message: fix missing uniform in direct-volume shader
diff: @@ -74,6 +74,7 @@ uniform vec3 uFogColor;
  uniform float uAlpha;
  uniform float uPickingAlphaThreshold;
  uniform bool uTransparentBackground;
  +uniform float uXrayEdgeFalloff;
  uniform float uInteriorDarkening;
  uniform bool uInteriorColorFlag;
  