Warp wrote:

>   What in the image makes you (and 90% of other people as well) think
> that that image has something to do with perspective? I can't understand
> it.
>   There's no perspective nowhere in the drawings. It's purely 2D.

Oh well, so I misinterpreted the drawings. Anyway, IMHO that particular 
kind of transformation does imply a perspective; it provides an important 
visual cue, as is seen in various illusions, such as here:

http://www.optillusions.com/dp/files/1-36.gif

And, although it is of course possible to map a texture like that, I'm not 
sure how common or useful it is. 

>   And even if there would be perspective there (which there isn't), why
> would lack of perspective correction cause the artifact depicted there?

Well, a triangle texture mapper without perspective correction interpolates 
linearly both in screen space and in texture space, and produces the 
artifact. This obviously isn't how perspective works - to produce the 
correct output, the mapper needs to interpolate inlinearly based on the 
triangle vertices' z coordinates. The artifact can be clearly seen in some 
old games such as Tomb Raider 2 or I-War, when run with software rendering.

Post a reply to this message