Cocoa Design Patterns
Learning OpenGL ES for iOS
Presentations
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  • Cocoa Design Patterns
    Cocoa Design Patterns
    by Erik M. Buck, Donald A. Yacktman
  • Learning OpenGL ES for iOS: A Hands-on Guide to Modern 3D Graphics Programming
    Learning OpenGL ES for iOS: A Hands-on Guide to Modern 3D Graphics Programming
    by Erik M. Buck

Errata > Incorrect diagram in Figure 4.5 (Not a Surface Normal)

The middle diagram in Figure 4.5 shows a Surface Normal, Light Direction and a Plane, but that is not a Surface Normal, because it is not perpendicular to the plane.
November 8, 2012 | Unregistered CommenterChad
Thank you for the feedback.

There is some imprecision in the way the center part of Figure 4.5 is drawn. It is certainly meant to depict a surface normal vector. The "plane" portions of all three parts of Figure 4.5 were originally drawn as triangles and then turned "edge on." It's possible the surface normal vector is correct as-is because we can't see the third vertex defining the triangle that defines the plane. I agree that a close inspection of the figure makes the surface normal vector seem not quite right.

Have you seen something else that I'm not noticing, or was that it?
November 9, 2012 | Registered CommenterErik Buck
I think that's mostly it. I was just expecting the Surface Normal to be at a true 90 degree angle with the Plane.

Thanks for responding. I'm loving the book!
November 9, 2012 | Unregistered CommenterChad