lol/src/engine/entity.h

//
//  Lol Engine
//
//  Copyright © 2010—2018 Sam Hocevar <sam@hocevar.net>
//
//  Lol Engine is free software. It comes without any warranty, to
//  the extent permitted by applicable law. You can redistribute it
//  and/or modify it under the terms of the Do What the Fuck You Want
//  to Public License, Version 2, as published by the WTFPL Task Force.
//  See http://www.wtfpl.net/ for more details.
//

#pragma once

//
// The Entity class
// ----------------
// Entities are objects that can be ticked by the game loop and/or the render
// loop. Entities are implemented as one or several linked lists. See the
// Ticker class for the ticking logic and the linked list implementation.
//

#include <stdint.h>

namespace lol
{

struct InitState
{
    enum Value
    {
        Unknown,
        Error,
        NeedInitDraw,
        NeedInitGame,
        Ready,
    }
    m_value;

    inline InitState(Value v) : m_value(v) {}
    inline operator Value() { return m_value; }
};

class Entity
{
    friend class Scene;
    friend class Ticker;
    friend class TickerData;
    friend class Dict;
    friend class Emcee;

public:
    virtual std::string GetName() const;

    inline bool IsTicked() { return !!m_ref && !m_autorelease; }
protected:
    Entity();
    virtual ~Entity();

    inline int  IsDestroying() { return m_destroy; }

    virtual void InitGame();
    virtual void InitDraw();

    virtual void tick_game(float seconds);
    virtual void tick_draw(float seconds, class Scene &scene);

    enum
    {
        GAMEGROUP_BEGIN = 0, // must be the first element

        GAMEGROUP_INPUT,     // input should be polled before everything else
        GAMEGROUP_IMGUI,     // debug update needs to be called before the rest for init purposes
        GAMEGROUP_APP,       // main application update
        GAMEGROUP_ENTITY,    // default entity update
        // ----------------- // split entity update:
        GAMEGROUP_PLAYER,    // player updates before AI to ensure player actions is prevalent
        GAMEGROUP_AI,        // AI update
        GAMEGROUP_OTHER_0,   // other misc updates here
        GAMEGROUP_OTHER_1,   //  (same)
        GAMEGROUP_OTHER_2,   //  (same)
        GAMEGROUP_OTHER_3,   //  (same)
        // ----------------- // primitives updates
        GAMEGROUP_MESH,      // update Mesh/Animation to ensure correct sync with PLY/AI
        GAMEGROUP_FX,        // update FX/other to ensure correct sync with WorldPos and Meshes
        GAMEGROUP_LIGHT,     // update after FX because it could some
        GAMEGROUP_CAMERA,    // update camera at the end of the frame, once everything is settled
        GAMEGROUP_STATS,     // stats update

        GAMEGROUP_END        // must be the last element
    }
    m_gamegroup;

    enum
    {
        DRAWGROUP_BEGIN = GAMEGROUP_END,

        DRAWGROUP_CAMERA,   // update camera first for rendering
        DRAWGROUP_TEXTURE,  // texture
        DRAWGROUP_LIGHT,    //
        DRAWGROUP_WORLD,    // other misc updates here
        DRAWGROUP_ENTITY,   //
        DRAWGROUP_FX,       //
        DRAWGROUP_OTHER_0,  // other misc updates here
        DRAWGROUP_OTHER_1,  //  (same)
        DRAWGROUP_OTHER_2,  //  (same)
        DRAWGROUP_OTHER_3,  //  (same)
        DRAWGROUP_APP,      // main application Draw
        DRAWGROUP_HUD,
        DRAWGROUP_IMGUI,
        DRAWGROUP_CAPTURE,

        DRAWGROUP_END,      // must be the next-to-last element
        DRAWGROUP_NONE,     // this group is for non draw-ticked
    }
    m_drawgroup;

    static int const ALLGROUP_END = DRAWGROUP_END;

    /* The initialisation state */
    InitState m_initstate;

#if !LOL_BUILD_RELEASE
    enum
    {
        STATE_IDLE = 0,
        STATE_PRETICK_GAME,
        STATE_POSTTICK_GAME,
        STATE_PRETICK_DRAW,
        STATE_POSTTICK_DRAW,
    }
    m_tickstate;
#endif

    // Emcee begin
private:
    void SetState(uint32_t newstate);
    void SetStateWhenMatch(uint32_t newstate,
                           Entity *other_entity, uint32_t other_state);
    virtual uint32_t OnStateChanged(uint32_t newstate)
    {
        return LOLm_state = newstate;
    }

    uint32_t LOLm_state;
    // Emcee end

private:
    int m_ref, m_autorelease, m_destroy;
    uint64_t m_scene_mask = 0;
};

} /* namespace lol */