/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

This program 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.

This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
NVIDIA PhysX SDK, Microsoft DirectX SDK, OpenSSL library, Independent
JPEG Group JPEG library, Microsoft Windows Media SDK, or Apple QuickTime SDK
(or a modified version of those libraries),
containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
PhysX SDK EULA, DirectX SDK EULA, OpenSSL and SSLeay licenses, IJG
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licensors of this Program grant you additional
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 or by snail mail at:
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*==LICENSE==*/
#ifndef plParticleSystem_inc
#define plParticleSystem_inc

#include "hsTemplates.h"
#include "hsGeometry3.h"
#include "pnModifier/plModifier.h"
#include "pnNetCommon/plSynchedValue.h"
#include "hsColorRGBA.h"
#include "hsMatrix44.h"
#include "plEffectTargetInfo.h"

class plPipeline;
class plParticle;
class plParticleGenerator;
class plSimpleParticleGenerator;
class plParticleEmitter;
class plParticleEffect;
class plParticleSDLMod;
class plController;
class hsGMaterial;
class plDrawableSpans;
class plDrawInterface;
class Mtl;

// This is responsible for creating and maintaining (allocation and update cycle) a related set of particles. 
// Automatic particle generation is handled by the plParticleEmitters (one for each spawning location).

class plParticleSystem : public plModifier
{
    friend class plParticleEmitter;
    friend class plSimpleParticleGenerator;

protected:
    static const hsScalar GRAVITY_ACCEL_FEET_PER_SEC2;
    plSceneObject *fTarget;

    hsGMaterial *fTexture;          // One texture per system (Tiling is your friend!)  
    UInt32 fXTiles, fYTiles;        // Width/height of the texture (in tiles) for determining a particle's UVs

    double fCurrTime;
    double fLastTime;
    hsVector3 fAccel;
    hsScalar fPreSim;
    hsScalar fDrag;
    hsScalar fWindMult;
    bool    fAttachedToAvatar;

    UInt32 fMaxTotalParticles;
    UInt32 fMaxTotalParticlesLeft;
    UInt32 fNumValidEmitters;
    UInt32 fMaxEmitters;
    UInt32 fNextEmitterToGo;

    plParticleEmitter **fEmitters;  // Various locations we're emitting particles from (the first one is
                                    // reserved for particles added explicitly (to keep all the bookkeeping
                                    // in the hands of plParticleEmitter).
    
    hsTArray<plParticleEffect *> fForces;       // Global forces (wind/gravity/etc) that affect accelleration.
    hsTArray<plParticleEffect *> fEffects;      // Any other non-constraint effects.
    hsTArray<plParticleEffect *> fConstraints;  // Rigid body, collision, connectivity, etc.
    plParticleContext   fContext; // Rendering context passed to forces/effects/constraints.

    hsTArray<plKey>     fPermaLights; // Runtime lights assigned to this system. Currently don't support projected lights on particles.

    // Material related animations, mapped over the course of a particle's life
    plController *fAmbientCtl;
    plController *fDiffuseCtl;
    plController *fOpacityCtl;  
    plController *fWidthCtl;
    plController *fHeightCtl;

    plParticleSDLMod *fParticleSDLMod;

    hsBool IShouldUpdate(plPipeline* pipe) const;
    virtual hsBool IEval(double secs, hsScalar del, UInt32 dirty); // required by plModifier
    void IHandleRenderMsg(plPipeline* pipe);
    plDrawInterface* ICheckDrawInterface();
    void IAddEffect(plParticleEffect *effect, UInt32 type);
    void IReadEffectsArray(hsTArray<plParticleEffect *> &effects, UInt32 type, hsStream *s, hsResMgr *mgr);
    void IPreSim();

public:
    plParticleSystem();
    virtual ~plParticleSystem();
    void Init(UInt32 xTiles, UInt32 yTiles, UInt32 maxTotalParticles, UInt32 numEmitters, 
              plController *ambientCtl, plController *diffuseCtl, plController *opacityCtl, 
              plController *widthCtl, plController *heightCtl);

    enum effectType
    {
        kEffectForce = 0x1,
        kEffectMisc = 0x2,
        kEffectConstraint = 0x4,
    };
    
    enum miscFlags
    {
        kParticleSystemAlwaysUpdate = 0x1
    };
    UInt8 fMiscFlags; // Not read/written (could be, but it's not needed yet.)
    
    // There might not be enough particles available. this function returns the number of maxParticles that
    // the emitter actually received.
    UInt32 AddEmitter(UInt32 maxParticles, plParticleGenerator *gen, UInt32 emitterFlags);

    plParticleEmitter* GetAvailEmitter();
    
    CLASSNAME_REGISTER( plParticleSystem );
    GETINTERFACE_ANY( plParticleSystem, plModifier);
    
    // These are just public wrappers to the equivalent plParticleEmitter functions, provided for the purpose
    // of adding particles to a system explicitly.
    void AddParticle(hsPoint3 &pos, hsVector3 &velocity, UInt32 tileIndex, 
        hsScalar hSize, hsScalar vSize, hsScalar scale, hsScalar invMass, hsScalar life, 
        hsPoint3 &orientation, UInt32 miscFlags, hsScalar radsPerSec=0.f);
    void GenerateParticles(UInt32 num, hsScalar dt = 0.f);
    void WipeExistingParticles(); // Instant nuke
    void KillParticles(hsScalar num, hsScalar timeToDie, UInt8 flags); // Sets a death timer. They'll get removed on the next update (if time has run out)
    UInt16 StealParticlesFrom(plParticleSystem *victim, UInt16 num); // Returns the number of particles actually stolen     
    void TranslateAllParticles(hsPoint3 &amount); // Used to recenter the system when linking between ages. 
    
    void DisableGenerators();
    UInt32 GetNumTiles() const { return fXTiles * fYTiles; }
    void SetTileIndex(plParticle &particle, UInt32 index); // Sets the UV coordinates appropriate for the current texture
    UInt32 GetNumValidParticles(hsBool immortalOnly = false) const; // Takes a bit longer if we want a count of immortal particles...
    UInt32 GetMaxTotalParticles() const { return fMaxTotalParticles; }
    
    const hsMatrix44 &GetLocalToWorld() const;
    void SetAccel(const hsVector3& a) { fAccel = GRAVITY_ACCEL_FEET_PER_SEC2 * a; }
    void SetGravity(hsScalar pct) { fAccel.Set(0, 0, -GRAVITY_ACCEL_FEET_PER_SEC2 * pct); }
    void SetDrag(hsScalar d) { fDrag = -d; }
    void SetWindMult(hsScalar m) { fWindMult = m; }
    void SetPreSim(hsScalar time) { fPreSim = time; }
    void UpdateGenerator(UInt32 paramID, hsScalar value);
    plParticleGenerator *GetExportedGenerator() const;
    
    const hsVector3& GetAccel() const { return fAccel; }
    hsScalar GetDrag() const { return fDrag; }
    hsScalar GetWindMult() const { return fWindMult; }
    plParticleEffect *GetEffect(UInt16 type) const;
    
    plParticleSDLMod* GetSDLMod() {return fParticleSDLMod;}
    // Functions related to/required by plModifier
    virtual int GetNumTargets() const { return fTarget ? 1 : 0; }
    virtual plSceneObject* GetTarget(int w) const { hsAssert(w < 1, "Bad target"); return fTarget; }
    virtual void AddTarget(plSceneObject* so);
    virtual void RemoveTarget(plSceneObject* so);
    
    virtual void Read(hsStream* s, hsResMgr* mgr); 
    virtual void Write(hsStream* s, hsResMgr* mgr);
    virtual hsBool MsgReceive(plMessage* msg);
    
    void SetAttachedToAvatar(bool attached);
    
    // Export only functions for building the system. Not supported at runtime.
    // AddLight allows the particle system to remain in ignorant bliss about runtime lights
    void AddLight(plKey liKey);
};

#endif