//
//  ClampVelocityModule.cpp
//  cocos2d_libs
//
//  Created by 徐俊杰 on 2020/4/24.
//

#include "rparticle/Modules/ClampVelocityModule.h"

//#include "UnityPrefix.h"
//#include "Runtime/BaseClasses/ObjectDefines.h"
#include "rparticle/Serialize/TransferFunctions/SerializeTransfer.h"
//#include "rparticle/Modules/ClampVelocityModule.h"
#include "rparticle/ParticleSystemUtils.h"
//#include "Runtime/Misc/BuildSettings.h"

NS_RRP_BEGIN

inline float DampenOutsideLimit (float v, float limit, float dampen)
{
    float sgn = Sign (v);
    float abs = Abs (v);
    if (abs > limit)
        abs = Lerp(abs, limit, dampen);
    return abs * sgn;
}

ClampVelocityModule::ClampVelocityModule () : ParticleSystemModule(false)
,    m_SeparateAxis (false)
,    m_InWorldSpace (false)
,    m_Dampen (1.0f)
{
}

template<ParticleSystemCurveEvalMode mode>
void MagnitudeUpdateTpl(const MinMaxCurve& magnitude, const ParticleSystemReadOnlyState& roState, ParticleSystemParticles& ps, size_t fromIndex, size_t toIndex, float dampen)
{
    for (size_t q = fromIndex; q < toIndex; ++q)
    {
        float limit = Evaluate<mode> (magnitude, NormalizedTime(ps, q), GenerateRandom(ps.randomSeed[q] + kParticleSystemClampVelocityCurveId)) * roState.GetRenderScale();
        Vector3f vel = ps.velocity[q] + ps.animatedVelocity[q];
        vel = NormalizeSafe (vel) * DampenOutsideLimit (Magnitude (vel), limit, dampen);
        ps.velocity[q] = vel - ps.animatedVelocity[q];
    }
}

template<ParticleSystemCurveEvalMode mode>
void MagnitudeUpdatePerAxisTpl(const MinMaxCurve& x, const MinMaxCurve& y, const MinMaxCurve& z, const ParticleSystemReadOnlyState& roState, const ParticleSystemState& state, ParticleSystemParticles& ps, size_t fromIndex, size_t toIndex, float dampen, bool worldSpace)
{
    Matrix4x4f matrix;
    Matrix4x4f invMatrix;
    bool transform;
//    if(IS_CONTENT_NEWER_OR_SAME (kUnityVersion4_0_a1))
    if(true)
        transform = GetTransformationMatrices(matrix, invMatrix, !roState.useLocalSpace, worldSpace, state.localToWorld);
    else
        transform = false; // Revert to old broken behavior

    for (size_t q = fromIndex; q < toIndex; ++q)
    {
        Vector3f random;
        GenerateRandom3(random, ps.randomSeed[q] + kParticleSystemClampVelocityCurveId);
        float time = NormalizedTime(ps, q);

        Vector3f vel = ps.velocity[q] + ps.animatedVelocity[q];

        if (transform)
            vel = matrix * vel;

        float scale = roState.GetRenderScale();
        float limitX = Evaluate<mode>(x, time, random.x) * scale;
        float limitY = Evaluate<mode>(y, time, random.y) * scale;
        float limitZ = Evaluate<mode>(z, time, random.z) * scale;

        vel.x = DampenOutsideLimit(vel.x, limitX, dampen);
        vel.y = DampenOutsideLimit(vel.y, limitY, dampen);
        vel.z = DampenOutsideLimit(vel.z, limitZ, dampen);

        vel -= ps.animatedVelocity[q];

        if (transform)
            vel = invMatrix * vel;

        ps.velocity[q] = vel;
    }
}

template<ParticleSystemCurveEvalMode mode>
void DragUpdateTpl(const MinMaxCurve& drag, bool useParticleSize, bool useParticleVelocity, ParticleSystemParticles& ps, size_t fromIndex, size_t toIndex, float dt)
{
    int useSize = useParticleSize ? 0xffffffff : 0;
    int useVelocity = useParticleVelocity ? 0xffffffff : 0;

    for (size_t q = fromIndex; q < toIndex; ++q)
    {
        float time = NormalizedTime(ps, q);
        float random = GenerateRandom(ps.randomSeed[q] + kParticleSystemDragCurveId);
        float dragCoefficient = Evaluate<mode>(drag, time, random);

        Vector3f vel = ps.velocity[q] + ps.animatedVelocity[q];
        float velMagSqr = SqrMagnitude(vel);

        float maxDimension = ps.size[q];
//        if (ps.uses3DSize)
//        {
//            maxDimension = math::max(maxDimension, math::max(particleSizes[1].load(q), particleSizes[2].load(q)));
//        }
        maxDimension *= 0.5f;

        float circleArea = (M_PI * maxDimension * maxDimension);
        float dragValue = dragCoefficient;
        if (useSize)
            dragValue *= circleArea;
        if (useVelocity)
            dragValue *= velMagSqr;

        float velMag = sqrt(velMagSqr);
//        Vector3f normalizedVel = select(Vector3f(ZERO, ZERO, ZERO), div(vel, velMag), velMag > epsilon_normal_sqrt());
        Vector3f normalizedVel;
        if (velMag > 0)
            normalizedVel = vel / velMag;

        velMag = std::max<float>(0, velMag - dragValue * dt);
        
        vel = normalizedVel * velMag;

        ps.velocity[q] = vel - ps.animatedVelocity[q];
    }
}

void ClampVelocityModule::Update (const ParticleSystemReadOnlyState& roState, const ParticleSystemState& state, ParticleSystemParticles& ps, const size_t fromIndex, const size_t toIndex, float dt)
{
    if (m_Dampen > 0.0f)
    {
        const bool isOptimized = m_X.IsOptimized() && m_Y.IsOptimized() && m_Z.IsOptimized();

        float dampen = 1.0f - pow(1.0f - m_Dampen, dt * 30.0f);    // use a reference fps of 30, as damping is set between 0 and 1, and without the reference fps, applied damping
                                                                            // is far too small. if we don't apply dt at all, we get FogBugz case 606420, where damping is fps dependent
        if (m_SeparateAxis)
        {
            if (m_X.minMaxState == kMMCScalar)
                MagnitudeUpdatePerAxisTpl<kEMScalar>(m_X, m_Y, m_Z, roState, state, ps, fromIndex, toIndex, dampen, m_InWorldSpace);
            else if (isOptimized && m_X.UsesMinMax())
                MagnitudeUpdatePerAxisTpl<kEMOptimizedMinMax>(m_X, m_Y, m_Z, roState, state, ps, fromIndex, toIndex, dampen, m_InWorldSpace);
            else if (isOptimized)
                MagnitudeUpdatePerAxisTpl<kEMOptimized>(m_X, m_Y, m_Z, roState, state, ps, fromIndex, toIndex, dampen, m_InWorldSpace);
            else
                MagnitudeUpdatePerAxisTpl<kEMSlow>(m_X, m_Y, m_Z, roState, state, ps, fromIndex, toIndex, dampen, m_InWorldSpace);
        }
        else
        {
            if (m_Magnitude.minMaxState == kMMCScalar)
                MagnitudeUpdateTpl<kEMScalar>(m_Magnitude, roState, ps, fromIndex, toIndex, dampen);
            else if (m_Magnitude.IsOptimized() && m_Magnitude.UsesMinMax())
                MagnitudeUpdateTpl<kEMOptimizedMinMax>(m_Magnitude, roState, ps, fromIndex, toIndex, dampen);
            else if (m_Magnitude.IsOptimized())
                MagnitudeUpdateTpl<kEMOptimized>(m_Magnitude, roState, ps, fromIndex, toIndex, dampen);
            else
                MagnitudeUpdateTpl<kEMSlow>(m_Magnitude, roState, ps, fromIndex, toIndex, dampen);
        }
    }

    // apply air drag
    if (m_Drag.GetScalar() != 0.0f)
    {
        if (m_Drag.minMaxState == kMMCScalar)
            DragUpdateTpl<kEMScalar>(m_Drag, m_MultiplyDragByParticleSize, m_MultiplyDragByParticleVelocity, ps, fromIndex, toIndex, dt);
        else if (m_Drag.IsOptimized() && m_Drag.UsesMinMax())
            DragUpdateTpl<kEMOptimizedMinMax>(m_Drag, m_MultiplyDragByParticleSize, m_MultiplyDragByParticleVelocity, ps, fromIndex, toIndex, dt);
        else if (m_Drag.IsOptimized())
            DragUpdateTpl<kEMOptimized>(m_Drag, m_MultiplyDragByParticleSize, m_MultiplyDragByParticleVelocity, ps, fromIndex, toIndex, dt);
        else
            DragUpdateTpl<kEMSlow>(m_Drag, m_MultiplyDragByParticleSize, m_MultiplyDragByParticleVelocity, ps, fromIndex, toIndex, dt);
    }
}

void ClampVelocityModule::CheckConsistency ()
{
    m_Dampen = clamp<float> (m_Dampen, 0.0f, 1.0f);
    m_X.SetScalar(std::max<float> (0.0f, m_X.GetScalar()));
    m_Y.SetScalar(std::max<float> (0.0f, m_Y.GetScalar()));
    m_Z.SetScalar(std::max<float> (0.0f, m_Z.GetScalar()));
    m_Magnitude.SetScalar(std::max<float> (0.0f, m_Magnitude.GetScalar()));
    m_Drag.SetScalar(clamp<float> (m_Drag.GetScalar(), 0.0f, 100000.0f));
}

template<class TransferFunction>
void ClampVelocityModule::Transfer (TransferFunction& transfer)
{
    ParticleSystemModule::Transfer (transfer);
    transfer.Transfer (m_X, "x");
    transfer.Transfer (m_Y, "y");
    transfer.Transfer (m_Z, "z");
    transfer.Transfer (m_Magnitude, "magnitude");
    transfer.Transfer (m_SeparateAxis, "separateAxis");
    transfer.Transfer (m_InWorldSpace, "inWorldSpace");
    transfer.Transfer (m_MultiplyDragByParticleSize, "multiplyDragByParticleSize");
    transfer.Transfer (m_MultiplyDragByParticleVelocity, "multiplyDragByParticleVelocity"); transfer.Align ();
    transfer.Transfer (m_Dampen, "dampen");
    transfer.Transfer (m_Drag, "drag");
}
INSTANTIATE_TEMPLATE_TRANSFER(ClampVelocityModule)

NS_RRP_END