[libcamera-devel] [PATCH v4] cam: sdl_sink: Add SDL sink
Eric Curtin
ecurtin at redhat.com
Tue Mar 29 13:17:25 CEST 2022
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 */
+ }
+
+ 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',
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' ]
+ 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)
+{
+ memset(&sdlRect_, 0, sizeof(sdlRect_));
+}
+
+SDLSink::~SDLSink()
+{
+ if (sdlRenderer_)
+ SDL_DestroyRenderer(sdlRenderer_);
+ SDL_Quit();
+}
+
+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) {
+ std::cerr << "SDL_GetPixelFormatName error - exiting: SDL_PIXELFORMAT_UNKNOWN, no " << sCfg.pixelFormat.toString() << " support\n";
+ return -EINVAL;
+ }
+
+ 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;
+ 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);
+
+ 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);
+ }
+ }
+}
+
+void SDLSink::writeBuffer(FrameBuffer *buffer)
+{
+ 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);
+ SDL_RenderClear(sdlRenderer_);
+ SDL_RenderCopy(sdlRenderer_, sdlTexture_, NULL, NULL);
+ 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_;
+ SDL_Window *sdlScreen_;
+ SDL_Renderer *sdlRenderer_;
+ SDL_Texture *sdlTexture_;
+ SDL_Rect sdlRect_;
+ SDL_PixelFormatEnum pf;
+};
--
2.35.1
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