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/CameraSettingsDialog.h

@@ -0,0 +1,108 @@
+/*
+    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 CAMERASETTINGSDIALOG_H
+#define CAMERASETTINGSDIALOG_H
+
+#include <QDialog>
+#include <QButtonGroup>
+
+#include "Config.h"
+#include "CameraManager.h"
+
+namespace Ui { class CameraSettingsDialog; }
+class CameraSettingsDialog;
+
+class CameraPreviewPanel : public QWidget
+{
+    Q_OBJECT
+
+public:
+    CameraPreviewPanel(QWidget* parent);
+    ~CameraPreviewPanel();
+
+    void setCurrentCam(CameraManager* cam)
+    {
+        currentCam = cam;
+    }
+
+protected:
+    void paintEvent(QPaintEvent* event) override;
+    void timerEvent(QTimerEvent* event) override
+    {
+        repaint();
+    }
+
+private:
+    int updateTimer;
+    CameraManager* currentCam;
+};
+
+class CameraSettingsDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit CameraSettingsDialog(QWidget* parent);
+    ~CameraSettingsDialog();
+
+    static CameraSettingsDialog* currentDlg;
+    static CameraSettingsDialog* openDlg(QWidget* parent)
+    {
+        if (currentDlg)
+        {
+            currentDlg->activateWindow();
+            return currentDlg;
+        }
+
+        currentDlg = new CameraSettingsDialog(parent);
+        currentDlg->open();
+        return currentDlg;
+    }
+    static void closeDlg()
+    {
+        currentDlg = nullptr;
+    }
+
+private slots:
+    void on_CameraSettingsDialog_accepted();
+    void on_CameraSettingsDialog_rejected();
+
+    void on_cbCameraSel_currentIndexChanged(int id);
+    void onChangeInputType(int type);
+    void on_txtSrcImagePath_textChanged();
+    void on_btnSrcImageBrowse_clicked();
+    void on_cbPhysicalCamera_currentIndexChanged(int id);
+    void on_chkFlipPicture_clicked();
+
+private:
+    Ui::CameraSettingsDialog* ui;
+
+    QButtonGroup* grpInputType;
+    CameraPreviewPanel* previewPanel;
+
+    int currentId;
+    Config::CameraConfig* currentCfg;
+    CameraManager* currentCam;
+
+    Config::CameraConfig oldCamSettings[2];
+
+    void populateCamControls(int id);
+};
+
+#endif // CAMERASETTINGSDIALOG_H