anchor.diff:    double angle1 = radians(rot_y);
     worldMatrix.rotateY(angle1);
     
  -  cameraMatrix = makeViewMatrix(new Vector3(0.0, 0.0, 8.0), new Vector3.zero(), new Vector3(0.0, 1.0, 0.0));
  +  cameraMatrix = makeViewMatrix(new Vector3(0.0, 5.0, 8.0), new Vector3.zero(), new Vector3(0.0, 1.0, 0.0));
     
     // set matrix uniforms.
     Float32List mat = new Float32List(16);
     
  +  // pass matrices to shader variable
     worldMatrix.copyIntoArray(mat);
     _gl.uniformMatrix4fv(worldMatrixLoc, false, mat);
     
  
positive.code:   _gl.useProgram(shaderProgram);
    
    
    // logs of compiled status
    if (!_gl.getShaderParameter(vertexShader, wgl.RenderingContext.COMPILE_STATUS)) { 
      print(_gl.getShaderInfoLog(vertexShader));
    }
  
negative.code:   vpWidth = glCanvas.width;
    vpHeight = glCanvas.height;
    
    _gl = glCanvas.getContext("webgl");
    _gl.enable(wgl.RenderingContext.DEPTH_TEST);
    
    _initVertexBuffer();
  