tr_light.cpp

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
Copyright (C) 2006-2011 Robert Beckebans <trebor_7@users.sourceforge.net>

This file is part of Daemon source code.

Daemon 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 2 of the License,
or (at your option) any later version.

Daemon 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 Daemon source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// tr_light.c
#include "tr_local.h"

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

LIGHT SAMPLING

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

void R_InterpolateLightGrid( world_t *w, int from[3], int to[3], float *factors[3],
		vec3_t lightColor, vec3_t lightDir )
{
	float           totalFactor = 0.0f, factor;
	float           *xFactor, *yFactor, *zFactor;
	int             gridStep[ 3 ];
	int             x, y, z;
	bspGridPoint1_t *gp1;
	bspGridPoint2_t *gp2;

	VectorClear( lightColor );
	VectorClear( lightDir );

	gridStep[ 0 ] = 1;
	gridStep[ 1 ] = w->lightGridBounds[ 0 ];
	gridStep[ 2 ] = gridStep[ 1 ] * w->lightGridBounds[ 1 ];

	for( x = from[ 0 ], xFactor = factors[ 0 ]; x <= to[ 0 ];
	     x++, xFactor++ ) {
		if( x < 0 || x >= w->lightGridBounds[ 0 ] )
			continue;

		for( y = from[ 1 ], yFactor = factors[ 1 ]; y <= to[ 1 ];
		     y++, yFactor++ ) {
			if( y < 0 || y >= w->lightGridBounds[ 1 ] )
				continue;

			for( z = from[ 2 ], zFactor = factors[ 2 ]; z <= to[ 2 ];
			     z++, zFactor++ ) {
				if( z < 0 || z >= w->lightGridBounds[ 2 ] )
					continue;

				gp1 = w->lightGridData1 + x * gridStep[ 0 ] + y * gridStep[ 1 ] + z * gridStep[ 2 ];
				gp2 = w->lightGridData2 + x * gridStep[ 0 ] + y * gridStep[ 1 ] + z * gridStep[ 2 ];

				if ( !gp2->isSet )
				{
					continue; // ignore samples in walls
				}

				factor = *xFactor * *yFactor * *zFactor;

				totalFactor += factor;

				lightDir[ 0 ] += factor * snorm8ToFloat( gp2->direction[ 0 ] - 128 );
				lightDir[ 1 ] += factor * snorm8ToFloat( gp2->direction[ 1 ] - 128 );
				lightDir[ 2 ] += factor * snorm8ToFloat( gp2->direction[ 2 ] - 128 );

				lightColor[ 0 ] += factor * unorm8ToFloat( gp1->color[ 0 ] );
				lightColor[ 1 ] += factor * unorm8ToFloat( gp1->color[ 1 ] );
				lightColor[ 2 ] += factor * unorm8ToFloat( gp1->color[ 2 ] );
			}
		}
	}

	if ( totalFactor > 0.0f )
	{
		VectorScale( lightDir, 1.0f / totalFactor, lightDir );
		VectorScale( lightColor, 1.0f / totalFactor, lightColor );
	}
}