This function draw a square in a framebuffer.
void dg_fb_putsquare(dg_framebuffer_t *fb, sfVector2u position, unsigned int size, sfColor color);
dg_fb_putsquare(fb, pos, 20, sfBlue);
void dg_fb_putsquare(dg_framebuffer_t *fb, sfVector2u position,
unsigned int size, sfColor color)
{
for (int i = position.x; i < position.x + size; i++)
for (int j = position.y; j < position.y + size; j++)
dg_fb_putpx(fb, i, j, color);
}