anchor.diff:    position_attrib_index: integer;
   
     vertex_data: packed array[1..8] of GLdouble;
  +const
  +  index_data: packed array[1..4] of GLUint = (0,sizeof(GLdouble),sizeof(GLdouble)*2,sizeof(GLdouble)*3);
   begin
     ShaderContext.SetFragmentColor(RECT_COLOR);
     glLineWidth(1);
  
positive.code:     DefaultProjMatrixUniform: GLuint;
      DefaultCoordsAttrib: GLuint;
  
      CoordsBuffer: GLuint;
    public
      destructor Destroy; override;
      procedure Init;
  
negative.code:   DefaultProjMatrixUniform := glGetUniformLocation(DefaultProgram, PChar('projMatrix'));
    DefaultCoordsAttrib := glGetAttribLocation(DefaultProgram, PChar('coords'));
  
    CheckGLErrors('compiling default vertex shader1');
  
    glGenVertexArrays(1,@CoordsArray);
    glGenBuffers(1,@CoordsBuffer);
    //glBindBuffer(GL_ARRAY_BUFFER,CoordsBuffer);
    glBindVertexArray(ShaderContext.CoordsArray);
  
    CheckGLErrors('VBO');
  end;
  
  procedure TShaderContext.SetFlagColor(FlagColor: TRBGAColor);
  