hyperultra/src/rotrect.c

44 lines
835 B
C

#include "rotrect.h"
#include "cfg.h"
#include "lzy.h"
#include <math.h>
static void
rotate(double *x, double *y, double angle)
{
const double s = sin(angle);
const double c = cos(angle);
const double ox = *x;
const double oy = *y;
*x = ox * c - oy * s;
*y = ox * s + oy * c;
}
void
rotrect(double x, double y, double width, double height, double angle)
{
double xs[4] = {
width / 2.0,
width / 2.0,
-width / 2.0,
-width / 2.0,
};
double ys[4] = {
-height / 2.0,
height / 2.0,
height / 2.0,
-height / 2.0,
};
for (int i = 0; i < 4; i++) {
rotate(&xs[i], &ys[i], angle);
xs[i] = round(xs[i] + x);
ys[i] = round(ys[i] + y);
}
LZY_DrawLine(xs[0], ys[0], xs[1], ys[1]);
LZY_DrawLine(xs[1], ys[1], xs[2], ys[2]);
LZY_DrawLine(xs[2], ys[2], xs[3], ys[3]);
LZY_DrawLine(xs[3], ys[3], xs[0], ys[0]);
}