CWE-ou-minkata/Sources/Plasma/PubUtilLib/plPipeline/plFogEnvironment.cpp

/*==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/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
NVIDIA PhysX SDK, Microsoft DirectX SDK, OpenSSL library, Independent
JPEG Group JPEG library, Microsoft Windows Media SDK, or Apple QuickTime SDK
(or a modified version of those libraries),
containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
PhysX SDK EULA, DirectX SDK EULA, OpenSSL and SSLeay licenses, IJG
JPEG Library README, Windows Media SDK EULA, or QuickTime SDK EULA, the
licensors of this Program grant you additional
permission to convey the resulting work. Corresponding Source for a
non-source form of such a combination shall include the source code for
the parts of OpenSSL and IJG JPEG Library used as well as that of the covered
work.

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==*/
//////////////////////////////////////////////////////////////////////////////
//																			//
//	plFogEnvironment.cpp - Functions for the fog volume class				//
//																			//
//////////////////////////////////////////////////////////////////////////////

#include "plFogEnvironment.h"

#include "plTweak.h"

//// Constructors & Destructor ///////////////////////////////////////////////

plFogEnvironment::plFogEnvironment()
{
	fType = kNoFog;
}

plFogEnvironment::plFogEnvironment( hsScalar start, hsScalar end, hsScalar density, hsColorRGBA &color )
{
	Set( start, end, density, &color );
}

plFogEnvironment::plFogEnvironment( FogType type, hsScalar end, hsScalar density, hsColorRGBA &color )
{
	SetExp( type, end, density, &color );
}

plFogEnvironment::~plFogEnvironment()
{
}

//// Set /////////////////////////////////////////////////////////////////////

void	plFogEnvironment::Set( hsScalar start, hsScalar end, hsScalar density, const hsColorRGBA *color )
{
	if( density <= 0.f )
	{
		fType = kNoFog;
		fStart = 0.f;
		fEnd = 0.f;
		fDensity = 0.f;
	}
	else
	{
		fType = kLinearFog;
		fStart = start;
		fEnd = end;
		fDensity = density;
	}
	if( color != nil )
		fColor = *color;
}

void	plFogEnvironment::SetExp( FogType type, hsScalar end, hsScalar density, const hsColorRGBA *color )
{
	hsAssert( type == kExpFog || type == kExp2Fog, "Invalid fog type passed to plFogEnvironment" );
	if( density <= 0.f )
	{
		fType = kNoFog;
		fStart = 0.f;
		fEnd = 0.f;
		fDensity = 0.f;
	}
	else
	{
		fType = type;
		fStart = 0.0f;
		fEnd = end;
		fDensity = density;
	}
	if( color != nil )
		fColor = *color;
}

//// GetParameters ///////////////////////////////////////////////////////////
//	Gets the parameters. Sets start to 0 if the type is not linear (can be
//	nil).

void	plFogEnvironment::GetParameters( hsScalar *start, hsScalar *end, hsScalar *density, hsColorRGBA *color )
{
	hsAssert( fType != kLinearFog || start != nil, "Trying to get non-linear paramters on linear fog!" );
	hsAssert( end != nil && density != nil && color != nil, "Bad pointer to plFogEnvironment::GetParameters()" );

	if( fType == kLinearFog )
		*start = fStart;
	else if( start != nil )
		*start = 0.0f;

	*end = fEnd;
	*density = fDensity;
	*color = fColor;
}

//// GetPipelineParams ///////////////////////////////////////////////////////
//	Gets linear pipeline (DX8) specific parameters. Basically massages our
//	interface values into values that DX8 can use. In this case, we simply
//	scale our end value out by the density. The whole formula is:
//		pipelineEnd = ( end - start ) / density + start

void	plFogEnvironment::GetPipelineParams( hsScalar *start, hsScalar *end, hsColorRGBA *color )
{
//	hsAssert( fType == kLinearFog, "Getting linear pipeline params on non-linear fog!" );

	*color = fColor;
	switch(fType)
	{
	case kLinearFog:
		*start = fStart;
		*end = (fEnd - fStart) / fDensity + fStart;
		break;
	case kExpFog:
		{
			plConst(float) kKnee(0.0f);
			*start = fEnd * kKnee;
			*end = (fEnd - *start) / fDensity + *start;
		}
		break;
	default:
	case kExp2Fog:
		{
			plConst(float) kKnee(0.3f);
			*start = fEnd * kKnee;
			*end = (fEnd - *start) / fDensity + *start;
		}
		break;
	}
}

//// GetPipelineParams ///////////////////////////////////////////////////////
//	Gets exp/exp^2 pipeline (DX8) specific parameters. Basically massages our
//	interface values into values that DX8 can use. In this case, we're going
//	to modulate the density by the end value so that it actually ends at the
//	right spot. 

void	plFogEnvironment::GetPipelineParams( hsScalar *density, hsColorRGBA *color )
{
	const float ln256		= logf( 256.f );
	const float sqrtLn256	= sqrtf( ln256 );

	
	hsAssert( fType == kExpFog || fType == kExp2Fog, "Getting non-linear pipeline params on linear fog!" );

	*density = ( ( fType == kExpFog ) ? ln256: sqrtLn256 ) * fDensity / fEnd;
	*color = fColor;
}

//// Read ////////////////////////////////////////////////////////////////////

void	plFogEnvironment::Read( hsStream *s, hsResMgr *mgr )
{
	hsKeyedObject::Read( s, mgr );

	fType = s->ReadByte();
	fStart = s->ReadSwapFloat();
	fEnd = s->ReadSwapFloat();
	fDensity = s->ReadSwapFloat();
	fColor.Read( s );
}

//// Write ///////////////////////////////////////////////////////////////////

void	plFogEnvironment::Write( hsStream *s, hsResMgr *mgr )
{
	hsKeyedObject::Write( s, mgr );

	s->WriteByte( fType );
	s->WriteSwapFloat( fStart );
	s->WriteSwapFloat( fEnd );
	s->WriteSwapFloat( fDensity );
	fColor.Write( s );
}