half lambert lighting by jal (option: -lightanglehl)

tools/quake3/q3map2/game_darkplaces.h

@@ -58,6 +58,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	0.3f,				/* lightgrid scale */
 	0.6f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
 	qtrue,				/* keep light entities on bsp */
 	4,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_dq.h

@@ -58,6 +58,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	0.3f,				/* lightgrid scale */
 	0.6f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
 	qtrue,				/* keep light entities on bsp */
 	4,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_ef.h

@@ -117,6 +117,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_etut.h

@@ -152,6 +152,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_ja.h

@@ -71,6 +71,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_jk2.h

@@ -68,6 +68,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_nexuiz.h

@@ -67,6 +67,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
 	qtrue,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_prophecy.h

@@ -58,6 +58,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	0.4f,				/* lightgrid scale */
 	0.6f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
 	qtrue,				/* keep light entities on bsp */
 	4,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_qfusion.h

@@ -119,10 +119,11 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qtrue,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
-	qfalse,				/* keep light entities on bsp */
+	qtrue,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */
-	qfalse,				/* patch casting enabled */
+	qtrue,				/* patch casting enabled */
 	qtrue,				/* compile deluxemaps */
 	0,					/* deluxemaps default mode */
 	256,                /* minimap size */

tools/quake3/q3map2/game_quake3.h

@@ -116,6 +116,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_quakelive.h

@@ -68,6 +68,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_sof2.h

@@ -143,6 +143,7 @@ game_t struct
 	1.0f,					/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_tenebrae.h

@@ -116,6 +116,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qtrue,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_tremulous.h

@@ -74,6 +74,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_wolf.h

@@ -133,6 +133,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/game_wolfet.h

@@ -70,6 +70,7 @@ game_t struct
 	1.0f,				/* lightmap compensate */
 	1.0f,				/* lightgrid scale */
 	1.0f,				/* lightgrid ambient scale */
+	qfalse,				/* light angle attenuation uses half-lambert curve */
 	qfalse,				/* disable shader lightstyles hack */
 	qfalse,				/* keep light entities on bsp */
 	8,					/* default patchMeta subdivisions tolerance */

tools/quake3/q3map2/light.c

@@ -865,7 +865,33 @@ int LightContributionToSample( trace_t *trace )
 			dist = 16.0f;
 		
 		/* angle attenuation */
-		angle = (light->flags & LIGHT_ATTEN_ANGLE) ? DotProduct( trace->normal, trace->direction ) : 1.0f;
+		if( light->flags & LIGHT_ATTEN_ANGLE )
+		{
+			/* standard Lambert attenuation */
+			float dot = DotProduct( trace->normal, trace->direction ); 
+
+			/* twosided lighting */
+			if( trace->twoSided )
+				dot = fabs( dot );
+
+			/* jal: optional half Lambert attenuation (http://developer.valvesoftware.com/wiki/Half_Lambert) */
+			if( lightAngleHL )
+			{
+				if( dot > 0.001f ) // skip coplanar
+				{
+					if( dot > 1.0f ) dot = 1.0f;
+					dot = ( dot * 0.5f ) + 0.5f;
+					dot *= dot;
+				}
+				else
+					dot = 0;
+			}
+
+			angle = dot;
+		}
+		else
+			angle = 1.0f;
+
 		if( light->angleScale != 0.0f )
 		{
 			angle /= light->angleScale;
@@ -873,10 +899,6 @@ int LightContributionToSample( trace_t *trace )
 				angle = 1.0f;
 		}
 		
-		/* twosided lighting */
-		if( trace->twoSided )
-			angle = fabs( angle );
-		
 		/* attenuate */
 		if( light->flags & LIGHT_ATTEN_LINEAR )
 		{
@@ -918,15 +940,34 @@ int LightContributionToSample( trace_t *trace )
 		/* get origin and direction */
 		VectorAdd( trace->origin, light->origin, trace->end );
 		dist = SetupTrace( trace );
-		
+
 		/* angle attenuation */
-		angle = (light->flags & LIGHT_ATTEN_ANGLE)
-			? DotProduct( trace->normal, trace->direction )
-			: 1.0f;
-		
-		/* twosided lighting */
-		if( trace->twoSided )
-			angle = fabs( angle );
+		if( light->flags & LIGHT_ATTEN_ANGLE )
+		{
+			/* standard Lambert attenuation */
+			float dot = DotProduct( trace->normal, trace->direction ); 
+
+			/* twosided lighting */
+			if( trace->twoSided )
+				dot = fabs( dot );
+
+			/* jal: optional half Lambert attenuation (http://developer.valvesoftware.com/wiki/Half_Lambert) */
+			if( lightAngleHL )
+			{
+				if( dot > 0.001f ) // skip coplanar
+				{
+					if( dot > 1.0f ) dot = 1.0f;
+					dot = ( dot * 0.5f ) + 0.5f;
+					dot *= dot;
+				}
+				else
+					dot = 0;
+			}
+			
+			angle = dot;
+		}
+		else
+			angle = 1.0f;
 		
 		/* attenuate */
 		add = light->photons * angle;
@@ -1880,6 +1921,10 @@ int LightMain( int argc, char **argv )
 	gridAmbientScale = game->gridAmbientScale;
 	Sys_Printf( " lightgrid ambient scale: %f\n", gridAmbientScale );
 
+	lightAngleHL = game->lightAngleHL;
+	if( lightAngleHL )
+		Sys_Printf( " half lambert light angle attenuation enabled \n" );
+
 	noStyles = game->noStyles;
 	if (noStyles == qtrue)
 		Sys_Printf( " shader lightstyles hack: disabled\n" );
@@ -2416,6 +2461,17 @@ int LightMain( int argc, char **argv )
 			loMem = qtrue;
 			Sys_Printf( "Enabling low-memory (potentially slower) lighting mode\n" );
 		}
+		else if( !strcmp( argv[ i ], "-lightanglehl" ) )
+		{
+			if( ( atoi( argv[ i + 1 ] ) != 0 ) != lightAngleHL )
+			{
+				lightAngleHL = ( atoi( argv[ i + 1 ] ) != 0 );
+				if( lightAngleHL )
+					Sys_Printf( "Enabling half lambert light angle attenuation\n" );
+				else
+					Sys_Printf( "Disabling half lambert light angle attenuation\n" );
+			}
+		}
 		else if( !strcmp( argv[ i ], "-nostyle" ) || !strcmp( argv[ i ], "-nostyles" ) )
 		{
 			noStyles = qtrue;

tools/quake3/q3map2/q3map2.h

@@ -562,6 +562,7 @@ typedef struct game_s
 	float				lightmapCompensate;				/* default lightmap compensate value */
 	float				gridScale;						/* vortex: default lightgrid scale (affects both directional and ambient spectres) */
 	float				gridAmbientScale;				/* vortex: default lightgrid ambient spectre scale */
+	qboolean			lightAngleHL;					/* jal: use half-lambert curve for light angle attenuation */
 	qboolean			noStyles;						/* use lightstyles hack or not */
 	qboolean			keepLights;						/* keep light entities on bsp */
 	int					patchSubdivisions;				/* default patch subdivisions tolerance */
@@ -2217,6 +2218,9 @@ Q_EXTERN float				pointScale Q_ASSIGN( 7500.0f );
 Q_EXTERN float				areaScale Q_ASSIGN( 0.25f );
 Q_EXTERN float				skyScale Q_ASSIGN( 1.0f );
 Q_EXTERN float				bounceScale Q_ASSIGN( 0.25f );
+
+/* jal: alternative angle attenuation curve */
+Q_EXTERN qboolean			lightAngleHL Q_ASSIGN( qfalse );
  
 /* vortex: gridscale and gridambientscale */
 Q_EXTERN float				gridScale Q_ASSIGN( 1.0f );