cam: sdl_sink: Add SDL sink with initial YUYV support

This adds more portability to existing cam sinks. You can pass a
YUYV camera buffer and SDL will handle the pixel buffer conversion
to the display. 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 has not been
tested. Also tested on simpledrm Raspberry Pi 4 framebuffer
successfully where existing kms sink did not work. Can also be used as
kmsdrm sink. Only supports one camera stream at present.

Signed-off-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 194 insertions, 0 deletions

diff --git a/src/cam/sdl_sink.cpp b/src/cam/sdl_sink.cpp
new file mode 100644
index 00000000..4c74bce7
--- /dev/null
+++ b/src/cam/sdl_sink.cpp
@@ -0,0 +1,194 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2022, Ideas on Board Oy
+ *
+ * sdl_sink.h - 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"
+#include "sdl_texture_yuyv.h"
+
+using namespace libcamera;
+
+using namespace std::chrono_literals;
+
+SDLSink::SDLSink()
+	: window_(nullptr), renderer_(nullptr), rect_({}),
+	  init_(false)
+{
+}
+
+SDLSink::~SDLSink()
+{
+	stop();
+}
+
+int SDLSink::configure(const libcamera::CameraConfiguration &config)
+{
+	int ret = FrameSink::configure(config);
+	if (ret < 0)
+		return ret;
+
+	if (config.size() > 1) {
+		std::cerr
+			<< "SDL sink only supports one camera stream at present, streaming first camera stream"
+			<< std::endl;
+	} else if (config.empty()) {
+		std::cerr << "Require at least one camera stream to process"
+			  << std::endl;
+		return -EINVAL;
+	}
+
+	const libcamera::StreamConfiguration &cfg = config.at(0);
+	rect_.w = cfg.size.width;
+	rect_.h = cfg.size.height;
+
+	switch (cfg.pixelFormat) {
+	case libcamera::formats::YUYV:
+		texture_ = std::make_unique<SDLTextureYUYV>(rect_);
+		break;
+	default:
+		std::cerr << "Unsupported pixel format "
+			  << cfg.pixelFormat.toString() << 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;
+	}
+
+	init_ = true;
+	window_ = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED,
+				   SDL_WINDOWPOS_UNDEFINED, rect_.w,
+				   rect_.h,
+				   SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
+	if (!window_) {
+		std::cerr << "Failed to create SDL window: " << SDL_GetError()
+			  << std::endl;
+		return -EINVAL;
+	}
+
+	renderer_ = SDL_CreateRenderer(window_, -1, 0);
+	if (!renderer_) {
+		std::cerr << "Failed to create SDL renderer: " << SDL_GetError()
+			  << std::endl;
+		return -EINVAL;
+	}
+
+	/*
+	 * Set for scaling purposes, not critical, don't return in case of
+	 * error.
+	 */
+	ret = SDL_RenderSetLogicalSize(renderer_, rect_.w, rect_.h);
+	if (ret)
+		std::cerr << "Failed to set SDL render logical size: "
+			  << SDL_GetError() << std::endl;
+
+	ret = texture_->create(renderer_);
+	if (ret) {
+		return ret;
+	}
+
+	/* \todo Make the event cancellable to support stop/start cycles. */
+	EventLoop::instance()->addTimerEvent(
+		10ms, std::bind(&SDLSink::processSDLEvents, this));
+
+	return 0;
+}
+
+int SDLSink::stop()
+{
+	texture_.reset();
+
+	if (renderer_) {
+		SDL_DestroyRenderer(renderer_);
+		renderer_ = nullptr;
+	}
+
+	if (window_) {
+		SDL_DestroyWindow(window_);
+		window_ = nullptr;
+	}
+
+	if (init_) {
+		SDL_Quit();
+		init_ = 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();
+
+	/* \todo Implement support for multi-planar formats. */
+	const FrameMetadata::Plane &meta = buffer->metadata().planes()[0];
+
+	Span<uint8_t> data = image->data(0);
+	if (meta.bytesused > data.size())
+		std::cerr << "payload size " << meta.bytesused
+			  << " larger than plane size " << data.size()
+			  << std::endl;
+
+	texture_->update(data);
+
+	SDL_RenderClear(renderer_);
+	SDL_RenderCopy(renderer_, texture_->get(), nullptr, nullptr);
+	SDL_RenderPresent(renderer_);
+}