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

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.

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

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

#include "Game_local.h"

static const char* smokeParticle_SnapshotName = "_SmokeParticle_Snapshot_";

/*
================
idSmokeParticles::idSmokeParticles
================
*/
idSmokeParticles::idSmokeParticles()
{
	initialized = false;
	memset( &renderEntity, 0, sizeof( renderEntity ) );
	renderEntityHandle = -1;
	memset( smokes, 0, sizeof( smokes ) );
	freeSmokes = NULL;
	numActiveSmokes = 0;
	currentParticleTime = -1;
}

/*
================
idSmokeParticles::Init
================
*/
void idSmokeParticles::Init()
{
	if( initialized )
	{
		Shutdown();
	}
	
	// set up the free list
	for( int i = 0; i < MAX_SMOKE_PARTICLES - 1; i++ )
	{
		smokes[i].next = &smokes[i + 1];
	}
	smokes[MAX_SMOKE_PARTICLES - 1].next = NULL;
	freeSmokes = &smokes[0];
	numActiveSmokes = 0;
	
	activeStages.Clear();
	
	memset( &renderEntity, 0, sizeof( renderEntity ) );
	
	renderEntity.bounds.Clear();
	renderEntity.axis = mat3_identity;
	renderEntity.shaderParms[ SHADERPARM_RED ]		= 1;
	renderEntity.shaderParms[ SHADERPARM_GREEN ]	= 1;
	renderEntity.shaderParms[ SHADERPARM_BLUE ]		= 1;
	renderEntity.shaderParms[3] = 1;
	
	renderEntity.hModel = renderModelManager->AllocModel();
	renderEntity.hModel->InitEmpty( smokeParticle_SnapshotName );
	
	// we certainly don't want particle shadows
	renderEntity.noShadow = 1;
	
	// huge bounds, so it will be present in every world area
	renderEntity.bounds.AddPoint( idVec3( -100000, -100000, -100000 ) );
	renderEntity.bounds.AddPoint( idVec3( 100000,  100000,  100000 ) );
	
	renderEntity.callback = idSmokeParticles::ModelCallback;
	// add to renderer list
	renderEntityHandle = gameRenderWorld->AddEntityDef( &renderEntity );
	
	currentParticleTime = -1;
	
	initialized = true;
}

/*
================
idSmokeParticles::Shutdown
================
*/
void idSmokeParticles::Shutdown()
{
	// make sure the render entity is freed before the model is freed
	if( renderEntityHandle != -1 )
	{
		gameRenderWorld->FreeEntityDef( renderEntityHandle );
		renderEntityHandle = -1;
	}
	if( renderEntity.hModel != NULL )
	{
		renderModelManager->FreeModel( renderEntity.hModel );
		renderEntity.hModel = NULL;
	}
	initialized = false;
}

/*
================
idSmokeParticles::FreeSmokes
================
*/
void idSmokeParticles::FreeSmokes()
{
	for( int activeStageNum = 0; activeStageNum < activeStages.Num(); activeStageNum++ )
	{
		singleSmoke_t* smoke, *next, *last;
		
		activeSmokeStage_t* active = &activeStages[activeStageNum];
		const idParticleStage* stage = active->stage;
		
		for( last = NULL, smoke = active->smokes; smoke; smoke = next )
		{
			next = smoke->next;
			
			float frac;
			
			if( smoke->timeGroup )
			{
				frac = ( float )( gameLocal.fast.time - smoke->privateStartTime ) / ( stage->particleLife * 1000 );
			}
			else
			{
				frac = ( float )( gameLocal.slow.time - smoke->privateStartTime ) / ( stage->particleLife * 1000 );
			}
			if( frac >= 1.0f )
			{
				// remove the particle from the stage list
				if( last != NULL )
				{
					last->next = smoke->next;
				}
				else
				{
					active->smokes = smoke->next;
				}
				// put the particle on the free list
				smoke->next = freeSmokes;
				freeSmokes = smoke;
				numActiveSmokes--;
				continue;
			}
			
			last = smoke;
		}
		
		if( !active->smokes )
		{
			// remove this from the activeStages list
			activeStages.RemoveIndex( activeStageNum );
			activeStageNum--;
		}
	}
}

/*
================
idSmokeParticles::EmitSmoke

Called by game code to drop another particle into the list
================
*/
bool idSmokeParticles::EmitSmoke( const idDeclParticle* smoke, const int systemStartTime, const float diversity, const idVec3& origin, const idMat3& axis, int timeGroup /*_D3XP*/ )
{
	bool	continues = false;
	SetTimeState ts( timeGroup );
	
	if( !smoke )
	{
		return false;
	}
	
	if( !gameLocal.isNewFrame )
	{
		return false;
	}
	
	// dedicated doesn't smoke. No UpdateRenderEntity, so they would not be freed
	if( gameLocal.GetLocalClientNum() < 0 )
	{
		return false;
	}
	
	assert( gameLocal.time == 0 || systemStartTime <= gameLocal.time );
	if( systemStartTime > gameLocal.time )
	{
		return false;
	}
	
	idRandom steppingRandom( 0xffff * diversity );
	
	// for each stage in the smoke that is still emitting particles, emit a new singleSmoke_t
	for( int stageNum = 0; stageNum < smoke->stages.Num(); stageNum++ )
	{
		const idParticleStage* stage = smoke->stages[stageNum];
		
		if( !stage->cycleMsec )
		{
			continue;
		}
		
		if( !stage->material )
		{
			continue;
		}
		
		if( stage->particleLife <= 0 )
		{
			continue;
		}
		
		// see how many particles we should emit this tic
		// FIXME: 			smoke.privateStartTime += stage->timeOffset;
		int		finalParticleTime = stage->cycleMsec * stage->spawnBunching;
		int		deltaMsec = gameLocal.time - systemStartTime;
		
		int		nowCount = 0, prevCount = 0;
		if( finalParticleTime == 0 )
		{
			// if spawnBunching is 0, they will all come out at once
			if( gameLocal.time == systemStartTime )
			{
				prevCount = -1;
				nowCount = stage->totalParticles - 1;
			}
			else
			{
				prevCount = stage->totalParticles;
			}
		}
		else
		{
			nowCount = floor( ( ( float )deltaMsec / finalParticleTime ) * stage->totalParticles );
			if( nowCount >= stage->totalParticles )
			{
				nowCount = stage->totalParticles - 1;
			}
			prevCount = floor( ( ( float )( deltaMsec - ( gameLocal.time - gameLocal.previousTime ) ) / finalParticleTime ) * stage->totalParticles );
			if( prevCount < -1 )
			{
				prevCount = -1;
			}
		}
		
		if( prevCount >= stage->totalParticles )
		{
			// no more particles from this stage
			continue;
		}
		
		if( nowCount < stage->totalParticles - 1 )
		{
			// the system will need to emit particles next frame as well
			continues = true;
		}
		
		// find an activeSmokeStage that matches this
		activeSmokeStage_t*	active = NULL;
		int i;
		for( i = 0 ; i < activeStages.Num() ; i++ )
		{
			active = &activeStages[i];
			if( active->stage == stage )
			{
				break;
			}
		}
		if( i == activeStages.Num() )
		{
			// add a new one
			activeSmokeStage_t	newActive;
			
			newActive.smokes = NULL;
			newActive.stage = stage;
			i = activeStages.Append( newActive );
			active = &activeStages[i];
		}
		
		// add all the required particles
		for( prevCount++ ; prevCount <= nowCount && active != NULL ; prevCount++ )
		{
			if( !freeSmokes )
			{
				gameLocal.Printf( "idSmokeParticles::EmitSmoke: no free smokes with %d active stages\n", activeStages.Num() );
				return true;
			}
			singleSmoke_t*	newSmoke = freeSmokes;
			freeSmokes = freeSmokes->next;
			numActiveSmokes++;
			
			newSmoke->timeGroup = timeGroup;
			newSmoke->index = prevCount;
			newSmoke->axis = axis;
			newSmoke->origin = origin;
			newSmoke->random = steppingRandom;
			newSmoke->privateStartTime = systemStartTime + prevCount * finalParticleTime / stage->totalParticles;
			newSmoke->next = active->smokes;
			active->smokes = newSmoke;
			
			steppingRandom.RandomInt();	// advance the random
		}
	}
	
	return continues;
}

/*
================
idSmokeParticles::UpdateRenderEntity
================
*/
bool idSmokeParticles::UpdateRenderEntity( renderEntity_s* renderEntity, const renderView_t* renderView )
{

	// this may be triggered by a model trace or other non-view related source,
	// to which we should look like an empty model
	if( !renderView )
	{
		// FIXME: re-use model surfaces
		renderEntity->hModel->InitEmpty( smokeParticle_SnapshotName );
		return false;
	}
	
	// don't regenerate it if it is current
	if( renderView->time[renderEntity->timeGroup] == currentParticleTime && !renderView->forceUpdate )
	{
		return false;
	}
	
	// FIXME: re-use model surfaces
	renderEntity->hModel->InitEmpty( smokeParticle_SnapshotName );
	
	currentParticleTime = renderView->time[renderEntity->timeGroup];
	
	particleGen_t g;
	
	g.renderEnt = renderEntity;
	g.renderView = renderView;
	
	for( int activeStageNum = 0; activeStageNum < activeStages.Num(); activeStageNum++ )
	{
		singleSmoke_t* smoke, *next, *last;
		
		activeSmokeStage_t* active = &activeStages[activeStageNum];
		const idParticleStage* stage = active->stage;
		
		if( !stage->material )
		{
			continue;
		}
		
		// allocate a srfTriangles that can hold all the particles
		int count = 0;
		for( smoke = active->smokes; smoke; smoke = smoke->next )
		{
			count++;
		}
		int	quads = count * stage->NumQuadsPerParticle();
		srfTriangles_t* tri = renderEntity->hModel->AllocSurfaceTriangles( quads * 4, quads * 6 );
		tri->numIndexes = quads * 6;
		tri->numVerts = quads * 4;
		
		// just always draw the particles
		tri->bounds[0][0] =
			tri->bounds[0][1] =
				tri->bounds[0][2] = -99999;
		tri->bounds[1][0] =
			tri->bounds[1][1] =
				tri->bounds[1][2] = 99999;
				
		tri->numVerts = 0;
		for( last = NULL, smoke = active->smokes; smoke; smoke = next )
		{
			next = smoke->next;
			
			if( smoke->timeGroup )
			{
				g.frac = ( float )( gameLocal.fast.time - smoke->privateStartTime ) / ( stage->particleLife * 1000 );
			}
			else
			{
				g.frac = ( float )( gameLocal.time - smoke->privateStartTime ) / ( stage->particleLife * 1000 );
			}
			if( g.frac >= 1.0f )
			{
				// remove the particle from the stage list
				if( last != NULL )
				{
					last->next = smoke->next;
				}
				else
				{
					active->smokes = smoke->next;
				}
				// put the particle on the free list
				smoke->next = freeSmokes;
				freeSmokes = smoke;
				numActiveSmokes--;
				continue;
			}
			
			g.index = smoke->index;
			g.random = smoke->random;
			
			g.origin = smoke->origin;
			g.axis = smoke->axis;
			
			g.originalRandom = g.random;
			g.age = g.frac * stage->particleLife;
			
			tri->numVerts += stage->CreateParticle( &g, tri->verts + tri->numVerts );
			
			last = smoke;
		}
		if( tri->numVerts > quads * 4 )
		{
			gameLocal.Error( "idSmokeParticles::UpdateRenderEntity: miscounted verts" );
		}
		
		if( tri->numVerts == 0 )
		{
		
			// they were all removed
			renderEntity->hModel->FreeSurfaceTriangles( tri );
			
			if( !active->smokes )
			{
				// remove this from the activeStages list
				activeStages.RemoveIndex( activeStageNum );
				activeStageNum--;
			}
		}
		else
		{
			// build the index list
			int	indexes = 0;
			for( int i = 0 ; i < tri->numVerts ; i += 4 )
			{
				tri->indexes[indexes + 0] = i;
				tri->indexes[indexes + 1] = i + 2;
				tri->indexes[indexes + 2] = i + 3;
				tri->indexes[indexes + 3] = i;
				tri->indexes[indexes + 4] = i + 3;
				tri->indexes[indexes + 5] = i + 1;
				indexes += 6;
			}
			tri->numIndexes = indexes;
			
			modelSurface_t	surf;
			surf.geometry = tri;
			surf.shader = stage->material;
			surf.id = 0;
			
			renderEntity->hModel->AddSurface( surf );
		}
	}
	return true;
}

/*
================
idSmokeParticles::ModelCallback
================
*/
bool idSmokeParticles::ModelCallback( renderEntity_s* renderEntity, const renderView_t* renderView )
{
	// update the particles
	if( gameLocal.smokeParticles )
	{
		return gameLocal.smokeParticles->UpdateRenderEntity( renderEntity, renderView );
	}
	
	return true;
}