ref: gl: add PARM_TEX_FILTERING handler

ref/gl/gl_context.c

@@ -167,6 +167,25 @@ qboolean Mod_ProcessRenderData( model_t *mod, qboolean create, const byte *buf )
 	return loaded;
 }
 
+static qboolean R_TextureFilteringEnabled( int arg )
+{
+	gl_texture_t *glt;
+
+	if( arg < 0 )
+		return gl_texture_nearest.value == 0.0f;
+
+	glt = R_GetTexture( arg );
+
+	if( FBitSet( glt->flags, TF_NEAREST ))
+		return false;
+
+	// lightmaps have special cvar
+	if( FBitSet( glt->flags, TF_ATLAS_PAGE ))
+		return gl_lightmap_nearest.value == 0.0f;
+
+	return gl_texture_nearest.value == 0.0f;
+}
+
 static int GL_RefGetParm( int parm, int arg )
 {
 	gl_texture_t *glt;
@@ -237,6 +256,8 @@ static int GL_RefGetParm( int parm, int arg )
 		return glState.stencilEnabled;
 	case PARM_SKY_SPHERE:
 		return FBitSet( tr.world->flags, FWORLD_SKYSPHERE ) && !FBitSet( tr.world->flags, FWORLD_CUSTOM_SKYBOX );
+	case PARM_TEX_FILTERING:
+		return R_TextureFilteringEnabled( arg );
 	default:
 		return ENGINE_GET_PARM_( parm, arg );
 	}