Talk:Ray casting

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This page doesn't describe ray casting - it describes an application of ray casting used in old video games (DOOM specifically). Should be rewritten to describe ray casting in general.

There's already a good article on ray casting in general, so I've tried to alter this article to reflect the situations where the term ray casting is more common. I hope I've made a significant advancement. ThomasHarte 21:04, 12 August 2005 (UTC)

Contents

[edit] New edit 11/18/2005

This page incorrectly defines ray casting as a synonym for ray tracing and cites extremely outdated examples of its implementation. While the old implementation might be useful as a foray into the beginnings of real-time video games, it gives the wrong impression of the current state of rendering technologies used in real-time games. I added the ray casting info from the ray tracing definition, because I come to WIkipedia for definitions, not examples - so hopefully I am not alone! It would be nice to add some links and data about the current uses of Ray tracing.

K.C. Murphy


I agree. This article also needs restructuring. Ray casting is activly used e.g. in direct volume visualisation (medical/scientific visualisation).

[edit] Flash raycasting

At first, I was going to edit this because it was non-neutral, but, considering it......

  • was non-notable
  • violates copyright (I believe Wolfenstein's engine is free for use, its graphics aren't)
  • is a thinly veiled advertisement for a "consolidation loan"
  • is probably a vanity edit

.....I removed it altogether. The sections above it talk about major engines' use of raycasting. This, however, was just some dude's little flash project. It doesn't follow from the other sections, it's not useful, it's not even interesting: There are a million raycasting engines, this makes it a million and one. Now that Flash 8 allows pixel-level manipulation of images, it's practically trivial task, no more difficult than any other implementation and therefore not more significant than any other: congratulations on your mediocrity.

With the above reasons, then, it needs to go. so it did. TheBilly 13:19, 23 April 2006 (UTC)

[edit] Origin of term "ray casting"

I'm certain that I first used the term "ray casting" in my published paper:

Roth, S. D. "Ray Casting for Modeling Solids." Computer Graphics and Image Processing, 18 (February 1982), 109-144.

"Computer Graphics" by Foley, et al, references my paper. The paper describes the use of rays to model solids and to generate images of solid compositions using shadows, transparancy, etc. The paper includes numerous computer-generated examples.

I guess it would ve vain of me to edit aritcle.

-- Scott Roth

[edit] Duke3D

The section on how duke nukem 3D is made is wrong, commented by the engine devloper: http://jonof.edgenetwork.org/forum/viewtopic.php?p=7012#7012

I propose that the section be either removed or corrected. I'll remove it for now.

-I corrected it --24.56.241.134 21:21, 6 March 2007 (UTC)

[edit] Doom uses "trigonometric multiply" instead of division??

So Doom has a BSP that is used to reduce the number of walls available for raycasting and speed up the process. According to the article, "This has the advantage of replacing thousands of expensive divide operations with trigonometric multiplies." But what is a trigonometric multiply? —Preceding unsigned comment added by 136.176.8.18 (talk) 15:10, 4 September 2007 (UTC)

  • I want to know, too. I think it has to do with multiplying x*z and y*z instead of dividing x/z and y/z for 3d to 2d projection. This also enables the use of integers instead of floating points. The integer can then be split up into levels of accuracy (like in a fixed point). Is there an article specifically on this topic of multiply vs. division for projection, or even a more proper term than "trigonometric multiply"? Each choice has its advantage, and (as far as I know) division wins out. Erudecorp ? * 23:11, 22 October 2007 (UTC)
  • I removed the Doom section since I couldn't find any evidence that Doom used ray casting at all. JustinTalbot (talk) 00:36, 22 November 2007 (UTC)