94 lines
4.6 KiB
Markdown
94 lines
4.6 KiB
Markdown
---
|
|
title: Michael Abrash's Graphics Programming Black Book, Special Edition
|
|
author: Michael Abrash
|
|
date: '1997-07-01'
|
|
identifier:
|
|
- scheme: ISBN
|
|
text: 1576101746
|
|
publisher: The Coriolis Group
|
|
category: 'Web and Software Development: Game Development,Web and Software Development:
|
|
Graphics and Multimedia Development'
|
|
---
|
|
|
|
# Afterword
|
|
|
|
If you've followed me this far, you might agree that we've come through
|
|
some rough country. Still, I'm of the opinion that hard-won knowledge is
|
|
the best knowledge, not only because it sticks to you better, but also
|
|
because winning a hard race makes it easier to win the next one.
|
|
|
|
This is an unusual book in that sense: In addition to being a
|
|
compilation of much of what I know about fast computer graphics, it is a
|
|
journal recording some of the process by which I discovered and refined
|
|
that knowledge. I didn't just sit down one day to write this book—I
|
|
wrote it over a period of years and published its component parts in
|
|
many places. It is a journal of my successes and frustrations, with side
|
|
glances of my life as it happened along the way.
|
|
|
|
And there is yet another remarkable thing about this book: You, the
|
|
reader, helped me write it. Perhaps not you personally, but many people
|
|
who have read my articles and columns over the years sent me notes
|
|
asking me questions, suggesting improvements (occasionally by daring me
|
|
to beat them at the code performance game!) or sometimes just dumping
|
|
remarkable code into my lap. Where it seemed appropriate, I dropped in
|
|
the code and sometimes even the words of my correspondents, and the book
|
|
is much the richer for it.
|
|
|
|
Here and there, I learned things that had nothing at all to do with fast
|
|
graphics.
|
|
|
|
For example: I'm not a doomsayer who thinks American education lags
|
|
hopelessly behind the rest of the Western world, but now and then
|
|
something happens that makes me wonder. Some time back, I received a
|
|
letter from one Melvyn J. Lafitte requesting that I spend some time in
|
|
my columns describing fast 3-D animation techniques. Melvyn hoped that I
|
|
would be so kind as to discuss, among other things, hidden surface
|
|
removal and perspective projection, performed in real time, of course,
|
|
and preferably in Mode X. Sound familiar?
|
|
|
|
Melvyn shared with me a hidden surface approach that he had developed.
|
|
His technique involved defining polygon vertices in clockwise order, as
|
|
viewed from the visible side. Then, he explained, one can use the
|
|
cross-product equations found in any math book to determine which way
|
|
the perpendicular to the polygon is pointing. Better yet, he pointed
|
|
out, it's necessary to calculate only the Z component of the
|
|
perpendicular, and only the sign of the Z component need actually be
|
|
tested.
|
|
|
|
What Melvyn described is, of course, backface removal, a key
|
|
hidden-surface technique that I used heavily in X-Sharp. In general,
|
|
other hidden surface techniques must be used in conjunction with
|
|
backface removal, but backface removal is nonetheless important and
|
|
highly efficient. Simply put, Melvyn had devised for himself one of the
|
|
fundamental techniques of 3-D drawing.
|
|
|
|
Melvyn lives in Moens, France. At the time he wrote me, Melvyn was 17
|
|
years old. Try to imagine any American 17-year-old of your acquaintance
|
|
inventing backface removal. Try to imagine any teenager you know even
|
|
using the phrase "the cross-product equations found in any math book."
|
|
Not to mention that Melvyn was able to write a highly technical letter
|
|
in English; and if Melvyn's English was something less than flawless, it
|
|
was perfectly understandable, and, in my experience, vastly better than
|
|
an average, or even well-educated, American's French. Please understand,
|
|
I believe we Americans excel in a wide variety of ways, but I worry that
|
|
when it comes to math and foreign languages, we are becoming a nation of
|
|
*têtes de pomme de terre*.
|
|
|
|
Maybe I worry too much. If the glass is half empty, well, it's also half
|
|
full. Plainly, something I wrote inspired Melvyn to do something that is
|
|
wonderful, whether he realizes it or not. And it has been tremendously
|
|
gratifying to sense in the letters I have received the same feeling of
|
|
remarkably smart people going out there and doing amazing things just
|
|
for the sheer unadulterated fun of it.
|
|
|
|
I don't think I'm exaggerating too much (well, maybe a little) when I
|
|
say that this sort of fun is what I live for. I'm glad to see that so
|
|
many of you share that same passion.
|
|
|
|
Good luck. Thank you for your input, your code, and all your kind words.
|
|
Don't be afraid to attempt the impossible. Simply knowing what is
|
|
impossible is useful knowledge—and you may well find, in the wake of
|
|
some unexpected success, that not half of the things we call impossible
|
|
have any right at all to wear the label.
|
|
|
|
—Michael Abrash
|