framestream2 (with rigtorp/SPSCQueue)

src/content/stream_reader_sdl_video.cpp

@@ -0,0 +1,84 @@
+#include "./stream_reader_sdl_video.hpp"
+
+#include <iostream>
+
+SDLVideoFrameStreamReader::SDLVideoFrameStreamReader() : _camera{nullptr, &SDL_CloseCamera}, _surface{nullptr, &SDL_DestroySurface} {
+	// enumerate
+	int devcount = 0;
+	SDL_CameraDeviceID *devices = SDL_GetCameraDevices(&devcount);
+
+	if (devices == nullptr || devcount < 1) {
+		throw int(1); // TODO: proper exception?
+	}
+
+	std::cout << "### found cameras:\n";
+	for (int i = 0; i < devcount; i++) {
+		const SDL_CameraDeviceID device = devices[i];
+		char *name = SDL_GetCameraDeviceName(device);
+
+		std::cout << "  - Camera #" << i << ": " << name << "\n";
+
+		SDL_free(name);
+	}
+
+	_camera = {
+		SDL_OpenCameraDevice(devices[0], nullptr),
+		&SDL_CloseCamera
+	};
+	if (!static_cast<bool>(_camera)) {
+		throw int(2);
+	}
+
+	SDL_CameraSpec spec;
+	if (SDL_GetCameraFormat(_camera.get(), &spec) < 0) {
+		// meh
+	} else {
+		// interval
+		float interval = float(spec.interval_numerator)/float(spec.interval_denominator);
+		std::cout << "camera interval: " << interval*1000 << "ms\n";
+	}
+}
+
+SDLVideoFrameStreamReader::VideoFrame SDLVideoFrameStreamReader::getNextVideoFrameRGBA(void) {
+	if (!static_cast<bool>(_camera)) {
+		return {};
+	}
+
+	Uint64 timestampNS = 0;
+	SDL_Surface* frame_next = SDL_AcquireCameraFrame(_camera.get(), &timestampNS);
+
+	// no new frame yet, or error
+	if (frame_next == nullptr) {
+		//std::cout << "failed acquiring frame\n";
+		return {};
+	}
+
+	// TODO: investigate zero copy
+	_surface = {
+		SDL_ConvertSurfaceFormat(frame_next, SDL_PIXELFORMAT_RGBA8888),
+		&SDL_DestroySurface
+	};
+
+	SDL_ReleaseCameraFrame(_camera.get(), frame_next);
+
+	SDL_LockSurface(_surface.get());
+
+	return {
+		_surface->w,
+		_surface->h,
+		timestampNS,
+		{
+			reinterpret_cast<const uint8_t*>(_surface->pixels),
+			uint64_t(_surface->w*_surface->h*4) // rgba
+		}
+	};
+}
+
+int64_t SDLVideoFrameStreamReader::have(void) {
+	return -1;
+}
+
+ByteSpan SDLVideoFrameStreamReader::getNext(void) {
+	return {};
+}
+