[PATCH v2 3/4] apps: cam: sdl_texture: Add `SDLTexture1Plane`

[Laurent Pinchart]

On Fri, Apr 25, 2025 at 02:59:18PM +0200, Barnabás Pőcze wrote:
> 2025. 04. 25. 14:41 keltezéssel, Laurent Pinchart írta:
> > On Fri, Apr 25, 2025 at 12:47:02PM +0200, Barnabás Pőcze wrote:
> >> `SDLTextureYUYV` uses `SDL_PIXELFORMAT_YUY2`, which is a single plane
> >> format. To support other single plane formats, replace `SDLTextureYUYV`
> >> with `SDLTexture1Plane` that can be instantiated with an arbitrary SDL
> >> pixel format and that uses `SDL_UpdateTexture()` to update the texture
> >> using exactly a single plane.
> >>
> >> Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
> >> ---
> >>   src/apps/cam/sdl_sink.cpp         |  3 ++-
> >>   src/apps/cam/sdl_texture_1plane.h | 18 ++++++++++++++++++
> >>   src/apps/cam/sdl_texture_yuv.cpp  | 10 ----------
> >>   src/apps/cam/sdl_texture_yuv.h    |  7 -------
> >>   4 files changed, 20 insertions(+), 18 deletions(-)
> >>   create mode 100644 src/apps/cam/sdl_texture_1plane.h
> >>
> >> diff --git a/src/apps/cam/sdl_sink.cpp b/src/apps/cam/sdl_sink.cpp
> >> index 8355dd5ed..b295675dc 100644
> >> --- a/src/apps/cam/sdl_sink.cpp
> >> +++ b/src/apps/cam/sdl_sink.cpp
> >> @@ -22,6 +22,7 @@
> >>   #include "../common/event_loop.h"
> >>   #include "../common/image.h"
> >>   
> >> +#include "sdl_texture_1plane.h"
> >>   #ifdef HAVE_LIBJPEG
> >>   #include "sdl_texture_mjpg.h"
> >>   #endif
> >> @@ -74,7 +75,7 @@ int SDLSink::configure(const libcamera::CameraConfiguration &config)
> >>   		break;
> >>   #endif
> >>   	case libcamera::formats::YUYV:
> >> -		texture_ = std::make_unique<SDLTextureYUYV>(rect_, cfg.stride);
> >> +		texture_ = std::make_unique<SDLTexture1Plane>(rect_, SDL_PIXELFORMAT_YUY2, cfg.stride);
> >>   		break;
> >>   	default:
> >>   		std::cerr << "Unsupported pixel format "
> >> diff --git a/src/apps/cam/sdl_texture_1plane.h b/src/apps/cam/sdl_texture_1plane.h
> >> new file mode 100644
> >> index 000000000..ded35c589
> >> --- /dev/null
> >> +++ b/src/apps/cam/sdl_texture_1plane.h
> >> @@ -0,0 +1,18 @@
> >> +#pragma once
> >> +
> >> +#include <assert.h>
> >> +
> >> +#include "sdl_texture.h"
> >> +
> >> +class SDLTexture1Plane final : public SDLTexture
> >> +{
> >> +public:
> >> +	using SDLTexture::SDLTexture;
> >> +
> >> +	void update(libcamera::Span<const libcamera::Span<const uint8_t>> data) override
> >> +	{
> >> +		assert(data.size() == 1);
> >> +		assert(data[0].size_bytes() == std::size_t(rect_.h * stride_));
> >> +		SDL_UpdateTexture(ptr_, nullptr, data[0].data(), stride_);
> >> +	}
> > 
> > Do we need to inline this function, can't it go to a .cpp file ?
> 
> It could certainly be in a cpp file, I can move it if you want me to. I just kept it here
> for simplicity and because it is only used in a single cpp file.

It would be more consistent with the rest of the code base. I can also
pretend not to have noticed, but maybe you want to keep that joker card
for a future patch instead of using it here :-)

> > With that handled,
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > 
> >> +};
> >> diff --git a/src/apps/cam/sdl_texture_yuv.cpp b/src/apps/cam/sdl_texture_yuv.cpp
> >> index 7e2ce3f49..bed297d28 100644
> >> --- a/src/apps/cam/sdl_texture_yuv.cpp
> >> +++ b/src/apps/cam/sdl_texture_yuv.cpp
> >> @@ -21,13 +21,3 @@ void SDLTextureNV12::update(libcamera::Span<const libcamera::Span<const uint8_t>
> >>   			    data[1].data(), stride_);
> >>   }
> >>   #endif
> >> -
> >> -SDLTextureYUYV::SDLTextureYUYV(const SDL_Rect &rect, unsigned int stride)
> >> -	: SDLTexture(rect, SDL_PIXELFORMAT_YUY2, stride)
> >> -{
> >> -}
> >> -
> >> -void SDLTextureYUYV::update(libcamera::Span<const libcamera::Span<const uint8_t>> data)
> >> -{
> >> -	SDL_UpdateTexture(ptr_, nullptr, data[0].data(), stride_);
> >> -}
> >> diff --git a/src/apps/cam/sdl_texture_yuv.h b/src/apps/cam/sdl_texture_yuv.h
> >> index db877f503..c271f901b 100644
> >> --- a/src/apps/cam/sdl_texture_yuv.h
> >> +++ b/src/apps/cam/sdl_texture_yuv.h
> >> @@ -17,10 +17,3 @@ public:
> >>   	void update(libcamera::Span<const libcamera::Span<const uint8_t>> data) override;
> >>   };
> >>   #endif
> >> -
> >> -class SDLTextureYUYV : public SDLTexture
> >> -{
> >> -public:
> >> -	SDLTextureYUYV(const SDL_Rect &rect, unsigned int stride);
> >> -	void update(libcamera::Span<const libcamera::Span<const uint8_t>> data) override;
> >> -};

-- 
Regards,

Laurent Pinchart