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

[Kieran Bingham]

Quoting Barnabás Pőcze (2025-04-25 11:47:02)
> `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>

Looks neat,


Reviewed-by: Kieran Bingham <kieran.bingham 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_);
> +       }
> +};
> 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;
> -};
> -- 
> 2.49.0
>