//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#pragma once

#include "BillboardSet.h"

/// Determines the emitter shape.
enum EmitterType
{
    EMITTER_POINT,
    EMITTER_SPHERE,
    EMITTER_BOX
};

/// One particle in the particle system.
struct Particle
{
    /// Velocity.
    Vector3 velocity_;
    /// Original billboard size.
    Vector2 size_;
    /// Time elapsed from creation.
    float timer_;
    /// Lifetime.
    float timeToLive_;
    /// Size scaling value.
    float scale_;
    /// Rotation speed.
    float rotationSpeed_;
    /// Current color fade index.
    unsigned colorIndex_;
    /// Current texture animation index.
    unsigned texIndex_;
};

/// %Texture animation definition.
struct TextureAnimation
{
    /// UV coordinates.
    Rect uv_;
    /// Time.
    float time_;
};

class ResourceCache;
class XMLFile;
class XMLElement;

/// %Particle emitter component.
class ParticleEmitter : public BillboardSet
{
    OBJECT(ParticleEmitter);
    
public:
    /// Construct.
    ParticleEmitter(Context* context);
    /// Destruct.
    virtual ~ParticleEmitter();
    /// Register object factory.
    static void RegisterObject(Context* context);
    
    /// Update before octree reinsertion. Is called from a worker thread. Needs to be requested with MarkForUpdate().
    virtual void Update(const FrameInfo& frame);
    
    /// Load emitter parameters from an XML file. Return true if successful.
    bool LoadParameters(XMLFile* file);
    /// %Set emitter active/inactive state and optionally reset active/inactive timer.
    void SetActive(bool enable, bool resetPeriod = false);
    
    /// Return parameter XML file.
    XMLFile* GetParameters() const { return parameterSource_; }
    /// Return number of particles.
    unsigned GetNumParticles() const { return particles_.Size(); }
    /// Return whether emitter is active.
    bool IsActive() const { return active_; }
    
    /// %Set parameter source attribute.
    void SetParameterSourceAttr(ResourceRef value);
    /// %Set particles attribute.
    void SetParticlesAttr(VariantVector value);
    /// Return parameter source attribute.
    ResourceRef GetParameterSourceAttr() const;
    /// Return particles attribute.
    VariantVector GetParticlesAttr() const;
    
protected:
    /// Handle node being assigned.
    virtual void OnNodeSet(Node* node);
    
    /// %Set number of particles.
    void SetNumParticles(int num);
    /// %Set color of particles.
    void SetParticleColor(const Color& color);
    /// %Set color fade of particles.
    void SetParticleColors(const Vector<ColorFade>& colors);
    /// Create a new particle. Return true if there was room.
    bool EmitNewParticle();
    /// Return a free particle index.
    unsigned GetFreeParticle() const;
    /// Read a float range from an XML element.
    void GetFloatMinMax(const XMLElement& element, float& minValue, float& maxValue);
    /// Read a Vector2 range from an XML element.
    void GetVector2MinMax(const XMLElement& element, Vector2& minValue, Vector2& maxValue);
    /// Read a Vector3 from an XML element.
    void GetVector3MinMax(const XMLElement& element, Vector3& minValue, Vector3& maxValue);
    
private:
    /// Handle scene post-update event.
    void HandleScenePostUpdate(StringHash eventType, VariantMap& eventData);
    
    /// Parameter XML file.
    SharedPtr<XMLFile> parameterSource_;
    /// Particles.
    PODVector<Particle> particles_;
    /// Color fade range.
    Vector<ColorFade> colors_;
    /// Texture animation.
    Vector<TextureAnimation> textureAnimation_;
    /// Emitter shape.
    EmitterType emitterType_;
    /// Emitter size.
    Vector3 emitterSize_;
    /// Particle direction minimum.
    Vector3 directionMin_;
    /// Particle direction maximum.
    Vector3 directionMax_;
    /// Particle constant force.
    Vector3 constanceForce_;
    /// Particle size minimum.
    Vector2 sizeMin_;
    /// Particle size maximum.
    Vector2 sizeMax_;
    /// Particle velocity damping force.
    float dampingForce_;
    /// Emitter radius if spherical.
    float emitterRadius_;
    /// Active/inactive period timer.
    float periodTimer_;
    /// New particle emission timer.
    float emissionTimer_;
    /// Active period.
    float activeTime_;
    /// Inactive period.
    float inactiveTime_;
    /// Emission interval minimum.
    float intervalMin_;
    /// Emission interval maximum.
    float intervalMax_;
    /// Particle time to live minimum.
    float timeToLiveMin_;
    /// Particle time to live maximum.
    float timeToLiveMax_;
    /// Particle velocity minimum.
    float velocityMin_;
    /// Particle velocityy maximum.
    float velocityMax_;
    /// Particle rotation angle minimum.
    float rotationMin_;
    /// Particle rotation angle maximum.
    float rotationMax_;
    /// Particle rotation speed minimum.
    float rotationSpeedMin_;
    /// Particle rotation speed maximum.
    float rotationSpeedMax_;
    /// Particle size additive parameter.
    float sizeAdd_;
    /// Particle size multiplicative parameter.
    float sizeMul_;
    /// Emitter active/inactive state.
    bool active_;
    /// Update when invisible flag.
    bool updateInvisible_;
    /// Rendering renderer framenumber on which was last updated.
    unsigned lastUpdateFrameNumber_;
};