OpenGL 4 Shading Language Cookbook - Third Edition

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There are two important points to keep in mind about this technique. First, the objects will only reflect the environment map. They will not reflect the image of any other objects within the scene. In order to do so, we would need to generate an environment map from the point of view of each object by rendering the scene six times with the view point located at the center of the object and the view direction in each of the six coordinate directions. Then, we could use the appropriate environment map for the appropriate object's reflections. Of course, if any of the objects were to move relative to one another, we'd need to regenerate the environment maps. All of this effort may be prohibitive in an interactive application. ...