-extern int fbwidth, fbheight, fbbpp;
-extern unsigned char *fbpixels;
+#include "inttypes.h"
+
+extern int fb_width, fb_height, fb_bpp;
+extern uint16_t *fb_pixels; /* system-RAM pixel buffer: use swap_buffers(fb_pixels) */
+/* video memory pointers. might both point to the front buffer if there is not
+ * enough memory for page flipping. use swap_buffers(0) to flip. */
+extern uint16_t *vmem_back, *vmem_front;
+