| Message ID | 20180216115410.27287-5-kraxel@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PULL,1/9] vnc: remove bogus object_unref on client socket | expand |
On 16 February 2018 at 11:54, Gerd Hoffmann <kraxel@redhat.com> wrote: > From: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> > > The documentation on SDL_RenderPresent function states that > "the backbuffer should be considered invalidated after each present", > so copy the entire texture on each redraw. > > On the other hand, SDL_UpdateTexture function is described as > "fairly slow function", so restrict it to just the changed pixels. > > Also added SDL_RenderClear call, as suggested in the documentation > page on SDL_RenderPresent. > > Signed-off-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> > Message-id: 20180205133228.25082-1-anatoly.trosinenko@gmail.com > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> > --- > ui/sdl2-2d.c | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > diff --git a/ui/sdl2-2d.c b/ui/sdl2-2d.c > index 8ab68d67b9..1f34817bae 100644 > --- a/ui/sdl2-2d.c > +++ b/ui/sdl2-2d.c > @@ -36,6 +36,8 @@ void sdl2_2d_update(DisplayChangeListener *dcl, > struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl); > DisplaySurface *surf = qemu_console_surface(dcl->con); > SDL_Rect rect; > + size_t surface_data_offset = surface_bytes_per_pixel(surf) * x + > + surface_stride(surf) * y; > > assert(!scon->opengl); > Hi. Coverity points out (CID 1390598) that this change adds a use of 'surf' before the "if (!surf) { return; }" check. I suspect the calculation of surface_data_offset should be done lower in the function, after all the early-exit checks. thanks -- PMM
diff --git a/ui/sdl2-2d.c b/ui/sdl2-2d.c index 8ab68d67b9..1f34817bae 100644 --- a/ui/sdl2-2d.c +++ b/ui/sdl2-2d.c @@ -36,6 +36,8 @@ void sdl2_2d_update(DisplayChangeListener *dcl, struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl); DisplaySurface *surf = qemu_console_surface(dcl->con); SDL_Rect rect; + size_t surface_data_offset = surface_bytes_per_pixel(surf) * x + + surface_stride(surf) * y; assert(!scon->opengl); @@ -46,27 +48,16 @@ void sdl2_2d_update(DisplayChangeListener *dcl, return; } - /* - * SDL2 seems to do some double-buffering, and trying to only - * update the changed areas results in only one of the two buffers - * being updated. Which flickers alot. So lets not try to be - * clever do a full update every time ... - */ -#if 0 rect.x = x; rect.y = y; rect.w = w; rect.h = h; -#else - rect.x = 0; - rect.y = 0; - rect.w = surface_width(surf); - rect.h = surface_height(surf); -#endif - SDL_UpdateTexture(scon->texture, NULL, surface_data(surf), + SDL_UpdateTexture(scon->texture, &rect, + surface_data(surf) + surface_data_offset, surface_stride(surf)); - SDL_RenderCopy(scon->real_renderer, scon->texture, &rect, &rect); + SDL_RenderClear(scon->real_renderer); + SDL_RenderCopy(scon->real_renderer, scon->texture, NULL, NULL); SDL_RenderPresent(scon->real_renderer); }