backported fixes from rtxon

[dosdemo] / src / dos / gfx.c

diff --git a/src/dos/gfx.c b/src/dos/gfx.c
index 46cec31..cbb1ed4 100644 (file)
--- a/src/dos/gfx.c
+++ b/src/dos/gfx.c
@@ -1,10 +1,8 @@
-#ifndef GFX_H_
-#define GFX_H_
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>
+#include "gfx.h"
 #include "vbe.h"
 #include "cdpmi.h"
 
@@ -30,12 +28,15 @@ static struct vbe_info *vbe_info;
 static struct vbe_mode_info *mode_info;
 static int pal_bits = 6;
 
+static void *vpgaddr[2];
+
+
 void *set_video_mode(int xsz, int ysz, int bpp)
 {
        int i;
        static uint16_t *modes;
        uint16_t best = 0;
-       unsigned int fbsize;
+       unsigned int fbsize, pgsize;
 
 #ifdef __DJGPP__
        __djgpp_nearptr_enable();
@@ -94,8 +95,20 @@ void *set_video_mode(int xsz, int ysz, int bpp)
        }
        */
 
-       fbsize = xsz * ysz * mode_info->num_img_pages * (bpp / CHAR_BIT);
-       return (void*)dpmi_mmap(mode_info->fb_addr, fbsize);
+       printf("avail video pages: %d\n", mode_info->num_img_pages);
+       printf("bytes per scanline: %d (%d pixels)\n", vbe_get_scanlen(VBE_SCANLEN_BYTES),
+                       vbe_get_scanlen(VBE_SCANLEN_PIXELS));
+
+       pgsize = xsz * ysz * (bpp / CHAR_BIT);
+       fbsize = mode_info->num_img_pages * pgsize;
+       vpgaddr[0] = (void*)dpmi_mmap(mode_info->fb_addr, fbsize);
+
+       if(mode_info->num_img_pages > 1) {
+               vpgaddr[1] = (char*)vpgaddr[0] + pgsize;
+       } else {
+               vpgaddr[1] = 0;
+       }
+       return vpgaddr[0];
 }
 
 int set_text_mode(void)
@@ -154,42 +167,32 @@ void set_palette(int idx, int r, int g, int b)
        vbe_set_palette(idx, col, 1, pal_bits);
 }
 
-#ifdef __WATCOMC__
-void wait_vsync_asm(void);
-#pragma aux wait_vsync_asm = \
-       "mov dx, 0x3da" \
-       "l1:" \
-       "in al, dx" \
-       "and al, 0x8" \
-       "jnz l1" \
-       "l2:" \
-       "in al, dx" \
-       "and al, 0x8" \
-       "jz l2" \
-       modify[al dx];
-
-void wait_vsync(void)
+void *page_flip(int vsync)
 {
-       wait_vsync_asm();
-}
-#endif
+       static int frame;
+       void *nextaddr;
+       int y, when, bufidx;
 
-#ifdef __DJGPP__
-void wait_vsync(void)
-{
-       asm volatile (
-               "mov $0x3da, %%dx\n\t"
-               "0:\n\t"
-               "in %%dx, %%al\n\t"
-               "and $8, %%al\n\t"
-               "jnz 0b\n\t"
-               "0:\n\t"
-               "in %%dx, %%al\n\t"
-               "and $8, %%al\n\t"
-               "jz 0b\n\t"
-               :::"%eax","%edx");
+       if(!vpgaddr[1]) {
+               /* page flipping not supported */
+               return 0;
+       }
+
+       bufidx = ++frame & 1;
+
+       y = bufidx ? mode_info->yres : 0;
+       nextaddr = vpgaddr[bufidx];
+
+       when = vsync ? VBE_SET_DISP_START_VBLANK : VBE_SET_DISP_START_NOW;
+       if(vbe_set_disp_start(0, y, when) == -1) {
+               return 0;
+       }
+
+       if(vsync == FLIP_VBLANK_WAIT) {
+               wait_vsync();
+       }
+       return nextaddr;
 }
-#endif
 
 static unsigned int make_mask(int sz, int pos)
 {
@@ -200,6 +203,3 @@ static unsigned int make_mask(int sz, int pos)
        }
        return mask << pos;
 }
-
-
-#endif /* GFX_H_ */