[libcamera-devel] [PATCH] cam: sdl: Use uint32_t in place of SDL_PixelFormatEnum

[Jacopo Mondi]

Hi Kieran

On Fri, Jul 15, 2022 at 09:22:15AM +0100, Kieran Bingham wrote:
> Quoting Jacopo Mondi via libcamera-devel (2022-07-14 19:24:23)
> > The SDL_PixelFormatEnum type has been introduced in libsdl by
> > 1a4c0d4e17e6 ("Fixed bug 4377 - SDL_PIXELFORMAT enum is anonymous, which
> > prevents its use in a templated function") which is only available after
> > release 2.0.10 of the library.
> >
> > Debian 10 ships libsdl at version 2.0.9 and building cam with sdl
> > support there fails with error:
> > ./src/cam/sdl_texture.h:27:8: error: ‘SDL_PixelFormatEnum’ does not name
> > a type; did you mean ‘SDL_PixelFormat’?
> >
> > Fix that by using the base type uint32_t in place of
> > SDL_PixelFormatEnum.
>
> Is there scope to fix this by checking the version of the header being
> compiled and defining SDL_PixelFormatEnum instead?
>
> I would expect something in src/cam/sdl_texture.h such as:
>
> #if !SDL_VERSION_ATLEAST(2.0.10)
> typedef uint32_t SDL_PixelFormatEnum;
> #endif
>

I don't see any benefit to be honest.

The library itself uses uint32 in it's public API

/**
 * Convert one of the enumerated pixel formats to a bpp value and RGBA masks.
 *
 * \param format one of the SDL_PixelFormatEnum values
 * \param bpp a bits per pixel value; usually 15, 16, or 32
 * \param Rmask a pointer filled in with the red mask for the format
 * \param Gmask a pointer filled in with the green mask for the format
 * \param Bmask a pointer filled in with the blue mask for the format
 * \param Amask a pointer filled in with the alpha mask for the format
 * \returns SDL_TRUE on success or SDL_FALSE if the conversion wasn't
 *          possible; call SDL_GetError() for more information.
 *
 * \since This function is available since SDL 2.0.0.
 *
 * \sa SDL_MasksToPixelFormatEnum
 */
extern DECLSPEC SDL_bool SDLCALL SDL_PixelFormatEnumToMasks(Uint32 format,
                                                            int *bpp,
                                                            Uint32 * Rmask,
                                                            Uint32 * Gmask,
                                                            Uint32 * Bmask,
                                                            Uint32 * Amask);


Looking at commit history libsdl is also progressively removing the
"Enum" suffix from their defined types, I would not tie ourselves to
such moving parts for no benefit.



>
> --
> Kieran
>
>
> > Reported-by: https://buildbot.libcamera.org/#/builders/6/builds/355
> > Fixes: 11554a259f4e ("cam: sdl_sink: Add SDL sink with initial YUYV support")
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >  src/cam/sdl_texture.cpp | 2 +-
> >  src/cam/sdl_texture.h   | 4 ++--
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/src/cam/sdl_texture.cpp b/src/cam/sdl_texture.cpp
> > index 2ca2add2f00c..02a8ff28b669 100644
> > --- a/src/cam/sdl_texture.cpp
> > +++ b/src/cam/sdl_texture.cpp
> > @@ -9,7 +9,7 @@
> >
> >  #include <iostream>
> >
> > -SDLTexture::SDLTexture(const SDL_Rect &rect, SDL_PixelFormatEnum pixelFormat,
> > +SDLTexture::SDLTexture(const SDL_Rect &rect, uint32_t pixelFormat,
> >                        const int pitch)
> >         : ptr_(nullptr), rect_(rect), pixelFormat_(pixelFormat), pitch_(pitch)
> >  {
> > diff --git a/src/cam/sdl_texture.h b/src/cam/sdl_texture.h
> > index 9097479846f7..2275b4e605d9 100644
> > --- a/src/cam/sdl_texture.h
> > +++ b/src/cam/sdl_texture.h
> > @@ -14,7 +14,7 @@
> >  class SDLTexture
> >  {
> >  public:
> > -       SDLTexture(const SDL_Rect &rect, SDL_PixelFormatEnum pixelFormat,
> > +       SDLTexture(const SDL_Rect &rect, uint32_t pixelFormat,
> >                    const int pitch);
> >         virtual ~SDLTexture();
> >         int create(SDL_Renderer *renderer);
> > @@ -24,6 +24,6 @@ public:
> >  protected:
> >         SDL_Texture *ptr_;
> >         const SDL_Rect rect_;
> > -       const SDL_PixelFormatEnum pixelFormat_;
> > +       const uint32_t pixelFormat_;
> >         const int pitch_;
> >  };
> > --
> > 2.36.1
> >