plan9fox/sys/src/9/bitsy/gamma.c
2011-03-30 19:35:09 +03:00

51 lines
646 B
C

#include <u.h>
#include <libc.h>
#include <stdio.h>
double gamma = 1.6;
int
remap5(int i)
{
double v;
v = (double)i/31.0;
return 31.0*pow(v, gamma);
}
int
remap6(int i)
{
double v;
v = (double)i/63.0;
return 63.0*pow(v, gamma);
}
int
remap(int i)
{
int r, g, b;
b = i & 0x1F;
g = (i>>5) & 0x3F;
r = (i>>11) & 0x1F;
return (remap5(r)<<11) | (remap6(g)<<5) | (remap5(b)<<0);
}
void
main(void)
{
int i;
printf("/* gamma = %.2f */\n", gamma);
printf("ushort gamma[65536] = {\n");
for(i=0; i<65536; i++){
if((i%8) == 0)
printf("\t");
printf("0x%.4x, ", remap(i));
if((i%8) == 7)
printf("\n");
}
printf("};\n");
}