82 lines
2.1 KiB
C++
82 lines
2.1 KiB
C++
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#include "./sdl_video_frame_stream2.hpp"
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#include <chrono>
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#include <cstdint>
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#include <iostream>
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#include <memory>
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#include <thread>
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SDLVideoCameraContent::SDLVideoCameraContent(void) {
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int devcount = 0;
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SDL_CameraDeviceID *devices = SDL_GetCameraDevices(&devcount);
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if (devices == nullptr || devcount < 1) {
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throw int(1); // TODO: proper exception?
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}
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std::cout << "### found cameras:\n";
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for (int i = 0; i < devcount; i++) {
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const SDL_CameraDeviceID device = devices[i];
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char *name = SDL_GetCameraDeviceName(device);
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std::cout << " - Camera #" << i << ": " << name << "\n";
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SDL_free(name);
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}
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_camera = {
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SDL_OpenCameraDevice(devices[0], nullptr),
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&SDL_CloseCamera
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};
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if (!static_cast<bool>(_camera)) {
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throw int(2);
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}
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SDL_CameraSpec spec;
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float interval {0.1f};
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if (SDL_GetCameraFormat(_camera.get(), &spec) < 0) {
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// meh
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} else {
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// interval
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interval = float(spec.interval_numerator)/float(spec.interval_denominator);
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std::cout << "camera interval: " << interval*1000 << "ms\n";
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}
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_thread = std::thread([this, interval](void) {
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while (!_thread_should_quit) {
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Uint64 timestampNS = 0;
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SDL_Surface* sdl_frame_next = SDL_AcquireCameraFrame(_camera.get(), ×tampNS);
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// no new frame yet, or error
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if (sdl_frame_next == nullptr) {
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// only sleep 1/10, we expected a frame
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std::this_thread::sleep_for(std::chrono::milliseconds(int64_t(interval*1000 / 10)));
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continue;
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}
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SDLVideoFrame new_frame {
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timestampNS,
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sdl_frame_next
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};
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bool someone_listening = pushValue(new_frame);
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SDL_ReleaseCameraFrame(_camera.get(), sdl_frame_next);
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if (someone_listening) {
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// TODO: maybe double the freq?
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std::this_thread::sleep_for(std::chrono::milliseconds(int64_t(interval*1000)));
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} else {
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// we just sleep 4x as long, bc no one is listening
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std::this_thread::sleep_for(std::chrono::milliseconds(int64_t(interval*1000*4)));
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}
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}
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});
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}
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SDLVideoCameraContent::~SDLVideoCameraContent(void) {
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_thread_should_quit = true;
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_thread.join();
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// TODO: what to do if readers are still present?
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}
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