From: Nate Eldredge <neldredge AT hmc DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Projectile Bouncing off walls
Date: 21 Jan 2000 16:59:33 -0800
Organization: InterWorld Communications
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Sahab Yazdani <beyonder69 AT geocities DOT com> writes:

> Hello I have written a simple trajectory calcutation system using
> Velocity, Angle, wind and gravity. Now lets say I want to make the
> projectile bounce off the wall.. How would I go about doing this???
> heres the code that I have right now:

Simplest way is to let the angle of incidence equal the angle of
reflection.  Define a normal N, a line perpendicular to the wall at
the point of impact.  The angle between the projectile and N as it
enters (angle of incidence, Ti) should be equal to the angle as it
leaves (angle of reflection, Tr).  Picture:

                   O    |
                    \   |
                  /--\  |
                 /    \ |
                Ti     \|
         N-------------->
                Tr     /|
                 \    / |
                  \--/  |
                    /   |
                   V    |

-- 

Nate Eldredge
neldredge AT hmc DOT edu