VideoMode.h

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/* Copyright (C) 2023 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_VIDEOMODE
#define INCLUDED_VIDEOMODE

#include "ps/CStrForward.h"
#include "renderer/backend/Backend.h"

#include <memory>

typedef struct SDL_Window SDL_Window;

namespace Renderer
{
namespace Backend
{
class IDevice;
}
}

class CVideoMode
{
public:
    CVideoMode();
    ~CVideoMode();

    /**
     * Initialise the video mode, for use in an SDL-using application.
     */
    bool InitSDL();

    /**
     * Initialise parts of the video mode, for use in Atlas (which uses
     * wxWidgets instead of SDL for GL).
     */
    bool InitNonSDL();

    /**
     * Shut down after InitSDL/InitNonSDL, so that they can be used again.
     */
    void Shutdown();

    /**
     * Creates a backend device. Also we use wxWidgets in Atlas so we don't need
     * to create one for that case.
     */
    bool CreateBackendDevice(const bool createSDLContext);

    /**
     * Resize the SDL window and associated graphics stuff to the new size.
     */
    bool ResizeWindow(int w, int h);

    /**
     * Set scale and tell dependent compoenent to recompute sizes.
     */
    void Rescale(float scale);

    /**
     * Switch to fullscreen or windowed mode.
     */
    bool SetFullscreen(bool fullscreen);

    /**
    * Returns true if window runs in fullscreen mode.
    */
    bool IsInFullscreen() const;

    /**
     * Switch between fullscreen and windowed mode.
     */
    bool ToggleFullscreen();

    /**
     * Update window position, to restore later if necessary (SDL2 only).
     */
    void UpdatePosition(int x, int y);

    /**
     * Update the graphics code to start drawing to the new size.
     * This should be called after the GL context has been resized.
     * This can also be used when the GL context is managed externally, not via SDL.
     */
    static void UpdateRenderer(int w, int h);

    int GetXRes() const;
    int GetYRes() const;
    int GetBPP() const;

    bool IsVSyncEnabled() const;

    int GetDesktopXRes() const;
    int GetDesktopYRes() const;
    int GetDesktopBPP() const;
    int GetDesktopFreq() const;

    float GetScale() const;

    SDL_Window* GetWindow();

    void SetWindowIcon();

    void SetCursor(const CStrW& name);
    void ResetCursor();

    Renderer::Backend::IDevice* GetBackendDevice() { return m_BackendDevice.get(); }

private:
    void ReadConfig();
    int GetBestBPP();
    bool SetVideoMode(int w, int h, int bpp, bool fullscreen);

    bool TryCreateBackendDevice(SDL_Window* window);
    void DowngradeBackendSettingAfterCreationFailure();

    /**
     * Remember whether Init has been called. (This isn't used for anything
     * important, just for verifying that the callers call our methods in
     * the right order.)
     */
    bool m_IsInitialised = false;

    SDL_Window* m_Window = nullptr;

    // Initial desktop settings.
    // Frequency is in Hz, and BPP means bits per pixels (not bytes per pixels).
    int m_PreferredW = 0;
    int m_PreferredH = 0;
    int m_PreferredBPP = 0;
    int m_PreferredFreq = 0;

    float m_Scale = 1.0f;

    // Config file settings (0 if unspecified)
    int m_ConfigW = 0;
    int m_ConfigH = 0;
    int m_ConfigBPP = 0;
    int m_ConfigDisplay = 0;
    bool m_ConfigEnableHiDPI = false;
    bool m_ConfigVSync = false;

    // (m_ConfigFullscreen defaults to false, so users don't get stuck if
    // e.g. half the filesystem is missing and the config files aren't loaded).
    bool m_ConfigFullscreen = false;

    // If we're fullscreen, size/position of window when we were last windowed (or the default window
    // size/position if we started fullscreen), to support switching back to the old window size/position
    int m_WindowedW;
    int m_WindowedH;
    int m_WindowedX;
    int m_WindowedY;

    // Whether we're currently being displayed fullscreen
    bool m_IsFullscreen = false;

    // The last mode selected
    int m_CurrentW;
    int m_CurrentH;
    int m_CurrentBPP;

    class CCursor;
    std::unique_ptr<CCursor> m_Cursor;

    Renderer::Backend::Backend m_Backend = Renderer::Backend::Backend::GL;
    std::unique_ptr<Renderer::Backend::IDevice> m_BackendDevice;
};

extern CVideoMode g_VideoMode;

#endif // INCLUDED_VIDEOMODE