Errata.GraphicsGemsIV

Errata to _Graphics Gems IV_, first edition, edited by Paul Heckbert,
Academic Press 1994.  Code available online at http://www.graphicsgems.org

compiled by Eric Haines (erich@acm.org) from author and reader contributions

version 1.5
date:  9/10/2008

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Errors in the text:

p. xvi, near the bottom of the page: change
    "in directory pub/GraphicsGems/GemsIV"
    to
    "in directory pub/Graphics/GraphicsGems/GemsIV".


p. 129, lines 4,7,10:  changes:
        "if (x < 0)" to "if (x >= 0)",
        "if (y < 0)" to "if (y >= 0)",
        "if (z < 0)" to "if (z >= 0)".

p. 138, first equation: change "(-ax,ay)" to "(-ay,ax)" to match the text.

p. 349, for (Moore 1992):  change "Rice University, Houston, TX" to "Cornell
    University, Ithaca, NY".

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The following are errors in the book's code listings (corrected in the online
code at http://www.graphicsgems.org/). This list is not complete, as changes
from 2013 on are tracked on Github; see the online code for the most current
and correct version.


Serious errors (ones your compiler cannot or may not catch):

p. 273, 11 lines from the bottom:
        B[0], umid, u1, depthb,
    to:
        B[1], umid, u1, depthb,
    (thanks to Frank Rosfelder)

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Syntax errors (ones that are not usually harmful, or are easily caught):

[none so far]

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The following are errors in the comments:

p. 136, line 10: change
    "The N data points have indices which range from 0 to N-1."
    to "The data points have indices which range from 0 to N."
    (thanks to Michael Ford, 9/10/2008)

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A new point in polygon test has been added to ptpoly_haines/ptinpoly.c, a
variation on the Crossings test which is about 15% faster for triangles.
This CrossingsMultiply test avoids using division.

A potential divide by zero error has been removed from
ptpoly_haines/ptinpoly.c; line 1286 had "inv_y = tmax / ydiff;", which is
now deleted.

END