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

#include "rparticle/ParticleSystemUtils.h"
#include "rparticle/Modules/ParticleSystemModule.h"
#include "rparticle/ParticleSystemParticle.h"
#include "rparticle/Modules/ColorModule.h"
#include "rparticle/Modules/ColorByVelocityModule.h"
#include "rparticle/Modules/SizeModule.h"
#include "rparticle/Modules/SizeByVelocityModule.h"
#include "rparticle/Modules/SubEmitterModule.h"

NS_RRP_BEGIN

UInt32 randomSeed = 0x1337;

UInt32 GetGlobalRandomSeed ()
{
    return ++randomSeed;
}

void ResetGlobalRandomSeed ()
{
    randomSeed = 0x1337;
}

Vector2f CalculateInverseLerpOffsetScale (const Vector2f& range)
{
    Assert (range.x < range.y);
    float scale = 1.0F / (range.y - range.x);
    return Vector2f (scale, -range.x * scale);
}

void CalculatePositionAndVelocity(Vector3f& initialPosition, Vector3f& initialVelocity, const ParticleSystemReadOnlyState& roState, const ParticleSystemState& state, const ParticleSystemParticles& ps, const size_t index)
{
    initialPosition = ps.position[index];
    initialVelocity = ps.velocity[index] + ps.animatedVelocity[index];
    if(roState.useLocalSpace)
    {
        // If we are in local space, transform to world space to make independent of this emitters transform
//        initialPosition = state.localToWorld.MultiplyPoint3(initialPosition);
//        initialVelocity = state.localToWorld.MultiplyVector3(initialVelocity);
        state.localToWorld.transformPoint(&initialPosition);
        state.localToWorld.transformVector(&initialVelocity);
    }
}

static void CalculateInheritedProperties(const ParticleSystemReadOnlyState& roState, SubEmitterInheritValues& initialProperties, int properties, const ParticleSystemParticle& particle, RParticleSystem* srcSystem, float normalizedT)
{
    if (properties & SubEmitterModule::kInheritColor)
    {
        initialProperties.color = particle.color;

        if (srcSystem->GetColorModule()->GetEnabled())
            srcSystem->GetColorModule()->UpdateSingle(particle, initialProperties.color);
        if (srcSystem->GetColorBySpeedModule()->GetEnabled())
            srcSystem->GetColorBySpeedModule()->UpdateSingle(roState, particle, initialProperties.color);
    }
    if (properties & SubEmitterModule::kInheritSize)
    {
        initialProperties.size = particle.size;

        if (srcSystem->GetSizeModule()->GetEnabled())
            srcSystem->GetSizeModule()->UpdateSingle(particle, true, initialProperties.size);
        if (srcSystem->GetSizeBySpeedModule()->GetEnabled())
            srcSystem->GetSizeBySpeedModule()->UpdateSingle(roState, particle, true, initialProperties.size);
    }
    if (properties & SubEmitterModule::kInheritRotation)
    {
        initialProperties.rotation = particle.rotation;
        initialProperties.axisOfRotation = particle.axisOfRotation;
    }
    if (properties & SubEmitterModule::kInheritLifetime)
    {
        initialProperties.lifetimeMultiplier = particle.lifetime;
    }
    if (properties & SubEmitterModule::kInheritDuration)
    {
        initialProperties.normalizedT = normalizedT;
    }
}

void KillParticle(const ParticleSystemReadOnlyState& roState, ParticleSystemState& state, ParticleSystemParticles& ps, size_t index, size_t& particleCount)
{
    Assert(particleCount > 0);
    
    for(int i = 0; i < state.numCachedSubDataDeath; i++)
    {
        ParticleSystemEmissionState emissionState;
        RecordEmit(emissionState, state.cachedSubDataDeath[i], roState, state, ps, kParticleSystemSubTypeDeath, i, index, 0.0f, 0.0001f, 1.0f);
    }
    
    ps.element_assign (index, particleCount - 1);
    --particleCount;
    
}

void RecordEmit(ParticleSystemEmissionState& emissionState, const ParticleSystemSubEmitterData& subEmitterData, const ParticleSystemReadOnlyState& roState, ParticleSystemState& state, ParticleSystemParticles& ps, ParticleSystemSubType type, int subEmitterIndex, size_t particleIndex, float t, float dt, float length)
{
    size_t numContinuous = 0;
    Vector3f initialPosition;
    Vector3f initialVelocity;
    CalculatePositionAndVelocity(initialPosition, initialVelocity, roState, state, ps, particleIndex);
    int amountOfParticlesToEmit = RParticleSystem::EmitFromData (roState, emissionState, numContinuous, subEmitterData.emissionData, initialVelocity, t, std::min(t + dt, length), dt, length);
    if(amountOfParticlesToEmit)
    {
        SubEmitterInheritValues inheritValues;
        auto subEmitterProperties = subEmitterData.properties;
        if (subEmitterProperties)
        {
            ParticleSystemParticle particle;
            //particle.position = ps.position[particleIndex];
            //particle.velocity = ps.velocity[particleIndex];
            //particle.animatedVelocity = ps.animatedVelocity[particleIndex];
            particle.color = ps.color[particleIndex];
            particle.size = ps.size[particleIndex] / roState.GetRenderScale();
            particle.startLifetime = ps.startLifetime[particleIndex];
            particle.lifetime = ps.lifetime[particleIndex];
            particle.rotation = ps.rotation[particleIndex];
            particle.axisOfRotation = ps.usesAxisOfRotation ? ps.axisOfRotation[particleIndex] : Vector3f::UNIT_Z;
            
            CalculateInheritedProperties(roState, inheritValues, subEmitterProperties, particle, state.system, t);
        }
        if(!state.recordSubEmits)
            RParticleSystem::Emit(*subEmitterData.emitter, SubEmitterEmitCommand(emissionState, initialPosition, initialVelocity, inheritValues, type, subEmitterIndex, amountOfParticlesToEmit, numContinuous, t, dt), kParticleSystemEMStaging);
        else if(!state.subEmitterCommandBuffer.IsFull())
            state.subEmitterCommandBuffer.AddCommand(emissionState, initialPosition, initialVelocity, inheritValues, type, subEmitterIndex, amountOfParticlesToEmit, numContinuous, t, dt);
    }
}

bool GetTransformationMatrix(Matrix4x4f& output, const bool isSystemInWorld, const bool isCurveInWorld, const Matrix4x4f& localToWorld)
{
    if(isCurveInWorld != isSystemInWorld)
    {
        if(isSystemInWorld)
            output = localToWorld;
        else
//            Matrix4x4f::Invert_General3D(localToWorld, output);
            output = localToWorld.getInversed();
        return true;
    }
    else
    {
//        output = Matrix4x4f::identity;
        output.setIdentity();
        return false;
    }
}

bool GetTransformationMatrices(Matrix4x4f& output, Matrix4x4f& outputInverse, const bool isSystemInWorld, const bool isCurveInWorld, const Matrix4x4f& localToWorld)
{
    if(isCurveInWorld != isSystemInWorld)
    {
        if(isSystemInWorld)
        {
            output = localToWorld;
//            Matrix4x4f::Invert_General3D(localToWorld, outputInverse);
            outputInverse = localToWorld.getInversed();
        }
        else
        {
//            Matrix4x4f::Invert_General3D(localToWorld, output);
            output = localToWorld.getInversed();
            outputInverse = localToWorld;
        }
        return true;
    }
    else
    {
//        output = Matrix4x4f::identity;
//        outputInverse = Matrix4x4f::identity;
        output.setIdentity();
        outputInverse.setIdentity();
        return false;
    }
}

NS_RRP_END