Inferno #05 30 апреля 2004

Программирование

For Coderz - Nuances Raycasting-a.

Raycasting note


   Article Shiru Otaku pro reykasting was
removed from the unpublished material
Adventurer # 14. In accordance with the traditions of our 
publication (or rather, his Guide-part;), it also features my 
remarks. Naturally, my opinion is not true

of last resort. By the way, this material, laced with enough 
personal misunderstanding on the part of the lecturers, taught 
on the course "Computer Graphics" in the area third-year 
specialty software providing something something and something 
something. "Spektrumistam study at university to I do not 
advise this specialty. 


   Initially, the article contained an opinion
that the character can not rotate on an axis perpendicular to 
the screen. Here's how: 



   However, my part, I believe that
possible. To do this, build a picture, though the hero does not 
revolved around this axis, and then transfer the image onto the 
screen in the rotated form.



   Of course, this can rarely be necessary,
but suddenly? In the demo, for example ...



   Wall at 45 ° (ie, NE to SW or NW
on the SE) can be realized in the standard
reykastinge, and in my version, where a continuous scan. In the 
second case it otniet not so much CPU time, but This number 
teoreticheski.Poskolku the scan will be very difficult. At the 
entrance in each block to check whether there

diagonal wall, and if so, what -
according to its type must occur
transition to the desired option of the inner loop. In 
processing the diagonal options one of the coordinates to be 
distorted: X = X + Y, or X = XY, or Y = X + Y, or Y = XY, in

Depending on the type of wall and directions
entrance to the cube. The same should be done with variables 
that contain step. Then the cycle will work as usual, 
t.e.slozhenie with access to overflow. 



   Actually, the standard reykastinge,
if the type of dice to the wall to know in advance
the rate of fall was not a factor of 2. But the algorithm seems 
even wiser. 


                               Alone Coder