[Xen-devel] [PATCH] qemu sdl blitting

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Hi all,
right now qemu takes care of converting pixels between the guest pixel 
format and the sdl pixel format, after that qemu also memcpy the 
converted pixels to the sdl buffer in video ram.
This process can be improved using the SDL blit capabilities: the patch 
I am attaching creates an SDL Surface from the Cirrus VGA framebuffer 
and uses SDL blitting functions to convert and write pixels to video 
ram. SDL blitting functions are optimized and can even be hardware 
accelerated on some platforms.
Best Regards,

Stefano Stabelllini

diff -r 2a8eaba24bf0 tools/ioemu/hw/vga.c
--- a/tools/ioemu/hw/vga.c      Tue Feb 26 15:11:51 2008 +0000
+++ b/tools/ioemu/hw/vga.c      Fri Feb 29 10:49:17 2008 +0000
@@ -1481,7 +1481,7 @@ static void vga_draw_graphic(VGAState *s
 static void vga_draw_graphic(VGAState *s, int full_update)
 {
     int y1, y, update, linesize, y_start, double_scan, mask, depth;
-    int width, height, shift_control, line_offset, bwidth;
+    int width, height, shift_control, line_offset, bwidth, changed_flag;
     ram_addr_t page0, page1;
     int disp_width, multi_scan, multi_run;
     uint8_t *d;
@@ -1554,10 +1554,12 @@ static void vga_draw_graphic(VGAState *s
     }
     vga_draw_line = vga_draw_line_table[v * NB_DEPTHS + 
get_depth_index(s->ds)];
 
+    changed_flag = 0;
     depth = s->get_bpp(s);
-    if (s->ds->dpy_colourdepth != NULL && s->ds->depth != depth) {
-        if (depth != 24 || s->ds->depth != 32)
+    if (s->ds->dpy_colourdepth != NULL &&
+            (s->ds->depth != depth || !s->ds->shared_buf)) {
             s->ds->dpy_colourdepth(s->ds, depth);
+            changed_flag = 1;
     }
     if (disp_width != s->last_width ||
         height != s->last_height) {
@@ -1567,9 +1569,10 @@ static void vga_draw_graphic(VGAState *s
         s->last_width = disp_width;
         s->last_height = height;
         full_update = 1;
-    }
-    if (s->ds->shared_buf && s->ds->data != s->vram_ptr + (s->start_addr * 4))
-        s->ds->data = s->vram_ptr + (s->start_addr * 4);
+        changed_flag = 1;
+    }
+    if (s->ds->shared_buf && (changed_flag || s->ds->data != s->vram_ptr + 
(s->start_addr * 4)))
+        s->ds->dpy_setdata(s->ds, s->vram_ptr + (s->start_addr * 4));
     if (!s->ds->shared_buf && s->cursor_invalidate)
         s->cursor_invalidate(s);
     
diff -r 2a8eaba24bf0 tools/ioemu/sdl.c
--- a/tools/ioemu/sdl.c Tue Feb 26 15:11:51 2008 +0000
+++ b/tools/ioemu/sdl.c Fri Feb 29 13:08:18 2008 +0000
@@ -30,6 +30,7 @@
 #endif
 
 static SDL_Surface *screen;
+static SDL_Surface *shared = NULL;
 static int gui_grab; /* if true, all keyboard/mouse events are grabbed */
 static int last_vm_running;
 static int gui_saved_grab;
@@ -47,7 +48,46 @@ static void sdl_update(DisplayState *ds,
 static void sdl_update(DisplayState *ds, int x, int y, int w, int h)
 {
     //    printf("updating x=%d y=%d w=%d h=%d\n", x, y, w, h);
-    SDL_UpdateRect(screen, x, y, w, h);
+
+    if (shared) {
+        SDL_Rect rec;
+        rec.x = x;
+        rec.y = y;
+        rec.w = w;
+        rec.h = h;
+        SDL_BlitSurface(shared, &rec, screen, &rec);
+    }
+    SDL_Flip(screen);
+}
+
+static void sdl_setdata(DisplayState *ds, void *pixels)
+{
+    uint32_t rmask, gmask, bmask, amask = 0;
+    switch (ds->depth) {
+        case 8:
+            rmask = 0x000000E0;
+            gmask = 0x0000001C;
+            bmask = 0x00000003;
+            break;
+        case 16:
+            rmask = 0x0000F800;
+            gmask = 0x000007E0;
+            bmask = 0x0000001F;
+            break;
+        case 24:
+            rmask = 0x00FF0000;
+            gmask = 0x0000FF00;
+            bmask = 0x000000FF;
+            break;
+        case 32:
+            rmask = 0x00FF0000;
+            gmask = 0x0000FF00;
+            bmask = 0x000000FF;
+        default:
+            return;
+    }
+    shared = SDL_CreateRGBSurfaceFrom(pixels, width, height, ds->depth, 
ds->linesize, rmask , gmask, bmask, amask);
+    ds->data = pixels;
 }
 
 static void sdl_resize(DisplayState *ds, int w, int h)
@@ -56,7 +96,7 @@ static void sdl_resize(DisplayState *ds,
 
     //    printf("resizing to %d %d\n", w, h);
 
-    flags = SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_HWACCEL;
+    flags = 
SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_HWACCEL|SDL_DOUBLEBUF|SDL_HWPALETTE;
     if (gui_fullscreen)
         flags |= SDL_FULLSCREEN;
 
@@ -78,16 +118,28 @@ static void sdl_resize(DisplayState *ds,
         fprintf(stderr, "Could not open SDL display\n");
         exit(1);
     }
-    ds->data = screen->pixels;
-    ds->linesize = screen->pitch;
-    ds->depth = screen->format->BitsPerPixel;
-    if (ds->depth == 32 && screen->format->Rshift == 0) {
-        ds->bgr = 1;
-    } else {
-        ds->bgr = 0;
-    }
     ds->width = w;
     ds->height = h;
+    if (!ds->shared_buf) {
+        ds->depth = screen->format->BitsPerPixel;
+        if (ds->depth == 32 && screen->format->Rshift == 0) {
+            ds->bgr = 1;
+        } else {
+            ds->bgr = 0;
+        }
+        ds->data = screen->pixels;
+        ds->linesize = screen->pitch;
+    } else {
+        ds->linesize = (ds->depth / 8) * w;
+    }
+}
+
+static void sdl_colourdepth(DisplayState *ds, int depth)
+{
+    if (!depth || !ds->depth) return;
+    ds->shared_buf = 1;
+    ds->depth = depth;
+    ds->linesize = width * depth / 8; 
 }
 
 /* generic keyboard conversion */
@@ -508,7 +560,8 @@ void sdl_display_init(DisplayState *ds, 
     ds->dpy_update = sdl_update;
     ds->dpy_resize = sdl_resize;
     ds->dpy_refresh = sdl_refresh;
-    ds->dpy_colourdepth = NULL;
+    ds->dpy_colourdepth = sdl_colourdepth;
+    ds->dpy_setdata = sdl_setdata;
 
     sdl_resize(ds, 640, 400);
     sdl_update_caption();
diff -r 2a8eaba24bf0 tools/ioemu/vl.h
--- a/tools/ioemu/vl.h  Tue Feb 26 15:11:51 2008 +0000
+++ b/tools/ioemu/vl.h  Wed Feb 27 14:39:15 2008 +0000
@@ -940,6 +940,7 @@ struct DisplayState {
     void (*dpy_update)(struct DisplayState *s, int x, int y, int w, int h);
     void (*dpy_resize)(struct DisplayState *s, int w, int h);
     void (*dpy_colourdepth)(struct DisplayState *s, int depth);
+    void (*dpy_setdata)(DisplayState *ds, void *pixels);
     void (*dpy_refresh)(struct DisplayState *s);
     void (*dpy_copy)(struct DisplayState *s, int src_x, int src_y, int dst_x, 
int dst_y, int w, int h);
 };
diff -r 2a8eaba24bf0 tools/ioemu/vnc.c
--- a/tools/ioemu/vnc.c Tue Feb 26 15:11:51 2008 +0000
+++ b/tools/ioemu/vnc.c Fri Feb 29 11:43:27 2008 +0000
@@ -1621,6 +1621,11 @@ static void pixel_format_message (VncSta
     vnc_write(vs, pad, 3);           /* padding */
 }
 
+static void vnc_dpy_setdata(DisplayState *ds, void *pixels)
+{
+    ds->data = pixels;
+}
+
 static void vnc_dpy_colourdepth(DisplayState *ds, int depth)
 {
     int host_big_endian_flag;
@@ -1628,6 +1633,7 @@ static void vnc_dpy_colourdepth(DisplayS
 
     switch (depth) {
         case 24:
+            if (ds->depth == 32) return;
             ds->shared_buf = 0;
             depth = 32;
             break;
@@ -2480,6 +2486,7 @@ void vnc_display_init(DisplayState *ds)
     vs->ds->dpy_update = vnc_dpy_update;
     vs->ds->dpy_resize = vnc_dpy_resize;
     vs->ds->dpy_colourdepth = vnc_dpy_colourdepth;
+    vs->ds->dpy_setdata = vnc_dpy_setdata;
     vs->ds->dpy_refresh = vnc_dpy_refresh;
 
     vs->ds->width = 640;

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