geometry-challenged

[Jim Hurley]

>
>on Tue, 27 Jan 2004 04:48:23 -0800
>Jim Hurley wrote:
>
>>  I put up an application using the "intersection"
>>  function which does something quite similar to
>>  this on my web site some time ago. It was
>>  a response to a question on the list about colliding
>>  polygons. You can drag or propel one polygon
>>  to/at another. They beep or bounce off
>>  one another when any line of one polygon intersect
>>  any  line of the other.
>>
>>  See "Colliding Polygons" at
>>  http://home.infostations.net/jhurley/
>
>Thanks a lot Jim! I bookmarked your website.
>
>I'll look closely a this function.
>
>Did you noticed that some files does not have
>an extension like: .rev or .mc or .txt?
>
>In this page, you have your excellent work with
>Turtle graphics.
>Do you have plans for an electronic edition of
>your book on Turtle graphics?
>You can do it all within Rev. Lessons and exercises.
>
>Keep Up your good work!
>
>al


Al,

Thank you for the kind words. Promoting TG can be lonely work.

I keep forgetting the PC world. I presume these suffixes are a 
necessity there. I have added the appropriate appendages.

I also updated the Colliding Polygons. No end of difficulties there. 
I want to be able to include the possibility of the (colliding) 
graphic objects being rectangles. In this case it is a challenge 
finding the intersection of all those parallel lines :-) (I fake it 
by altering slightly the coordinates. This allows for the detection 
of two parallel line segments when they are touching. It is only in 
this feature that my "intersection" function differs from that of 
Trevor. His function returns "empty" for parallel lines. Certainly 
his function is easier to read and understand and can easily be 
modified to deal with rectangles.)

I gave a (electronic) copy  of my Turtle Graphics book to RR. It 
really isn't what they are looking for in an introduction to 
programming. Their objective is programming for programmers; mine is 
programming for science students.

I'm not sure what you mean by "You can do it all within Rev. Lessons 
and exercises."

I have a (popular) physics book coming out dealing with the second 
law of thermodynamics and the time-asymmetry paradox. I am doing some 
work constructing stacks to put on the book's web site. They will be 
interactive illustrations of some of the physics discussed in the 
book. I am enjoying the challenge. And thank God for RR. Impossible 
with this incredible tool. (Also--shameless plug--impossible with the 
TG addendum to Transcript. Although TG is perceived simply as an 
educational tool, it is also an indispensable graphics tool.)

  Jim