Compositor.h

#pragma once

#include <Lemon/Graphics/Surface.h>
#include <Lemon/Graphics/Types.h>

#include <atomic>
#include <ctime>
#include <list>
#include <thread>

template <typename T, class... D> std::list<T> SplitModify(Rect& victim, const Rect& cut, D... extraData) {
    std::list<T> clips;

    if (cut.left() > victim.left() && cut.left() <= victim.right()) { // Clip left edge
        Rect clip;
        clip.top(victim.top());
        clip.left(victim.left());
        clip.bottom(victim.bottom());
        clip.right(cut.left() - 1); // Left of cutting rect's left edge

        victim.left(cut.left());

        if (clip.width > 0) {
            clips.push_back(T{clip, extraData...});
        }
    }

    if (cut.top() > victim.top() && cut.top() <= victim.bottom()) { // Clip top edge
        Rect clip;
        clip.top(victim.top());
        clip.left(victim.left());
        clip.bottom(cut.top() - 1); // Above cutting rect's top edge
        clip.right(victim.right());

        victim.top(cut.top());

        if (clip.height > 0) {
            clips.push_back(T{clip, extraData...});
        }
    }

    if (cut.right() >= victim.left() && cut.right() < victim.right()) { // Clip right edge
        Rect clip;
        clip.top(victim.top());
        clip.left(cut.right() + 1);
        clip.bottom(victim.bottom());
        clip.right(victim.right());

        victim.right(cut.right());

        if (clip.width > 0) {
            clips.push_back(T{clip, extraData...});
        }
    }

    if (cut.bottom() >= victim.top() && cut.bottom() < victim.bottom()) { // Clip bottom edge
        Rect clip;
        clip.top(cut.bottom() + 1);
        clip.left(victim.left());
        clip.bottom(victim.bottom());
        clip.right(victim.right());

        victim.bottom(cut.bottom());

        if (clip.height > 0) {
            clips.push_back(T{clip, extraData...});
        }
    }

    return clips;
}

template <typename T, class... D> inline std::list<T> Split(Rect victim, const Rect& cut, D... extraData){
    return SplitModify<T, D...>(victim, cut, extraData...);
}

struct WindowClipRect {
    Rect rect;
    class WMWindow* win;
    enum {
        TypeWindow,
        TypeWindowDecoration,
    } type = TypeWindow;
    bool invalid = true;
    bool occluded = false;

    std::list<WindowClipRect> SplitModify(const Rect& cut) { return ::SplitModify<WindowClipRect>(rect, cut, win, type, true, occluded); }
    std::list<WindowClipRect> Split(const Rect& cut) { return ::Split<WindowClipRect>(rect, cut, win, type, true, occluded); }
};

struct BackgroundClipRect {
    Rect rect;
    bool invalid = true;

    std::list<BackgroundClipRect> SplitModify(const Rect& cut) { return ::SplitModify<BackgroundClipRect, bool>(rect, cut, true); }
    std::list<BackgroundClipRect> Split(const Rect& cut) { return ::Split<BackgroundClipRect, bool>(rect, cut, true); }
};

class Compositor {
public:
    Compositor(const Surface& displaySurface);

    void Render();

    inline Vector2i GetScreenBounds() const { return {m_renderSurface.width, m_renderSurface.height}; }

    void InvalidateAll();
    void Invalidate(const Rect& rect);
    void InvalidateWindow(class WMWindow* window);

    void SetWallpaper(const std::string& path);
    void SetShouldDisplayFramerate(bool value) { m_displayFramerate = value; }

    inline void SetNormalCursor() { m_cursorCurrent = &m_cursorNormal; }
    inline void SetResizeCursor() { m_cursorCurrent = &m_cursorResize; }

private:
    void RecalculateWindowClipping();
    void RecalculateBackgroundClipping();
    void RecalculateRenderClipping();

    void InvalidateBackgroundRect(BackgroundClipRect& bgRect);
    void InvalidateWindowRect(WindowClipRect& wRect);
    void InvalidateDecorationRect(WindowClipRect& dRect);

    bool m_invalidateAll = true;
    bool m_displayFramerate = false;

    Vector2i m_lastMousePos = {0, 0};
    Surface m_cursorNormal; // Normal mouse cursor
    Surface m_cursorResize; // Window resize mouse cursor
    Surface* m_cursorCurrent = &m_cursorNormal; // Current mouse cursor

    // Used for framerate counter
    timespec m_lastRender;
    long m_avgFrametime = 0;
    long m_fCount = 0;
    int m_fRate = 0;

    Surface m_renderSurface;  // Backbuffer to render to
    Surface m_displaySurface; // Display mapped surface

    Surface m_wallpaper = {}; // Wallpaper surface
    std::thread m_wallpaperThread;
    std::atomic<int> m_wallpaperStatus = 0;
    std::mutex m_renderMutex; // Currently only used for the wallpaper for invalidation
    std::mutex m_wallpaperMutex;

    std::list<BackgroundClipRect> m_backgroundRects;
    std::list<WindowClipRect> m_windowClipRects;
    // Clip rects used when determining which parts of the screen
    // to copy to the framebuffer
    std::list<BackgroundClipRect> m_renderClipRects;
};