actual DSi camera support (#1520)

basically feeding something that isn't a fixed stripe pattern, and emulating enough of the camera hardware to make this work

src/frontend/qt_sdl/CameraManager.h

@@ -0,0 +1,133 @@
+/*
+    Copyright 2016-2022 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef CAMERAMANAGER_H
+#define CAMERAMANAGER_H
+
+#include <QCamera>
+#if QT_VERSION >= 0x060000
+    #include <QMediaDevices>
+    #include <QCameraDevice>
+    #include <QMediaCaptureSession>
+    #include <QVideoSink>
+#else
+    #include <QCameraInfo>
+    #include <QAbstractVideoSurface>
+    #include <QVideoSurfaceFormat>
+#endif
+#include <QMutex>
+
+#include "types.h"
+
+class CameraManager;
+
+
+#if QT_VERSION >= 0x060000
+
+class CameraFrameDumper : public QVideoSink
+{
+    Q_OBJECT
+
+public:
+    CameraFrameDumper(QObject* parent = nullptr);
+
+public slots:
+    void present(const QVideoFrame& frame);
+
+private:
+    CameraManager* cam;
+};
+
+#else
+
+class CameraFrameDumper : public QAbstractVideoSurface
+{
+    Q_OBJECT
+
+public:
+    CameraFrameDumper(QObject* parent = nullptr);
+
+    bool present(const QVideoFrame& frame) override;
+    QList<QVideoFrame::PixelFormat> supportedPixelFormats(QAbstractVideoBuffer::HandleType type = QAbstractVideoBuffer::NoHandle) const override;
+
+private:
+    CameraManager* cam;
+};
+
+#endif
+
+
+class CameraManager : public QObject
+{
+    Q_OBJECT
+
+public:
+    CameraManager(int num, int width, int height, bool yuv);
+    ~CameraManager();
+
+    void init();
+    void deInit();
+
+    void start();
+    void stop();
+    bool isStarted();
+
+    void setXFlip(bool flip);
+
+    void captureFrame(u32* frame, int width, int height, bool yuv);
+
+    void feedFrame(u32* frame, int width, int height, bool yuv);
+    void feedFrame_NV12(u8* planeY, u8* planeUV, int width, int height);
+
+signals:
+    void camStartSignal();
+    void camStopSignal();
+
+private slots:
+    void camStart();
+    void camStop();
+
+private:
+    int num;
+
+    int startNum;
+
+    int inputType;
+    QString imagePath;
+    QString camDeviceName;
+
+    QCamera* camDevice;
+    CameraFrameDumper* camDumper;
+#if QT_VERSION >= 0x060000
+    QMediaCaptureSession* camSession;
+#endif
+
+    int frameWidth, frameHeight;
+    bool frameFormatYUV;
+    u32* frameBuffer;
+    u32* tempFrameBuffer;
+    QMutex frameMutex;
+
+    bool xFlip;
+
+    void copyFrame_Straight(u32* src, int swidth, int sheight, u32* dst, int dwidth, int dheight, bool xflip, bool yuv);
+    void copyFrame_RGBtoYUV(u32* src, int swidth, int sheight, u32* dst, int dwidth, int dheight, bool xflip);
+    void copyFrame_YUVtoRGB(u32* src, int swidth, int sheight, u32* dst, int dwidth, int dheight, bool xflip);
+};
+
+#endif // CAMERAMANAGER_H