1;
if (tempg < 1.0 / 6.0) g = temp1 + (temp2 - temp1) * 6.0 * tempg;
else if (tempg < 0.5) g = temp2;
else if (tempg < 2.0 / 3.0) g = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempg) * 6.0;
else g = temp1;
if(tempb < 1.0 / 6.0) b = temp1 + (temp2 - temp1) * 6.0 * tempb;
else if(tempb < 0.5) b = temp2;
else if(tempb < 2.0 / 3.0) b = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempb) * 6.0;
else b = temp1;
}
color_rgb.r = (int)(r * 256.0);
color_rgb.g = (int)(g * 256.0);
color_rgb.b = (int)(b * 256.0);
return (color_rgb);
}
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