Hi Marc-André,
On 07/06/2023 12:21, Marc-André Lureau wrote:
> Hi Antonio
>
> On Wed, Jun 7, 2023 at 1:05 PM Antonio Caggiano <quic_acaggian@quicinc.com>
> wrote:
>
>> Add the SDL_WINDOW_ALLOW_HIGHDPI flag when creating a window and get the
>> drawable size instead of the window size when setting up the framebuffer
>> and the viewport.
>>
>>
> What does this actually change?
The sdl2-gl backend does not work properly on high-DPI windows. [0]
My understanding is that by allowing high-DPI, SDL creates a framebuffer
with the right size in pixels which might be different than the size of
the window. [1]
I believe we just need to use the framebuffer size for GL viewport and
texture, by retrieving it with SDL_GL_GetDrawableSize.
> What about non-gl display, Mouse motion, and display resize?
From what I can see by testing the SDL2 renderer, it seems to handle
all of this transparently, so there is nothing we need to do in sdl2-2d.
Same for mouse motion, which I believe is using window "screen coordinates".
Display resize is a bit weird for a bunch of frames, but then it fixes
itself.
[0]
https://user-images.githubusercontent.com/6058008/244368628-329241dc-267d-452f-b8ce-816ae1623131.png
I am using SDL2-2.26.3-1.fc38.x86_64 on wayland, and it doesn't have this issue.
Your patch doesn't seem to change the behaviour.
Maybe there is something to investigate at SDL level instead.
btw, "allow hi-dpi" isn't a good description imho, since the guest still doesn't receive real physical hi-dpi details of the client, and remains scaled-up.
[1] https://wiki.libsdl.org/SDL2/SDL_GetWindowSize#remarks
>
> thanks
>
> Signed-off-by: Antonio Caggiano <quic_acaggian@quicinc.com>
>> ---
>> ui/sdl2-gl.c | 4 ++--
>> ui/sdl2.c | 2 +-
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
>> index bbfa70eac3..251b7d56d6 100644
>> --- a/ui/sdl2-gl.c
>> +++ b/ui/sdl2-gl.c
>> @@ -53,7 +53,7 @@ static void sdl2_gl_render_surface(struct sdl2_console
>> *scon)
>> SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
>> sdl2_set_scanout_mode(scon, false);
>>
>> - SDL_GetWindowSize(scon->real_window, &ww, &wh);
>> + SDL_GL_GetDrawableSize(scon->real_window, &ww, &wh);
>> surface_gl_setup_viewport(scon->gls, scon->surface, ww, wh);
>>
>> surface_gl_render_texture(scon->gls, scon->surface);
>> @@ -239,7 +239,7 @@ void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
>>
>> SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
>>
>> - SDL_GetWindowSize(scon->real_window, &ww, &wh);
>> + SDL_GL_GetDrawableSize(scon->real_window, &ww, &wh);
>> egl_fb_setup_default(&scon->win_fb, ww, wh);
>> egl_fb_blit(&scon->win_fb, &scon->guest_fb, !scon->y0_top);
>>
>> diff --git a/ui/sdl2.c b/ui/sdl2.c
>> index 9d703200bf..c9c83815ca 100644
>> --- a/ui/sdl2.c
>> +++ b/ui/sdl2.c
>> @@ -95,7 +95,7 @@ void sdl2_window_create(struct sdl2_console *scon)
>> }
>> #ifdef CONFIG_OPENGL
>> if (scon->opengl) {
>> - flags |= SDL_WINDOW_OPENGL;
>> + flags |= SDL_WINDOW_OPENGL | SDL_WINDOW_ALLOW_HIGHDPI;
>> }
>> #endif
>>
>> --
>> 2.40.0
>>
>>
>
Cheers,
Antonio