/*==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/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/

#include "hsTypes.h"
#include "hsMemory.h"
#include "hsSfxDistFade.h"
#include "hsStream.h"
#include "../plPipeline/plPipeline.h"
#include "../plGeometry/hsTriangle3.h"
#include "../plDrawable/plDrawable.h"

#include "../plIntersect/hsBounds.h"


static hsScalar globalScale = 1.f;

hsSfxDistFade::hsSfxDistFade()
: fMinDist(0), fMaxDist(0)
{
}

hsSfxDistFade::~hsSfxDistFade()
{
}

hsScalar hsSfxDistFade::IOpacFromDist(hsScalar dist)
{
    if( dist <= fTable[0].fDistDel )
        return fTable[0].fOpacity;

    int i;
    for( i = 0; (i < fTable.GetCount()) && (dist >= fTable[i].fDistDel); i++ )
        dist -= fTable[i].fDistDel;

    if( i >= fTable.GetCount() )
        return fTable[fTable.GetCount()-1].fOpacity;

    dist *= fTable[i-1].fDistNorm;
    hsScalar opac0 = fTable[i-1].fOpacity;
    hsScalar opac1 = fTable[i].fOpacity;

    return opac0 + dist * (opac1 - opac0);
}

hsBool32 hsSfxDistFade::BeginObject(plPipeline* pipe, plDrawable* obj)
{
    hsGRenderProcs::BeginObject(pipe, obj);

    fFlags &= ~(kCulled | kNOP);

    hsPoint3 vPos;
    if( GetObjectRef(1) )
    {
        hsPoint3 wPos;
        GetObjectRef(1)->GetLocalToWorld().GetTranslate(&wPos);
        hsMatrix44 w2l = fPipeline->GetWorldToLocal();
        vPos = w2l * wPos;
    }
    else
    {
        vPos = fPipeline->GetViewPositionLocal();
    }

    hsScalar scale = 1.f / fPipeline->GetLocalScale();
    scale *= globalScale;

    const hsBounds3Ext& bnd = obj->GetLocalBounds();

    hsPoint3 inner, outer;
    bnd.ClosestPoint(vPos, inner, outer);

    hsScalar minDist, maxDist;

    minDist = hsVector3(&vPos, &inner).Magnitude();
    maxDist = hsVector3(&vPos, &outer).Magnitude();

    minDist *= scale;
    maxDist *= scale;

    if( (fFlags & kCullsBefore)
        &&(maxDist <= fMinDist) )
    {
        fFlags |= kCulled;
        return false;
    }

    if( (fFlags & kCullsBeyond)
        &&(minDist > fMaxDist) )
    {
        fFlags |= kCulled;
        return false;
    }

    if( (fFlags & kIdleBefore)
        &&(maxDist < fMinIdle) )
        fFlags |= kNOP;

    if( (fFlags & kIdleBeyond)
        &&(minDist > fMaxIdle) )
        fFlags |= kNOP;

    return true;
}

void hsSfxDistFade::ProcessPreInterpShadeVerts(hsExpander<hsGShadeVertex*>& vList)
{
    if( fFlags & (kPostInterp | kNOP) )
        return;

    hsPoint3 vPos;
    if( GetObjectRef(1) )
    {
        hsPoint3 wPos;
        GetObjectRef(1)->GetLocalToWorld().GetTranslate(&wPos);
        hsMatrix44 w2l = fPipeline->GetWorldToLocal();
        vPos = w2l * wPos;
    }
    else
    {
        vPos = fPipeline->GetViewPositionLocal();
    }
    hsScalar scale = 1.f / fPipeline->GetLocalScale();

    scale *= globalScale;
    
    for( vList.First(); vList.More(); vList.Plus() )
    {
        hsGShadeVertex* shade = vList.Current();

        hsScalar dist = hsVector3(&shade->fLocalPos, &vPos).Magnitude();
        dist *= scale;

        hsScalar opac = IOpacFromDist(dist);

        if( opac > 0 )
            shade->fShade.a *= opac;
        else
        {
            shade->fShade.a = 0;
            shade->fBaseVertex->fFlags |= hsGVertex3::kCulled;
        }
    }
}

void hsSfxDistFade::ProcessPostInterpShadeVerts(hsExpander<hsGShadeVertex*>& vList)
{
    if( !(fFlags & kPostInterp) )
        return;

    if( fFlags & kNOP )
        return;

    hsPoint3 vPos;
    if( GetObjectRef(1) )
    {
        hsPoint3 wPos;
        GetObjectRef(1)->GetLocalToWorld().GetTranslate(&wPos);
        hsMatrix44 w2l = fPipeline->GetWorldToLocal();
        vPos = w2l * wPos;
    }
    else
    {
        vPos = fPipeline->GetViewPositionLocal();
    }
    hsScalar scale = 1.f / fPipeline->GetLocalScale();
    
    for( vList.First(); vList.More(); vList.Plus() )
    {
        hsGShadeVertex* shade = vList.Current();

        hsScalar dist = hsVector3(&shade->fLocalPos, &vPos).Magnitude();
        dist *= scale;

        hsScalar opac = IOpacFromDist(dist);

        if( opac > 0 )
            shade->fColor.a *= opac;
        else
        {
            shade->fColor.a = 0;
            shade->fBaseVertex->fFlags |= hsGVertex3::kCulled;
        }
    }
}

void hsSfxDistFade::MakeTable(float* distList, float* opacList, int num)
{
    fTable.Reset();
    if( !num )
        return;

    int i;
    for( i = 0; i < num; i++ )
    {
        hsSfxDfTableEntry* t = fTable.Append();
        t->fDistDel = distList[i];
        t->fOpacity = opacList[i];
    }
    for( i = num-1; i > 0; i-- )
        fTable[i].fDistDel -= fTable[i-1].fDistDel;
    for( i = 0; i < num-1; i++ )
        fTable[i].fDistNorm = hsScalarInvert(fTable[i+1].fDistDel);
    fTable[num-1].fDistNorm = 0;
    hsAssert(fTable.GetCount() == num, "Mismatch making table");

    if( fTable[0].fOpacity <= 0 )
        fFlags |= kCullsBefore;
    if( fTable[num-1].fOpacity <= 0 )
        fFlags |= kCullsBeyond;
    if( fTable[0].fOpacity >= 1.f )
        fFlags |= kIdleBefore;
    if( fTable[num-1].fOpacity >= 1.f )
        fFlags |= kIdleBeyond;

    int iMin;
    for( iMin = 0; (iMin < fTable.GetCount())&&(fTable[iMin].fOpacity <= 0); iMin++ );
    fMinDist = fTable[0].fDistDel;
    for( i = 1; i < iMin; i++ )
        fMinDist += fTable[i].fDistDel;

    for( iMin = 0; (iMin < fTable.GetCount())&&(fTable[iMin].fOpacity >= 1.f); iMin++ );
    fMinIdle = fTable[0].fDistDel;
    for( i = 1; i < iMin; i++ )
        fMinIdle += fTable[i].fDistDel;

    int iMax;
    for( iMax = fTable.GetCount()-1; (iMax >= 0)&&(fTable[iMax].fOpacity <= 0); iMax-- );
    if( ++iMax >= fTable.GetCount() )
        iMax = fTable.GetCount()-1;
    fMaxDist = fTable[0].fDistDel;
    for( i = 1; i <= iMax; i++ )
        fMaxDist += fTable[i].fDistDel;

    for( iMax = fTable.GetCount()-1; (iMax >= 0)&&(fTable[iMax].fOpacity >= 1.f); iMax-- );
    if( ++iMax >= fTable.GetCount() )
        iMax = fTable.GetCount()-1;
    fMaxIdle = fTable[0].fDistDel;
    for( i = 1; i <= iMax; i++ )
        fMaxIdle += fTable[i].fDistDel;
}

void hsSfxDistFade::Read(hsStream* s)
{
    fTable.Reset();

    fMinDist = s->ReadSwapScalar();
    fMaxDist = s->ReadSwapScalar();

    if( fFlags & (kIdleBefore | kIdleBeyond) )
    {
        fMinIdle = s->ReadSwapScalar();
        fMaxIdle = s->ReadSwapScalar();
    }

    Int32 cnt = s->ReadSwap32();

    if( cnt )
    {
        hsSfxDfTableEntry* arr = new hsSfxDfTableEntry[cnt];
        int i;
        for( i = 0; i < cnt; i++ )
        {
            arr[i].fDistDel = s->ReadSwapScalar();
            arr[i].fDistNorm = s->ReadSwapScalar();
            arr[i].fOpacity = s->ReadSwapScalar();
        }

        fTable.SetArray(arr, cnt);
    }
}

void hsSfxDistFade::Write(hsStream* s)
{
    s->WriteSwapScalar(fMinDist);
    s->WriteSwapScalar(fMaxDist);

    if( fFlags & (kIdleBefore | kIdleBeyond) )
    {
        s->WriteSwapScalar(fMinIdle);
        s->WriteSwapScalar(fMaxIdle);
    }

    s->WriteSwap32(fTable.GetCount());

    for( fTable.First(); fTable.More(); fTable.Plus() )
    {
        s->WriteSwapScalar(fTable.Current().fDistDel);
        s->WriteSwapScalar(fTable.Current().fDistNorm);
        s->WriteSwapScalar(fTable.Current().fOpacity);
    }
}