[libcamera-devel] [PATCH v4] cam: sdl_sink: Add SDL sink
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Tue Mar 29 17:09:58 CEST 2022
Hi Eric,
Thank you for the patch.
On Tue, Mar 29, 2022 at 12:17:25PM +0100, Eric Curtin via libcamera-devel wrote:
> This adds more portability to existing cam sinks. You can pass a
> YUYV camera buffer for example and SDL will handle the pixel buffer
> conversion, although SDL does not support decompression for pixelformats
> like MJPEG. This allows cam reference implementation to display images
> on VMs, Mac M1, Raspberry Pi, etc. This also enables cam reference
> implementation, to run as a desktop application in wayland or x11.
> SDL also has support for Android and ChromeOS which I have not tested.
> Also tested on simpledrm raspberry pi 4 framebuffer successfully where
> existing kms sink did not work. Can also be used as kmsdrm sink.
>
> Signed-off-by: Eric Curtin <ecurtin at redhat.com>
> ---
> Changes in v2:
> - Remove hardcoded pixel format from SDL_CreateTexture call
>
> Changes in v3:
> - Drop blank line
> - The contents of the if..endif are indented
> - Split configure function into start and configure
> - Add SDL_DestroyRenderer
> - Remove assign and test in the same statement
>
> Changes in v4:
> - Add processSDLEvents as a timed event in the evloop
> ---
> src/cam/camera_session.cpp | 8 +++
> src/cam/event_loop.cpp | 10 ++-
> src/cam/event_loop.h | 1 +
> src/cam/main.cpp | 5 ++
> src/cam/main.h | 1 +
> src/cam/meson.build | 10 +++
> src/cam/sdl_sink.cpp | 142 +++++++++++++++++++++++++++++++++++++
> src/cam/sdl_sink.h | 42 +++++++++++
> 8 files changed, 218 insertions(+), 1 deletion(-)
> create mode 100644 src/cam/sdl_sink.cpp
> create mode 100644 src/cam/sdl_sink.h
>
> diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
> index 0428b538..30162dbd 100644
> --- a/src/cam/camera_session.cpp
> +++ b/src/cam/camera_session.cpp
> @@ -19,6 +19,9 @@
> #ifdef HAVE_KMS
> #include "kms_sink.h"
> #endif
> +#ifdef HAVE_SDL
> +#include "sdl_sink.h"
> +#endif
> #include "main.h"
> #include "stream_options.h"
>
> @@ -187,6 +190,11 @@ int CameraSession::start()
> sink_ = std::make_unique<KMSSink>(options_[OptDisplay].toString());
> #endif
>
> +#ifdef HAVE_SDL
> + if (options_.isSet(OptSDL))
> + sink_ = std::make_unique<SDLSink>();
> +#endif
> +
> if (options_.isSet(OptFile)) {
> if (!options_[OptFile].toString().empty())
> sink_ = std::make_unique<FileSink>(streamNames_,
> diff --git a/src/cam/event_loop.cpp b/src/cam/event_loop.cpp
> index e25784c0..41339d4e 100644
> --- a/src/cam/event_loop.cpp
> +++ b/src/cam/event_loop.cpp
> @@ -75,7 +75,15 @@ void EventLoop::addEvent(int fd, EventType type,
> return;
> }
>
> - int ret = event_add(event->event_, nullptr);
> + struct timeval *tp = nullptr;
> + struct timeval tv;
> + if (events == EV_PERSIST) {
> + tp = &tv;
> + tv.tv_sec = 0;
> + tv.tv_usec = 10000; /* every 10 ms */
> + }
Could you please split the change to the event loop to a separate patch,
with an explanation of what it does in the commit message ? This isn't
trivial to understand.
> +
> + int ret = event_add(event->event_, tp);
> if (ret < 0) {
> std::cerr << "Failed to add event for fd " << fd << std::endl;
> return;
> diff --git a/src/cam/event_loop.h b/src/cam/event_loop.h
> index a4613eb2..8fd9bd20 100644
> --- a/src/cam/event_loop.h
> +++ b/src/cam/event_loop.h
> @@ -20,6 +20,7 @@ class EventLoop
> {
> public:
> enum EventType {
> + Default = 0, /* the event can be triggered only by a timeout or by manual activation */
> Read = 1,
> Write = 2,
> };
> diff --git a/src/cam/main.cpp b/src/cam/main.cpp
> index c7f664b9..1d62a64a 100644
> --- a/src/cam/main.cpp
> +++ b/src/cam/main.cpp
> @@ -137,6 +137,11 @@ int CamApp::parseOptions(int argc, char *argv[])
> "Display viewfinder through DRM/KMS on specified connector",
> "display", ArgumentOptional, "connector", false,
> OptCamera);
> +#endif
> +#ifdef HAVE_SDL
> + parser.addOption(OptSDL, OptionNone,
> + "Display viewfinder through SDL",
> + "sdl", ArgumentNone, "", false, OptCamera);
> #endif
> parser.addOption(OptFile, OptionString,
> "Write captured frames to disk\n"
> diff --git a/src/cam/main.h b/src/cam/main.h
> index 62f7bbc9..a64f95a0 100644
> --- a/src/cam/main.h
> +++ b/src/cam/main.h
> @@ -11,6 +11,7 @@ enum {
> OptCamera = 'c',
> OptCapture = 'C',
> OptDisplay = 'D',
> + OptSDL = 'S',
Let's keep the options sorted.
> OptFile = 'F',
> OptHelp = 'h',
> OptInfo = 'I',
> diff --git a/src/cam/meson.build b/src/cam/meson.build
> index e8e2ae57..bd536c5b 100644
> --- a/src/cam/meson.build
> +++ b/src/cam/meson.build
> @@ -32,11 +32,21 @@ cam_sources += files([
> ])
> endif
>
> +libsdl2 = dependency('SDL2', required : false)
> +
> +if libsdl2.found()
> + cam_cpp_args += [ '-DHAVE_SDL' ]
No space within the [ ].
> + cam_sources += files([
> + 'sdl_sink.cpp'
> + ])
> +endif
> +
> cam = executable('cam', cam_sources,
> dependencies : [
> libatomic,
> libcamera_public,
> libdrm,
> + libsdl2,
> libevent,
> ],
> cpp_args : cam_cpp_args,
> diff --git a/src/cam/sdl_sink.cpp b/src/cam/sdl_sink.cpp
> new file mode 100644
> index 00000000..6c6e37d0
> --- /dev/null
> +++ b/src/cam/sdl_sink.cpp
> @@ -0,0 +1,142 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * sdl_sink.cpp - SDL Sink
> + */
> +
> +#include "sdl_sink.h"
> +
> +#include <assert.h>
> +#include <fcntl.h>
> +#include <iomanip>
> +#include <iostream>
> +#include <signal.h>
> +#include <sstream>
> +#include <string.h>
> +#include <unistd.h>
> +
> +#include <libcamera/camera.h>
> +#include <libcamera/formats.h>
> +
> +#include "event_loop.h"
> +#include "image.h"
> +
> +using namespace libcamera;
> +
> +SDLSink::SDLSink()
> + : sdlRenderer_(0)
It's a pointer, should be initialized to nullptr, not 0.
> +{
> + memset(&sdlRect_, 0, sizeof(sdlRect_));
This could be initialized with
sdlRect_({})
in the constructor member initializers list.
> +}
> +
> +SDLSink::~SDLSink()
> +{
> + if (sdlRenderer_)
> + SDL_DestroyRenderer(sdlRenderer_);
> + SDL_Quit();
Shouldn't the cleanup go to stop(), now that you have the initialization
in start() ?
No need for any cleanup on sdlScreen_ and sdlTexture_ ?
> +}
> +
> +int SDLSink::configure(const libcamera::CameraConfiguration &cfg)
> +{
> + int ret = FrameSink::configure(cfg);
> + if (ret < 0)
> + return ret;
> +
> + const libcamera::StreamConfiguration &sCfg = cfg.at(0);
> + pf = (SDL_PixelFormatEnum)sCfg.pixelFormat.fourcc();
> + if (pf == SDL_DEFINE_PIXELFOURCC('Y', 'U', 'Y', 'V')) {
> + pf = SDL_PIXELFORMAT_YUY2;
> + } else if (int ne = strcmp(SDL_GetPixelFormatName(pf), "SDL_PIXELFORMAT_UNKNOWN"); !ne) {
No variable declaration in an if () statement.
> + std::cerr << "SDL_GetPixelFormatName error - exiting: SDL_PIXELFORMAT_UNKNOWN, no " << sCfg.pixelFormat.toString() << " support\n";
Those two lines are too long.
Replace \n with std::endl
> + return -EINVAL;
> + }
I don't think this is right. SDL pixel formats don't map directly to the
4CC values used by libcamera. You need a translation table.
> +
> + sdlRect_.w = sCfg.size.width;
> + sdlRect_.h = sCfg.size.height;
> +
> + return 0;
> +}
> +
> +int SDLSink::start()
> +{
> + int ret = SDL_Init(SDL_INIT_VIDEO);
> + if (ret) {
> + std::cerr << "SDL_Init error - exiting: " << SDL_GetError() << std::endl;
std::cerr << "Failed to initialize SDL: " << SDL_GetError()
<< std::endl;
and similarly below.
> + return ret;
> + }
> +
> + sdlScreen_ = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED,
> + SDL_WINDOWPOS_UNDEFINED, sdlRect_.w,
> + sdlRect_.h, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
> + if (!sdlScreen_) {
> + std::cerr << "SDL_CreateWindow error - exiting: " << SDL_GetError() << std::endl;
> + return -EINVAL;
> + }
> +
> + sdlRenderer_ = SDL_CreateRenderer(
> + sdlScreen_, -1, 0);
> + if (!sdlRenderer_) {
> + std::cerr << "SDL_CreateRenderer error - exiting: " << SDL_GetError() << std::endl;
> + return -EINVAL;
> + }
> +
> + SDL_RenderSetLogicalSize(sdlRenderer_, sdlRect_.w,
> + sdlRect_.h);
> +
> + sdlTexture_ =
> + SDL_CreateTexture(sdlRenderer_, pf,
> + SDL_TEXTUREACCESS_STREAMING, sdlRect_.w,
> + sdlRect_.h);
> + EventLoop::instance()->addEvent(-1, EventLoop::Default,
> + std::bind(&SDLSink::processSDLEvents, this));
> +
> + return 0;
> +}
> +
> +void SDLSink::mapBuffer(FrameBuffer *buffer)
> +{
> + std::unique_ptr<Image> image =
> + Image::fromFrameBuffer(buffer, Image::MapMode::ReadOnly);
> + assert(image != nullptr);
> +
> + mappedBuffers_[buffer] = std::move(image);
> +}
> +
> +bool SDLSink::processRequest(Request *request)
> +{
> + for (auto [stream, buffer] : request->buffers())
> + writeBuffer(buffer);
Will this really work properly if the request contains multiple buffers
?
> +
> + return true;
> +}
> +
> +/*
> + * Process SDL events, required for things like window resize and quit button
> + */
> +void SDLSink::processSDLEvents()
> +{
> + for (SDL_Event e; SDL_PollEvent(&e);) {
> + if (e.type == SDL_QUIT) { /* click close icon then quit */
> + kill(getpid(), SIGINT);
That's too harsh. Calling the exit() function of the event loop should
be enough.
> + }
> + }
> +}
> +
> +void SDLSink::writeBuffer(FrameBuffer *buffer)
This function doesn't "write" a buffer, it should be named differently.
> +{
> + Image *image = mappedBuffers_[buffer].get();
> +
> + for (unsigned int i = 0; i < buffer->planes().size(); ++i) {
> + const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
> +
> + Span<uint8_t> data = image->data(i);
> + if (meta.bytesused > data.size())
> + std::cerr << "payload size " << meta.bytesused
> + << " larger than plane size " << data.size()
> + << std::endl;
> +
> + SDL_UpdateTexture(sdlTexture_, &sdlRect_, data.data(), sdlRect_.w * 2);
Is the last argument format-dependent ?
> + SDL_RenderClear(sdlRenderer_);
> + SDL_RenderCopy(sdlRenderer_, sdlTexture_, NULL, NULL);
s/NULL/nullptr/
> + SDL_RenderPresent(sdlRenderer_);
> + }
> +}
> diff --git a/src/cam/sdl_sink.h b/src/cam/sdl_sink.h
> new file mode 100644
> index 00000000..6f20e2d6
> --- /dev/null
> +++ b/src/cam/sdl_sink.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * sdl_sink.h - SDL Sink
> + */
> +
> +#pragma once
> +
> +#include <map>
> +#include <memory>
> +#include <string>
> +
> +#include <libcamera/stream.h>
> +
> +#include <SDL2/SDL.h>
> +
> +#include "frame_sink.h"
> +
> +class Image;
> +
> +class SDLSink : public FrameSink
> +{
> +public:
> + SDLSink();
> + ~SDLSink();
> +
> + int configure(const libcamera::CameraConfiguration &cfg) override;
> + int start() override;
> + void mapBuffer(libcamera::FrameBuffer *buffer) override;
> +
> + bool processRequest(libcamera::Request *request) override;
> +
> +private:
> + void writeBuffer(libcamera::FrameBuffer *buffer);
> + void processSDLEvents();
> +
> + std::map<libcamera::FrameBuffer *, std::unique_ptr<Image>> mappedBuffers_;
I'd add a blank line here.
> + SDL_Window *sdlScreen_;
> + SDL_Renderer *sdlRenderer_;
> + SDL_Texture *sdlTexture_;
> + SDL_Rect sdlRect_;
> + SDL_PixelFormatEnum pf;
s/pf/pixelFormat_/
> +};
--
Regards,
Laurent Pinchart
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