/* ------------------------------------------------------------------------- */
 // File       : LensFlare.cpp
 // Project    : Long Forgotten Earth
 // Author     : David de Lorenzo
 /* ------------------------------------------------------------------------- */
 
 #include "LensFlare.h"
 
 /* ------------------------------------------------------------------------- */
 /// Constructor
 /// @param LightPosition The 3D position of the Light, relative to the camera.
 /// @param camera        The camera on which the lensflare effect will appear.
 /// @param SceneMgr      Pointer on the SceneManager.
 /* ------------------------------------------------------------------------- */
 LensFlare::LensFlare(Vector3 LightPosition, Camera* camera, SceneManager* SceneMgr)
 {
 	mSceneMgr      = SceneMgr;
 	mCamera        = camera;
 	mHidden        = true;
 	this->createLensFlare();
 	this->setLightPosition(LightPosition);
 }
 
 /* ------------------------------------------------------------------------- */
 /// Destructor
 /* ------------------------------------------------------------------------- */
 LensFlare::~LensFlare()
 {
 	mNode->detachObject(mHaloSet);
 	mNode->detachObject(mBurstSet);
 	mSceneMgr->destroyBillboardSet(mHaloSet);
 	mSceneMgr->destroyBillboardSet(mBurstSet);
 	/// TODO destroy mNode
 } 
 
 
 /* ------------------------------------------------------------------------- */
 /// this function creates and shows all the LensFlare graphical elements.
 /* ------------------------------------------------------------------------- */
 void LensFlare::createLensFlare()
 {
 	Real LF_scale = 2000;
 
 	// -----------------------------------------------------
 	// We create 2 sets of billboards for the lensflare
 	// -----------------------------------------------------
 	mHaloSet = mSceneMgr->createBillboardSet("halo");
 	mHaloSet->setMaterialName("lensflare/halo");
 	mHaloSet->setCullIndividually(true);
 	mHaloSet->setQueryFlags(0);	// They should not be detected by rays.
 
 	mBurstSet= mSceneMgr->createBillboardSet("burst");
 	mBurstSet->setMaterialName("lensflare/burst");
 	mBurstSet->setCullIndividually(true);
 	mBurstSet->setQueryFlags(0);	
 
 	// The node is located at the light source.
 	mNode  = mSceneMgr->getRootSceneNode()->createChildSceneNode();
 
 	mNode->attachObject(mBurstSet);
 	mNode->attachObject(mHaloSet);
 
 	// -------------------------------
 	// Creation of the Halo billboards
 	// -------------------------------
 	Billboard* LF_Halo1 = mHaloSet->createBillboard(0,0,0);
 	LF_Halo1->setDimensions(LF_scale*0.5,LF_scale*0.5);
 	Billboard* LF_Halo2 = mHaloSet->createBillboard(0,0,0);
 	LF_Halo2->setDimensions(LF_scale,LF_scale);
 	Billboard* LF_Halo3 = mHaloSet->createBillboard(0,0,0);
 	LF_Halo3->setDimensions(LF_scale*0.25,LF_scale*0.25);
 
 
 	// -------------------------------
 	// Creation of the "Burst" billboards
 	// -------------------------------
 	Billboard* LF_Burst1 = mBurstSet->createBillboard(0,0,0);
 	LF_Burst1->setDimensions(LF_scale*0.25,LF_scale*0.25);
 	Billboard* LF_Burst2 = mBurstSet->createBillboard(0,0,0);
 	LF_Burst2->setDimensions(LF_scale*0.5,LF_scale*0.5);
 	Billboard* LF_Burst3 = mBurstSet->createBillboard(0,0,0);
 	LF_Burst3->setDimensions(LF_scale*0.25,LF_scale*0.25);
 
 } 
 
 
 /* -------------------------------------------------------------------------- */
 /// This function updates the lensflare effect. 
 /** This function should be called by your frameListener.
 */
 /* -------------------------------------------------------------------------- */
 void LensFlare::update()
{
   // If the Light is out of the Camera field Of View, the lensflare is hidden.
   if (!mCamera->isVisible(mLightPosition)) 
   {
      mHaloSet->setVisible(false);
      mBurstSet->setVisible(false);
      return;
   }
   else
   {
      mHaloSet->setVisible(true);
      mBurstSet->setVisible(true);
   }
 
   Real LightDistance  = mLightPosition.distance(mCamera->getPosition());
   Vector3 CameraVect  = mCamera->getDirection(); // normalized vector (length 1)
 
   CameraVect = mCamera->getPosition() + (LightDistance * CameraVect);
 
 
   // The LensFlare effect takes place along this vector.
   Vector3 LFvect = (CameraVect - mLightPosition);
   //LFvect += Vector3(-64,-64,0);  // sprite dimension (to be adjusted, but not necessary)
 
   // The different sprites are placed along this line.
   mHaloSet->getBillboard(0)->setPosition( LFvect*0.500);
   mHaloSet->getBillboard(1)->setPosition( LFvect*0.125);
   mHaloSet->getBillboard(2)->setPosition(-LFvect*0.250);
 
   mBurstSet->getBillboard(0)->setPosition( LFvect*0.333);
   mBurstSet->getBillboard(1)->setPosition(-LFvect*0.500);
   mBurstSet->getBillboard(2)->setPosition(-LFvect*0.180);
 
   // We redraw the lensflare (in case it was previouly out of the camera field, and hidden)
   this->setVisible(true);   
}
 
 
 /* ------------------------------------------------------------------------- */
 /// This function shows (or hide) the lensflare effect.
 /* ------------------------------------------------------------------------- */
 void LensFlare::setVisible(bool visible)
 {
 	mHaloSet->setVisible(visible);
 	mBurstSet->setVisible(visible);
 	mHidden = !visible;
 }
 
 
 /* ------------------------------------------------------------------------- */
 /// This function updates the light source position. 
 /** This function can be used if the light source is moving.*/
 /* ------------------------------------------------------------------------- */
 void LensFlare::setLightPosition(Vector3 pos)
 {
 	mLightPosition = pos;
 	mNode->setPosition(mLightPosition); 
 }
 
 
 /* ------------------------------------------------------------------------- */
 /// This function changes the colour of the burst. 
 /* ------------------------------------------------------------------------- */
 void LensFlare::setBurstColour(ColourValue color)
 {
 	mBurstSet->getBillboard(0)->setColour(color);
 	mBurstSet->getBillboard(1)->setColour(color*0.8);
 	mBurstSet->getBillboard(2)->setColour(color*0.6);
 } 
 
 /* ------------------------------------------------------------------------- */
 /// This function changes the colour of the halos. 
 /* ------------------------------------------------------------------------- */
 void LensFlare::setHaloColour(ColourValue color)
 { 
 	mHaloSet->getBillboard(0)->setColour(color*0.8);
 	mHaloSet->getBillboard(1)->setColour(color*0.6);
 	mHaloSet->getBillboard(2)->setColour(color);
 }