void GLMesh::fillPickBuffers()
{
    int tris = (int)(mesh.faces.size() - mesh.boundaries.size());
    
    // add faces
    int i = 0;
    pickVertices.resize(3*tris);
    for (FaceCIter f = mesh.faces.begin(); f != mesh.faces.end(); f++) {
        if (!f->isBoundary()) {
            int j = 0;
            Eigen::Vector3f color = elementColor(f->index);
            
            HalfEdgeCIter h = f->he;
            do {
                // set vertex
                pickVertices[3*i+j].position = h->vertex->position.cast<float>();
                pickVertices[3*i+j].color = color;
                j++;
                
                h = h->next;
            } while (h != f->he);
            i++;
        }
    }
    
    // add vertex faces
    int verts = 0;
    for (VertexCIter v = mesh.vertices.begin(); v != mesh.vertices.end(); v++) {
        verts += v->degree();
        if (v->isBoundary()) verts -= 1;
    }
    
    pickVertices.resize(3*(tris + verts));
    for (VertexCIter v = mesh.vertices.begin(); v != mesh.vertices.end(); v++) {
        Eigen::Vector3d n = 0.0015*v->normal();
        Eigen::Vector3f p1 = (v->position + n).cast<float>();
        Eigen::Vector3f color = elementColor(tris + v->index);
        
        HalfEdgeCIter h = v->he;
        do {
            if (!h->onBoundary) {
                Eigen::Vector3f p2 = (h->next->vertex->position + n).cast<float>();
                Eigen::Vector3f p3 = (h->next->next->vertex->position + n).cast<float>();
                
                pickVertices[3*i+0].position = p1;
                pickVertices[3*i+1].position = p1 + 0.125*(p2 - p1);
                pickVertices[3*i+2].position = p1 + 0.125*(p3 - p1);
                pickVertices[3*i+0].color = pickVertices[3*i+1].color = pickVertices[3*i+2].color = color;
                i++;
            }
            h = h->flip->next;
        } while (h != v->he);
    }
}
void LightFlareData::prepRender( SceneState *state, LightFlareState *flareState )
{    
   PROFILE_SCOPE( LightFlareData_prepRender );

   // No elements then nothing to render.
   if ( mElementCount == 0 )
      return;

   // We need these all over the place later.
   const Point3F &camPos = state->getCameraPosition();
   const RectI &viewport = GFX->getViewport();
   const Point3F &lightPos = flareState->lightMat.getPosition();
   LightInfo *lightInfo = flareState->lightInfo;

   bool isVectorLight = lightInfo->getType() == LightInfo::Vector;

   // Perform visibility testing on the light...
   // Project the light position from world to screen space, we need this
   // position later, and it tells us if it is actually onscreen.   
   
   Point3F lightPosSS;
   bool onscreen = MathUtils::mProjectWorldToScreen( lightPos, &lightPosSS, viewport, GFX->getWorldMatrix(), gClientSceneGraph->getNonClipProjection() );  

   U32 visDelta = U32_MAX;
   U32 fadeOutTime = 20;
   U32 fadeInTime = 125;    

   // Fade factor based on amount of occlusion.
   F32 occlusionFade = 1.0f;

   bool lightVisible = true;
   
   if ( !state->isReflectPass() )
   {
      // It is onscreen, so raycast as a simple occlusion test.

      U32 losMask =	STATIC_COLLISION_MASK |
                     ShapeBaseObjectType |
                     StaticTSObjectType |
                     ItemObjectType |
                     PlayerObjectType;

      GameConnection *conn = GameConnection::getConnectionToServer();
      if ( !conn )
         return;

      bool needsRaycast = true;

      // NOTE: if hardware does not support HOQ it will return NULL
      // and we will retry every time but there is not currently a good place
      // for one-shot initialization of LightFlareState
      if ( flareState->occlusionQuery == NULL )
         flareState->occlusionQuery = GFX->createOcclusionQuery();
      if ( flareState->fullPixelQuery == NULL )
         flareState->fullPixelQuery = GFX->createOcclusionQuery();

      if ( flareState->occlusionQuery && 
           ( ( isVectorLight && flareState->worldRadius > 0.0f ) || 
             ( !isVectorLight && mOcclusionRadius > 0.0f ) ) )
      {
         // Always treat light as onscreen if using HOQ
         // it will be faded out if offscreen anyway.
         onscreen = true;

         U32 pixels = -1;
         GFXOcclusionQuery::OcclusionQueryStatus status = flareState->occlusionQuery->getStatus( true, &pixels );

         String str = flareState->occlusionQuery->statusToString( status );
         Con::setVariable( "$Flare::OcclusionStatus", str.c_str() );
         Con::setIntVariable( "$Flare::OcclusionVal", pixels );
         
         if ( status == GFXOcclusionQuery::Occluded )
            occlusionFade = 0.0f;

         if ( status != GFXOcclusionQuery::Unset )         
            needsRaycast = false;

         RenderPassManager *pass = state->getRenderPass();

         OccluderRenderInst *ri = pass->allocInst<OccluderRenderInst>();   

         Point3F scale( Point3F::One );

         if ( isVectorLight && flareState->worldRadius > 0.0f )         
            scale *= flareState->worldRadius;
         else
            scale *= mOcclusionRadius;
         
         ri->type = RenderPassManager::RIT_Occluder;
         ri->query = flareState->occlusionQuery;   
         ri->query2 = flareState->fullPixelQuery;
         ri->position = lightPos;
         ri->scale = scale;
         ri->orientation = pass->allocUniqueXform( lightInfo->getTransform() );         
         ri->isSphere = true;
         state->getRenderPass()->addInst( ri );

         if ( status == GFXOcclusionQuery::NotOccluded )
         {
            U32 fullPixels;
            flareState->fullPixelQuery->getStatus( true, &fullPixels );

            occlusionFade = (F32)pixels / (F32)fullPixels;

            // Approximation of the full pixel count rather than doing
            // two queries, but it is not very accurate.
            /*
            F32 dist = ( camPos - lightPos ).len();
            F32 radius = scale.x;
            radius = ( radius / dist ) * state->getWorldToScreenScale().y;

            occlusionFade = (F32)pixels / (4.0f * radius * radius);
            occlusionFade = mClampF( occlusionFade, 0.0f, 1.0f );            
            */
         }
      }

      Con::setFloatVariable( "$Flare::OcclusionFade", occlusionFade );

      if ( needsRaycast )
      {
         // Use a raycast to determine occlusion.

         bool fps = conn->isFirstPerson();

         GameBase *control = conn->getControlObject();
         if ( control && fps )
            control->disableCollision();

         RayInfo rayInfo;

         if ( gClientContainer.castRayRendered( camPos, lightPos, losMask, &rayInfo ) )
            occlusionFade = 0.0f;

         if ( control && fps )
            control->enableCollision();
      }

      lightVisible = onscreen && occlusionFade > 0.0f;

      // To perform a fade in/out when we gain or lose visibility
      // we must update/store the visibility state and time.

      U32 currentTime = Sim::getCurrentTime();

      if ( lightVisible != flareState->visible )
      {
         flareState->visible = lightVisible;
         flareState->visChangedTime = currentTime;
      }      

      // Save this in the state so that we have it during the reflect pass.
      flareState->occlusion = occlusionFade;

      visDelta = currentTime - flareState->visChangedTime;      
   }
   else // state->isReflectPass()
   {
      occlusionFade = flareState->occlusion;
      lightVisible = flareState->visible;
      visDelta = Sim::getCurrentTime() - flareState->visChangedTime;
   }

   // We can only skip rendering if the light is not visible, and it
   // has elapsed the fadeOutTime.
   if ( !lightVisible && visDelta > fadeOutTime )
      return;

   // In a reflection we only render the elements with zero distance.   
   U32 elementCount = mElementCount;
   if ( state->isReflectPass()  )
   {
      elementCount = 0;
      for ( ; elementCount < mElementCount; elementCount++ )
      {
         if ( mElementDist[elementCount] > 0.0f )
            break;
      }
   }

   if ( elementCount == 0 )
      return;

   // A bunch of preparatory math before generating verts...

   const Point2I &vpExtent = viewport.extent;
   Point3F viewportExtent( vpExtent.x, vpExtent.y, 1.0f );
   Point2I halfViewportExtentI( viewport.extent / 2 );
   Point3F halfViewportExtentF( (F32)halfViewportExtentI.x * 0.5f, (F32)halfViewportExtentI.y, 0.0f );
   Point3F screenCenter( 0,0,0 );
   Point3F oneOverViewportExtent( 1.0f / viewportExtent.x, 1.0f / viewportExtent.y, 1.0f );

   lightPosSS.y -= viewport.point.y;
   lightPosSS *= oneOverViewportExtent;
   lightPosSS = ( lightPosSS * 2.0f ) - Point3F::One;
   lightPosSS.y = -lightPosSS.y;
   lightPosSS.z = 0.0f;

   Point3F flareVec( screenCenter - lightPosSS );
   F32 flareLength = flareVec.len();   
   flareVec.normalizeSafe();

   Point3F basePoints[4];
   basePoints[0] = Point3F( -0.5, 0.5, 0.0 );  
   basePoints[1] = Point3F( -0.5, -0.5, 0.0 );   
   basePoints[2] = Point3F( 0.5, -0.5, 0.0 );   
   basePoints[3] = Point3F( 0.5, 0.5, 0.0 );

   Point3F rotatedBasePoints[4];
   rotatedBasePoints[0] = basePoints[0];
   rotatedBasePoints[1] = basePoints[1];
   rotatedBasePoints[2] = basePoints[2];
   rotatedBasePoints[3] = basePoints[3];

   Point3F fvec( -1, 0, 0 );   
   F32 rot = mAcos( mDot( fvec, flareVec ) );
   Point3F rvec( 0, -1, 0 );
   rot *= mDot( rvec, flareVec ) > 0.0f ? 1.0f : -1.0f;

   vectorRotateZAxis( rotatedBasePoints[0], rot );
   vectorRotateZAxis( rotatedBasePoints[1], rot );
   vectorRotateZAxis( rotatedBasePoints[2], rot );
   vectorRotateZAxis( rotatedBasePoints[3], rot );

   // Here we calculate a the light source's influence on the effect's size
   // and brightness...

   // Scale based on the current light brightness compared to its normal output.
   F32 lightSourceBrightnessScale = lightInfo->getBrightness() / flareState->fullBrightness;
   // Scale based on world space distance from camera to light source.
   F32 lightSourceWSDistanceScale = ( isVectorLight ) ? 1.0f : getMin( 10.0f / ( lightPos - camPos ).len(), 1.5f );   
   // Scale based on screen space distance from screen position of light source to the screen center.
   F32 lightSourceSSDistanceScale = ( 1.5f - ( lightPosSS - screenCenter ).len() ) / 1.5f;

   // Scale based on recent visibility changes, fading in or out.
   F32 fadeInOutScale = 1.0f;
   if ( lightVisible && visDelta < fadeInTime && flareState->occlusion )
      fadeInOutScale = (F32)visDelta / (F32)fadeInTime;
   else if ( !lightVisible && visDelta < fadeOutTime )
      fadeInOutScale = 1.0f - (F32)visDelta / (F32)fadeOutTime;

   // This combined scale influences the size of all elements this effect renders.
   // Note we also add in a scale that is user specified in the Light.
   F32 lightSourceIntensityScale = lightSourceBrightnessScale * 
                                   lightSourceWSDistanceScale * 
                                   lightSourceSSDistanceScale * 
                                   fadeInOutScale * 
                                   flareState->scale *
                                   occlusionFade;

   // The baseColor which modulates the color of all elements.
   ColorF baseColor;
   if ( flareState->fullBrightness == 0.0f )
      baseColor = ColorF::BLACK;
   else
      // These are the factors which affect the "alpha" of the flare effect.
      // Modulate more in as appropriate.
      baseColor = ColorF::WHITE * lightSourceBrightnessScale * occlusionFade;

   // Fill in the vertex buffer...
   const U32 vertCount = 4 * elementCount;
   if (  flareState->vertBuffer.isNull() || 
         flareState->vertBuffer->mNumVerts != vertCount )
         flareState->vertBuffer.set( GFX, vertCount, GFXBufferTypeDynamic );

   GFXVertexPCT *pVert = flareState->vertBuffer.lock();

   const Point2I &widthHeightI = mFlareTexture.getWidthHeight();
   Point2F oneOverTexSize( 1.0f / (F32)widthHeightI.x, 1.0f / (F32)widthHeightI.y );

   for ( U32 i = 0; i < elementCount; i++ )
   {      
      Point3F *basePos = mElementRotate[i] ? rotatedBasePoints : basePoints;

      ColorF elementColor( baseColor * mElementTint[i] );
      if ( mElementUseLightColor[i] )
         elementColor *= lightInfo->getColor();

      Point3F elementPos;
      elementPos = lightPosSS + flareVec * mElementDist[i] * flareLength;      
      elementPos.z = 0.0f;

      F32 maxDist = 1.5f;
      F32 elementDist = mSqrt( ( elementPos.x * elementPos.x ) + ( elementPos.y * elementPos.y ) );
      F32 distanceScale = ( maxDist - elementDist ) / maxDist;
      distanceScale = 1.0f;

      const RectF &elementRect = mElementRect[i];
      Point3F elementSize( elementRect.extent.x, elementRect.extent.y, 1.0f );
      elementSize *= mElementScale[i] * distanceScale * mScale * lightSourceIntensityScale;

      if ( elementSize.x < 100.0f )
      {
         F32 alphaScale = mPow( elementSize.x / 100.0f, 2 );
         elementColor *= alphaScale;
      }

      elementColor.clamp();

      Point2F texCoordMin, texCoordMax;
      texCoordMin = elementRect.point * oneOverTexSize;
      texCoordMax = ( elementRect.point + elementRect.extent ) * oneOverTexSize;          

      pVert->color = elementColor;
      pVert->point = ( basePos[0] * elementSize * oneOverViewportExtent ) + elementPos;      
      pVert->texCoord.set( texCoordMin.x, texCoordMax.y );
      pVert++;

      pVert->color = elementColor;
      pVert->point = ( basePos[1] * elementSize * oneOverViewportExtent ) + elementPos;
      pVert->texCoord.set( texCoordMax.x, texCoordMax.y );
      pVert++;

      pVert->color = elementColor;
      pVert->point = ( basePos[2] * elementSize * oneOverViewportExtent ) + elementPos;
      pVert->texCoord.set( texCoordMax.x, texCoordMin.y );
      pVert++;

      pVert->color = elementColor;
      pVert->point = ( basePos[3] * elementSize * oneOverViewportExtent ) + elementPos;
      pVert->texCoord.set( texCoordMin.x, texCoordMin.y );
      pVert++;
   }   

   flareState->vertBuffer.unlock();   

   // Create and submit the render instance...
   
   RenderPassManager *renderManager = state->getRenderPass();
   ParticleRenderInst *ri = renderManager->allocInst<ParticleRenderInst>();

   ri->vertBuff = &flareState->vertBuffer;
   ri->primBuff = &mFlarePrimBuffer;
   ri->translucentSort = true;
   ri->type = RenderPassManager::RIT_Particle;
   ri->sortDistSq = ( lightPos - camPos ).lenSquared();

   ri->modelViewProj = &MatrixF::Identity;
   ri->bbModelViewProj = ri->modelViewProj;

   ri->count = elementCount;

   // Only draw the light flare in high-res mode, never off-screen mode
   ri->systemState = ParticleRenderInst::AwaitingHighResDraw;

   ri->blendStyle = ParticleRenderInst::BlendGreyscale;

   ri->diffuseTex = &*(mFlareTexture);

   ri->softnessDistance = 1.0f; 

   // Sort by texture too.
   ri->defaultKey = ri->diffuseTex ? (U32)ri->diffuseTex : (U32)ri->vertBuff;

   renderManager->addInst( ri );
}