[libcamera-devel,v5,1/2] cam: sdl_sink: Add SDL sink

15588 diff mbox series

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/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..2b285808 100644
--- a/src/cam/main.h
+++ b/src/cam/main.h
@@ -18,6 +18,7 @@  enum {
 	OptListProperties = 'p',
 	OptMonitor = 'm',
 	OptStream = 's',
+	OptSDL = 'S',
 	OptListControls = 256,
 	OptStrictFormats = 257,
 	OptMetadata = 258,
diff --git a/src/cam/meson.build b/src/cam/meson.build
index e8e2ae57..f2249296 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..28e59cbb
--- /dev/null
+++ b/src/cam/sdl_sink.cpp
@@ -0,0 +1,198 @@ 
+/* 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()
+	: sdlWindow_(nullptr), sdlRenderer_(nullptr), sdlTexture_(nullptr), sdlRect_({}), sdlInit_(false)
+{
+}
+
+SDLSink::~SDLSink()
+{
+	stop();
+}
+
+int SDLSink::configure(const libcamera::CameraConfiguration &cfg)
+{
+	int ret = FrameSink::configure(cfg);
+	if (ret < 0)
+		return ret;
+
+	if (cfg.size() > 1) {
+		std::cerr << "SDL sink only supports one camera stream at present, streaming first camera stream"
+			  << std::endl;
+	} else if (cfg.empty()) {
+		std::cerr << "Require at least one camera stream to process" << std::endl;
+		return -EINVAL;
+	}
+
+	const libcamera::StreamConfiguration &sCfg = cfg.at(0);
+	sdlRect_.w = sCfg.size.width;
+	sdlRect_.h = sCfg.size.height;
+	switch (sCfg.pixelFormat) {
+	case libcamera::formats::YUYV:
+		pixelFormat_ = SDL_PIXELFORMAT_YUY2;
+		pitch_ = 4 * ((sdlRect_.w + 1) / 2);
+		break;
+
+	/* From here down the fourcc values are identical between SDL, drm, libcamera */
+	case libcamera::formats::NV21:
+		pixelFormat_ = SDL_PIXELFORMAT_NV21;
+		pitch_ = sdlRect_.w;
+		break;
+	case libcamera::formats::NV12:
+		pixelFormat_ = SDL_PIXELFORMAT_NV12;
+		pitch_ = sdlRect_.w;
+		break;
+	case libcamera::formats::YVU420:
+		pixelFormat_ = SDL_PIXELFORMAT_YV12;
+		pitch_ = sdlRect_.w;
+		break;
+	case libcamera::formats::YVYU:
+		pixelFormat_ = SDL_PIXELFORMAT_YVYU;
+		pitch_ = 4 * ((sdlRect_.w + 1) / 2);
+		break;
+	case libcamera::formats::UYVY:
+		pixelFormat_ = SDL_PIXELFORMAT_UYVY;
+		pitch_ = 4 * ((sdlRect_.w + 1) / 2);
+		break;
+	default:
+		std::cerr << sCfg.pixelFormat.toString() << " not present in libcamera <-> SDL map"
+			  << std::endl;
+		return -EINVAL;
+	};
+
+	return 0;
+}
+
+int SDLSink::start()
+{
+	int ret = SDL_Init(SDL_INIT_VIDEO);
+	if (ret) {
+		std::cerr << "Failed to initialize SDL: " << SDL_GetError() << std::endl;
+		return ret;
+	}
+
+	sdlInit_ = true;
+	sdlWindow_ = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, sdlRect_.w, sdlRect_.h, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
+	if (!sdlWindow_) {
+		std::cerr << "Failed to create SDL window: " << SDL_GetError() << std::endl;
+		return -EINVAL;
+	}
+
+	sdlRenderer_ = SDL_CreateRenderer(sdlWindow_, -1, 0);
+	if (!sdlRenderer_) {
+		std::cerr << "Failed to create SDL renderer: " << SDL_GetError() << std::endl;
+		return -EINVAL;
+	}
+
+	ret = SDL_RenderSetLogicalSize(sdlRenderer_, sdlRect_.w, sdlRect_.h);
+	if (ret) { /* Not critical to set, don't return in this case, set for scaling purposes */
+		std::cerr << "Failed to set SDL render logical size: " << SDL_GetError() << std::endl;
+	}
+
+	sdlTexture_ = SDL_CreateTexture(sdlRenderer_, pixelFormat_, SDL_TEXTUREACCESS_STREAMING, sdlRect_.w, sdlRect_.h);
+	if (!sdlTexture_) {
+		std::cerr << "Failed to create SDL texture: " << SDL_GetError() << std::endl;
+		return -EINVAL;
+	}
+
+	EventLoop::instance()->addEvent(-1, EventLoop::Read, std::bind(&SDLSink::processSDLEvents, this));
+
+	return 0;
+}
+
+int SDLSink::stop()
+{
+	if (sdlTexture_) {
+		SDL_DestroyTexture(sdlTexture_);
+		sdlTexture_ = nullptr;
+	}
+
+	if (sdlRenderer_) {
+		SDL_DestroyRenderer(sdlRenderer_);
+		sdlRenderer_ = nullptr;
+	}
+
+	if (sdlWindow_) {
+		SDL_DestroyWindow(sdlWindow_);
+		sdlWindow_ = nullptr;
+	}
+
+	if (sdlInit_) {
+		SDL_Quit();
+		sdlInit_ = false;
+	}
+
+	return FrameSink::stop();
+}
+
+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()) {
+		renderBuffer(buffer);
+		break; /* to be expanded to launch SDL window per 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 */
+			EventLoop::instance()->exit(0);
+		}
+	}
+}
+
+void SDLSink::renderBuffer(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(), pitch_);
+		SDL_RenderClear(sdlRenderer_);
+		SDL_RenderCopy(sdlRenderer_, sdlTexture_, nullptr, nullptr);
+		SDL_RenderPresent(sdlRenderer_);
+	}
+}
diff --git a/src/cam/sdl_sink.h b/src/cam/sdl_sink.h
new file mode 100644
index 00000000..c9b0ab8e
--- /dev/null
+++ b/src/cam/sdl_sink.h
@@ -0,0 +1,46 @@ 
+/* 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;
+	int stop() override;
+	void mapBuffer(libcamera::FrameBuffer *buffer) override;
+
+	bool processRequest(libcamera::Request *request) override;
+
+private:
+	void renderBuffer(libcamera::FrameBuffer *buffer);
+	void processSDLEvents();
+
+	std::map<libcamera::FrameBuffer *, std::unique_ptr<Image>> mappedBuffers_;
+
+	SDL_Window *sdlWindow_;
+	SDL_Renderer *sdlRenderer_;
+	SDL_Texture *sdlTexture_;
+	SDL_Rect sdlRect_;
+	SDL_PixelFormatEnum pixelFormat_;
+	bool sdlInit_;
+	int pitch_;
+};