/*
===========================================================================

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  

Doom 3 BFG Edition Source Code 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.

Doom 3 BFG Edition Source Code 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 Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

#pragma hdrstop
#include "../idlib/precompiled.h"

#include "tr_local.h"
#include "Model_local.h"

static const char *parametricParticle_SnapshotName = "_ParametricParticle_Snapshot_";

/*
====================
idRenderModelPrt::idRenderModelPrt
====================
*/
idRenderModelPrt::idRenderModelPrt() {
	particleSystem = NULL;
}

/*
====================
idRenderModelPrt::InitFromFile
====================
*/
void idRenderModelPrt::InitFromFile( const char *fileName ) {
	name = fileName;
	particleSystem = static_cast<const idDeclParticle *>( declManager->FindType( DECL_PARTICLE, fileName ) );
}

/*
=================
idRenderModelPrt::TouchData
=================
*/
void idRenderModelPrt::TouchData() {
	// Ensure our particle system is added to the list of referenced decls
	particleSystem = static_cast<const idDeclParticle *>( declManager->FindType( DECL_PARTICLE, name ) );
}

/*
====================
idRenderModelPrt::InstantiateDynamicModel
====================
*/
idRenderModel *idRenderModelPrt::InstantiateDynamicModel( const struct renderEntity_s *renderEntity, const viewDef_t *viewDef, idRenderModel *cachedModel ) {
	idRenderModelStatic	*staticModel;

	if ( cachedModel && !r_useCachedDynamicModels.GetBool() ) {
		delete cachedModel;
		cachedModel = NULL;
	}

	// this may be triggered by a model trace or other non-view related source, to which we should look like an empty model
	if ( renderEntity == NULL || viewDef == NULL ) {
		delete cachedModel;
		return NULL;
	}

	if ( r_skipParticles.GetBool() ) {
		delete cachedModel;
		return NULL;
	}

	/*
	// if the entire system has faded out
	if ( renderEntity->shaderParms[SHADERPARM_PARTICLE_STOPTIME] && viewDef->renderView.time * 0.001f >= renderEntity->shaderParms[SHADERPARM_PARTICLE_STOPTIME] ) {
		delete cachedModel;
		return NULL;
	}
	*/

	if ( cachedModel != NULL ) {

		assert( dynamic_cast<idRenderModelStatic *>(cachedModel) != NULL );
		assert( idStr::Icmp( cachedModel->Name(), parametricParticle_SnapshotName ) == 0 );

		staticModel = static_cast<idRenderModelStatic *>(cachedModel);

	} else {

		staticModel = new (TAG_MODEL) idRenderModelStatic;
		staticModel->InitEmpty( parametricParticle_SnapshotName );
	}

	particleGen_t g;

	g.renderEnt = renderEntity;
	g.renderView = &viewDef->renderView;
	g.origin.Zero();
	g.axis.Identity();

	for ( int stageNum = 0; stageNum < particleSystem->stages.Num(); stageNum++ ) {
		idParticleStage *stage = particleSystem->stages[stageNum];

		if ( !stage->material ) {
			continue;
		}
		if ( !stage->cycleMsec ) {
			continue;
		}
		if ( stage->hidden ) {		// just for gui particle editor use
			staticModel->DeleteSurfaceWithId( stageNum );
			continue;
		}

		idRandom steppingRandom, steppingRandom2;

		int stageAge = g.renderView->time[renderEntity->timeGroup] + renderEntity->shaderParms[SHADERPARM_TIMEOFFSET] * 1000 - stage->timeOffset * 1000;
		int	stageCycle = stageAge / stage->cycleMsec;

		// some particles will be in this cycle, some will be in the previous cycle
		steppingRandom.SetSeed( (( stageCycle << 10 ) & idRandom::MAX_RAND) ^ (int)( renderEntity->shaderParms[SHADERPARM_DIVERSITY] * idRandom::MAX_RAND )  );
		steppingRandom2.SetSeed( (( (stageCycle-1) << 10 ) & idRandom::MAX_RAND) ^ (int)( renderEntity->shaderParms[SHADERPARM_DIVERSITY] * idRandom::MAX_RAND )  );

		int	count = stage->totalParticles * stage->NumQuadsPerParticle();

		int surfaceNum;
		modelSurface_t *surf;

		if ( staticModel->FindSurfaceWithId( stageNum, surfaceNum ) ) {
			surf = &staticModel->surfaces[surfaceNum];
			R_FreeStaticTriSurfVertexCaches( surf->geometry );
		} else {
			surf = &staticModel->surfaces.Alloc();
			surf->id = stageNum;
			surf->shader = stage->material;
			surf->geometry = R_AllocStaticTriSurf();
			R_AllocStaticTriSurfVerts( surf->geometry, 4 * count );
			R_AllocStaticTriSurfIndexes( surf->geometry, 6 * count );
		}

		int numVerts = 0;
		idDrawVert *verts = surf->geometry->verts;

		for ( int index = 0; index < stage->totalParticles; index++ ) {
			g.index = index;

			// bump the random
			steppingRandom.RandomInt();
			steppingRandom2.RandomInt();

			// calculate local age for this index 
			int	bunchOffset = stage->particleLife * 1000 * stage->spawnBunching * index / stage->totalParticles;

			int particleAge = stageAge - bunchOffset;
			int	particleCycle = particleAge / stage->cycleMsec;
			if ( particleCycle < 0 ) {
				// before the particleSystem spawned
				continue;
			}
			if ( stage->cycles && particleCycle >= stage->cycles ) {
				// cycled systems will only run cycle times
				continue;
			}

			if ( particleCycle == stageCycle ) {
				g.random = steppingRandom;
			} else {
				g.random = steppingRandom2;
			}

			int	inCycleTime = particleAge - particleCycle * stage->cycleMsec;

			if ( renderEntity->shaderParms[SHADERPARM_PARTICLE_STOPTIME] && 
				g.renderView->time[renderEntity->timeGroup] - inCycleTime >= renderEntity->shaderParms[SHADERPARM_PARTICLE_STOPTIME]*1000 ) {
				// don't fire any more particles
				continue;
			}

			// supress particles before or after the age clamp
			g.frac = (float)inCycleTime / ( stage->particleLife * 1000 );
			if ( g.frac < 0.0f ) {
				// yet to be spawned
				continue;
			}
			if ( g.frac > 1.0f ) {
				// this particle is in the deadTime band
				continue;
			}

			// this is needed so aimed particles can calculate origins at different times
			g.originalRandom = g.random;

			g.age = g.frac * stage->particleLife;

			// if the particle doesn't get drawn because it is faded out or beyond a kill region, don't increment the verts
			numVerts += stage->CreateParticle( &g, verts + numVerts );
		}

		// numVerts must be a multiple of 4
		assert( ( numVerts & 3 ) == 0 && numVerts <= 4 * count );

		// build the indexes
		int	numIndexes = 0;
		triIndex_t *indexes = surf->geometry->indexes;
		for ( int i = 0; i < numVerts; i += 4 ) {
			indexes[numIndexes+0] = i+0;
			indexes[numIndexes+1] = i+2;
			indexes[numIndexes+2] = i+3;
			indexes[numIndexes+3] = i+0;
			indexes[numIndexes+4] = i+3;
			indexes[numIndexes+5] = i+1;
			numIndexes += 6;
		}

		surf->geometry->tangentsCalculated = false;
		surf->geometry->numVerts = numVerts;
		surf->geometry->numIndexes = numIndexes;
		surf->geometry->bounds = stage->bounds;		// just always draw the particles
	}

	return staticModel;
}

/*
====================
idRenderModelPrt::IsDynamicModel
====================
*/
dynamicModel_t idRenderModelPrt::IsDynamicModel() const {
	return DM_CONTINUOUS;
}

/*
====================
idRenderModelPrt::Bounds
====================
*/
idBounds idRenderModelPrt::Bounds( const struct renderEntity_s *ent ) const {
	return particleSystem->bounds;
}

/*
====================
idRenderModelPrt::DepthHack
====================
*/
float idRenderModelPrt::DepthHack() const {
	return particleSystem->depthHack;
}

/*
====================
idRenderModelPrt::Memory
====================
*/
int idRenderModelPrt::Memory() const {
	int total = 0;

	total += idRenderModelStatic::Memory();

	if ( particleSystem ) {
		total += sizeof( *particleSystem );

		for ( int i = 0; i < particleSystem->stages.Num(); i++ ) {
			total += sizeof( particleSystem->stages[i] );
		}
	}

	return total;
}