static int SVGA_FlipHWSurface(_THIS, SDL_Surface *surface)
{
vga_setdisplaystart(flip_offset[flip_page]);
flip_page=!flip_page;
surface->pixels=flip_address[flip_page];
vga_waitretrace();
return(0);
}
void demo1(void)
{
int x, y;
int targetx, targety;
int pageoffset[3] =
{
0,
320 * 240 / 4,
2 * 320 * 240 / 4
};
int writepage;
int count, startclock;
/* Window coordinate initially at center. */
x = VWIDTH / 2 - WINWIDTH / 2;
y = VHEIGHT / 2 - WINHEIGHT / 2;
targetx = x;
targety = y;
/* Page flipping initialization. */
vga_setdisplaystart(0); /* Display page 0, write to page 1. */
writepage = 1;
count = 0;
startclock = clock();
for (;;) {
/* Copy window to screen. */
vga_copytoplanar256(vbuf + y * WIDTH + x, WIDTH,
pageoffset[writepage], 80, WINWIDTH, WINHEIGHT);
/* Flip pages. */
vga_setdisplaystart(pageoffset[writepage] * 4);
#ifndef TRIPLEBUFFERING
/* Conventional double-buffering (page-flipping). */
vga_waitretrace();
writepage ^= 1;
#else
/* Triple buffering; no need to wait for vertical retrace. */
writepage = (writepage + 1) % 3;
#endif
if (x == targetx && y == targety) {
/* Create new target. */
targetx = rand() % (VWIDTH - WINWIDTH);
targety = rand() % (VHEIGHT - WINHEIGHT);
}
/* Move towards target. */
if (x < targetx)
x++;
if (x > targetx)
x--;
if (y < targety)
y++;
if (y > targety)
y--;
/* Boundary checks. */
if (x < 0)
x = 0;
if (x > VWIDTH - WINWIDTH)
x = VWIDTH - WINWIDTH;
if (y < 0)
y = 0;
if (y > VHEIGHT - WINHEIGHT)
y = VHEIGHT - WINHEIGHT;
if (vga_getkey())
break;
count++;
}
printf("Method 1: frame rate %ld\n", count * CLOCKS_PER_SEC
/ (clock() - startclock));
}
void demo2(void)
{
int x, y;
int targetx, targety;
int vwidth, vheight;
int count, startclock;
/* Make sure window fits in video memory. */
vwidth = VWIDTH;
if (vwidth > 640)
vwidth = 640;
vheight = VHEIGHT;
if (vheight > 400)
vheight = 400;
vga_setlogicalwidth(vwidth);
/* Copy virtual screen to logical screen in video memory. */
vga_copytoplanar256(vbuf, VWIDTH, 0, vwidth / 4,
vwidth, VHEIGHT);
/* Window coordinates initially at center. */
x = vwidth / 2 - WINWIDTH / 2;
y = vheight / 2 - WINHEIGHT / 2;
targetx = x;
targety = y;
count = 0;
startclock = clock();
for (;;) {
/* Set video memory window. */
vga_setdisplaystart((y * vwidth / 4) * 4 + x);
vga_waitretrace();
if (x == targetx && y == targety) {
/* Create new target. */
targetx = rand() % (vwidth - WINWIDTH);
targety = rand() % (vheight - WINHEIGHT);
}
/* Move towards target. */
if (x < targetx)
x++;
if (x > targetx)
x--;
if (y < targety)
y++;
if (y > targety)
y--;
/* Boundary checks. */
if (x < 0)
x = 0;
if (x > vwidth - WINWIDTH)
x = vwidth - WINWIDTH;
if (y < 0)
y = 0;
if (y > vheight - WINHEIGHT)
y = vheight - WINHEIGHT;
if (vga_getkey())
break;
count++;
}
printf("Method 2: frame rate %ld\n", count*CLOCKS_PER_SEC
/(clock() - startclock));
}
