anchor.diff:  const String vNormal = "vNormal";
   const String vVertexPosition = "vVertexPosition";
   const String vCenter = "vCenter";
  +const String vDepth = "vDepth";
  +
   const String vPositionFromLight = "vPositionFromLight";
   
   // ===========================================================
  
positive.code: const String uLightTypes = "uLightTypes";
  
  final Map<String, ShaderVarDesc> _VarsDb = {
    eArray: new ShaderVarDesc("index", ""),
    eArrayType: new ShaderVarDesc("int", ""),
  
    //
    cBlend: new ShaderVarDesc("", ""),
  
negative.code: 
    bool IsScalarTypeFloat() {
      switch (type) {
        case VarTypeFloat:
        case VarTypeVec2:
        case VarTypeVec3:
        case VarTypeVec4:
          return true;
        default:
          return false;
  