OpenGL2: Fix holodeck doors being black and not fading out

On Windows the opaque textures on the holodeck doors model were drawn
solid black and did not fade out.

Set up ref entity lightDir and modelLightDir as unit vectors. I am
guessing the vector lengths are being used as a divisor in a GLSL shader
or something.

Also clear directedLight so the same fields are set for RF_FULLBRIGHT as
all other ref entities.

code/renderergl1/tr_light.c

@@ -309,7 +309,10 @@ void R_SetupEntityLighting( const trRefdef_t *refdef, trRefEntity_t *ent ) {
 		((byte *)&ent->ambientLightInt)[2] = 0x7F;
 		((byte *)&ent->ambientLightInt)[3] = 0xFF;
 
-		ent->lightDir[0] = ent->lightDir[1] = ent->lightDir[2] = 0;
+		ent->directedLight[0] = ent->directedLight[1] = ent->directedLight[2] = 0;
+
+		ent->lightDir[0] = ent->lightDir[1] = 0;
+		ent->lightDir[2] = 1;
 		return;
 	}
 #endif

code/renderergl2/tr_light.c

@@ -340,7 +340,14 @@ void R_SetupEntityLighting( const trRefdef_t *refdef, trRefEntity_t *ent ) {
 		((byte *)&ent->ambientLightInt)[2] = 0x7F;
 		((byte *)&ent->ambientLightInt)[3] = 0xFF;
 
-		ent->lightDir[0] = ent->lightDir[1] = ent->lightDir[2] = 0;
+		ent->directedLight[0] = ent->directedLight[1] = ent->directedLight[2] = 0;
+
+		ent->lightDir[0] = ent->lightDir[1] = 0;
+		ent->lightDir[2] = 1;
+
+		ent->modelLightDir[0] = DotProduct( ent->lightDir, ent->e.axis[0] );
+		ent->modelLightDir[1] = DotProduct( ent->lightDir, ent->e.axis[1] );
+		ent->modelLightDir[2] = DotProduct( ent->lightDir, ent->e.axis[2] );
 		return;
 	}
 #endif