OpenGL Preview

Here is an example of an OpenGL preview. The black and white image is the preview generated by OpenGL. The small image in the corner is the raytraced scene. As you can see, the OpenGL preview has the same shape as the actual image. The preview is really just intended to give a rough approximation of what the actual scene will look like. The preview doesn't try to simulate the material properties or the shadows/reflections that may be present in the ray traced image.