diff --git a/code/renderer/tr_light.cpp b/code/renderer/tr_light.cpp
index 6a29f9e..0337056 100644
--- a/code/renderer/tr_light.cpp
+++ b/code/renderer/tr_light.cpp
@@ -112,10 +112,8 @@ static void R_SetupEntityLightingGrid( trRefEntity_t *ent ) {
 		float	factor;
 		byte	*data;
 		vec3_t	normal;
-		#if idppc
-		float d0, d1, d2, d3, d4, d5;
-		#endif
-		factor = 1.0;
+
+		factor = 1.0f;
 		data = gridData;
 		for ( j = 0 ; j < 3 ; j++ ) {
 			if ( i & (1<<j) ) {
@@ -130,18 +128,7 @@ static void R_SetupEntityLightingGrid( trRefEntity_t *ent ) {
 			continue;	// ignore samples in walls
 		}
 		totalFactor += factor;
-		#if idppc
-		d0 = data[0]; d1 = data[1]; d2 = data[2];
-		d3 = data[3]; d4 = data[4]; d5 = data[5];
 
-		ent->ambientLight[0] += factor * d0;
-		ent->ambientLight[1] += factor * d1;
-		ent->ambientLight[2] += factor * d2;
-
-		ent->directedLight[0] += factor * d3;
-		ent->directedLight[1] += factor * d4;
-		ent->directedLight[2] += factor * d5;
-		#else
 		ent->ambientLight[0] += factor * data[0];
 		ent->ambientLight[1] += factor * data[1];
 		ent->ambientLight[2] += factor * data[2];
@@ -149,7 +136,6 @@ static void R_SetupEntityLightingGrid( trRefEntity_t *ent ) {
 		ent->directedLight[0] += factor * data[3];
 		ent->directedLight[1] += factor * data[4];
 		ent->directedLight[2] += factor * data[5];
-		#endif
 
 		const float lat = (float)data[7] * (2.0f * M_PI / 256.0f);
 		const float lon = (float)data[6] * (2.0f * M_PI / 256.0f);
@@ -164,7 +150,7 @@ static void R_SetupEntityLightingGrid( trRefEntity_t *ent ) {
 		VectorMA( direction, factor, normal, direction );
 	}
 
-	if ( totalFactor > 0 && totalFactor < 0.99 ) {
+	if ( totalFactor > 0.0f && totalFactor < 0.99f ) {
 		totalFactor = 1.0f / totalFactor;
 		VectorScale( ent->ambientLight, totalFactor, ent->ambientLight );
 		VectorScale( ent->directedLight, totalFactor, ent->directedLight );
diff --git a/code/renderer/tr_local.h b/code/renderer/tr_local.h
index 51d7e1a..5e7d0cf 100644
--- a/code/renderer/tr_local.h
+++ b/code/renderer/tr_local.h
@@ -776,11 +776,12 @@ typedef struct {
 	int			numfogs;
 	fog_t		*fogs;
 
-	vec3_t		lightGridOrigin;
-	vec3_t		lightGridSize;
-	vec3_t		lightGridInverseSize;
-	int			lightGridBounds[3];
-	byte		*lightGridData;
+	vec3_t		lightGridOrigin;		// center of the voxel at (0, 0, 0)
+	vec3_t		lightGridSize;			// world units per voxel
+	vec3_t		lightGridInverseSize;	// reciprocal world units per voxel
+	int			lightGridBounds[3];		// voxel counts
+	byte		*lightGridData;			// 8 bytes per voxel: ambient RGB, light RGB + longitude + latitude
+										// indexing: x + y*w + z*w*h
 
 	int			numClusters;
 	int			clusterBytes;