[PATCH v2 4/4] apps: cam: sdl_sink: Support more single-plane formats

[Laurent Pinchart]

On Mon, Apr 28, 2025 at 10:52:39AM +0200, Barnabás Pőcze wrote:
> 2025. 04. 25. 16:41 keltezéssel, Laurent Pinchart írta:
> > On Fri, Apr 25, 2025 at 02:58:08PM +0200, Barnabás Pőcze wrote:
> >> 2025. 04. 25. 14:45 keltezéssel, Laurent Pinchart írta:
> >>> On Fri, Apr 25, 2025 at 12:47:03PM +0200, Barnabás Pőcze wrote:
> >>>> With the newly introduced `SDLTexture1Plane` it is easy to handle
> >>>> any single-plane format that has an SDL equivalent. So use it for
> >>>> more YUV and RGB formats.
> >>>>
> >>>> The mapping of RGB formats is not entirely straightforward because
> >>>> `SDL_PIXELFORMAT_ZZZ...888...` defines a format where the order of
> >>>> the components is endian dependent, while libcamera's `ZZZ...888...`
> >>>> formats are derived from the matching DRM formats, and the RGB formats
> >>>> in question are defined to be little-endian there. So the
> >>>> endian-independent `SDL_PIXELFORMAT_{ZZZ24,ZZZZ32}` are used.
> >>>
> >>> Format mapping is always painful :-(
> >>>
> >>>> Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
> >>>> ---
> >>>>    src/apps/cam/sdl_sink.cpp | 36 ++++++++++++++++++++++++++++++++++++
> >>>>    1 file changed, 36 insertions(+)
> >>>>
> >>>> diff --git a/src/apps/cam/sdl_sink.cpp b/src/apps/cam/sdl_sink.cpp
> >>>> index b295675dc..2edbb523d 100644
> >>>> --- a/src/apps/cam/sdl_sink.cpp
> >>>> +++ b/src/apps/cam/sdl_sink.cpp
> >>>> @@ -77,6 +77,42 @@ int SDLSink::configure(const libcamera::CameraConfiguration &config)
> >>>>    	case libcamera::formats::YUYV:
> >>>>    		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_YUY2, cfg.stride);
> >>>>    		break;
> >>>> +	case libcamera::formats::UYVY:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_UYVY, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::YVYU:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_YVYU, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::ARGB8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_BGRA32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::XRGB8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_BGRX32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::RGBA8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_ABGR32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::RGBX8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_XBGR32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::ABGR8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_RGBA32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::XBGR8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_RGBX32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::BGRA8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_ARGB32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::BGRX8888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_XRGB32, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::RGB888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_BGR24, cfg.stride);
> >>>> +		break;
> >>>> +	case libcamera::formats::BGR888:
> >>>> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_RGB24, cfg.stride);
> >>>> +		break;
> >>>
> >>> I'm tempted to avoid all the constructor calls by instead adding a
> >>> sdlFormat variable and filling it in the switch, and then creating the
> >>> texture after the switch.
> >>
> >> Yes, indeed, and I had thought about that for a bit, but there is also
> >> SDLTextureNV12 (conditionally), and I didn't really see a good way to
> >> reconcile the two.
> > 
> > 
> > 	switch (cfg.pixelFormat) {
> > #ifdef HAVE_LIBJPEG
> > 	case libcamera::formats::MJPEG:
> > 		texture_ = std::make_unique<SDLTextureMJPG>(rect_);
> > 		break;
> > #endif
> > #if SDL_VERSION_ATLEAST(2, 0, 16)
> > 	case libcamera::formats::NV12:
> > 		texture_ = std::make_unique<SDLTextureNV12>(rect_, cfg.stride);
> > 		break;
> > #endif
> >   	case libcamera::formats::YUYV:
> >   		sdlFormat = SDL_PIXELFORMAT_YUY2;
> >   		break;
> > 	case libcamera::formats::UYVY:
> >   		sdlFormat = SDL_PIXELFORMAT_UYVY;
> > 		break;
> > ...
> > 	default:
> > 		std::cerr << "Unsupported pixel format "
> > 			  << cfg.pixelFormat.toString() << std::endl;
> > 		return -EINVAL;
> > 	};
> > 
> > 	if (sdlFormat)
> > 		texture_ = std::make_unique<SDLTexture1Plane>(rect_, sdlFormat, cfg.stride);
> > 
> 
> I have looked at something like this, but I am not a fan at all. :(

I understand why and I probably have the same feeling. I still think
it's a bit better than duplicating the calls though.

> >>> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> >>>
> >>>>    	default:
> >>>>    		std::cerr << "Unsupported pixel format "
> >>>>    			  << cfg.pixelFormat.toString() << std::endl;

-- 
Regards,

Laurent Pinchart