cos2000v2/lib/2d.c

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#include "types.h"
#include "vga.h"
#include "video.h"
#include "2d.h"
#include "math.h"
/******************************************************************************/
/* Affiche une ligne entre les points sp<73>cifi<66>s */
void line(u32 x1, u32 y1, u32 x2, u32 y2, u8 color)
{
s32 dx, dy, sdx, sdy;
u32 i, dxabs, dyabs, x, y, px, py;
dx = x2 - x1; /* distance horizontale de la line */
dy = y2 - y1; /* distance verticale de la line * */
dxabs = abs(dx);
dyabs = abs(dy);
sdx = sgn(dx);
sdy = sgn(dy);
x = dyabs >> 1;
y = dxabs >> 1;
px = x1;
py = y1;
writepxl(px, py, color);
if (dxabs >= dyabs) { /* la ligne est plus horizontale que verticale */
for (i = 0; i < dxabs; i++) {
y += dyabs;
if (y >= dxabs) {
y -= dxabs;
py += sdy;
}
px += sdx;
writepxl(px, py, color);
}
} else { /* la ligne est plus verticale que horizontale */
for (i = 0; i < dyabs; i++) {
x += dxabs;
if (x >= dyabs) {
x -= dyabs;
px += sdx;
}
py += sdy;
writepxl(px, py, color);
}
}
}