forked from KolibriOS/kolibrios
39 lines
669 B
C
39 lines
669 B
C
|
#include <math.h> //sqrt
|
||
|
|
|
||
|
|
static float csa[8][2]; /* antialias */
|
||
|
|
|
||
|
|
void alias_init()
|
||
|
|
{
|
||
|
|
float Ci[8] =
|
||
|
|
{
|
||
|
|
-0.6f, -0.535f, -0.33f, -0.185f, -0.095f, -0.041f, -0.0142f, -0.0037f
|
||
|
|
};
|
||
|
|
|
||
|
|
int i;
|
||
|
|
|
||
|
|
for (i = 0; i < 8; i++)
|
||
|
|
{
|
||
|
|
csa[i][0] = (float) (1.0 / sqrt(1.0 + Ci[i] * Ci[i]));
|
||
|
|
csa[i][1] = (float) (Ci[i] / sqrt(1.0 + Ci[i] * Ci[i]));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void antialias(float x[], int n)
|
||
|
|
{
|
||
|
|
int i, k;
|
||
|
|
float a, b;
|
||
|
|
|
||
|
|
for (k = 0; k < n; k++)
|
||
|
|
{
|
||
|
|
for (i = 0; i < 8; i++)
|
||
|
|
{
|
||
|
|
a = x[17 - i];
|
||
|
|
b = x[18 + i];
|
||
|
|
x[17 - i] = a * csa[i][0] - b * csa[i][1];
|
||
|
|
x[18 + i] = b * csa[i][0] + a * csa[i][1];
|
||
|
|
}
|
||
|
|
x += 18;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|