[plt-scheme] v300, my notes

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Mon Jan 2 23:03:08 EST 2006

At Mon, 2 Jan 2006 14:11:53 +0100 (CET), Ivanyi Peter wrote:
> - [...] This is the
> fourth version of glSelectBuffer that I see; guile, bigloo
> and others do it differently.

I'll leave this one to Scott.

> - As the case sensitivity is introduced I have noticed a
> strange thing. In DrScheme when I select the "Pretty Big"
> Language or similar and I do not switch on the case
> sensitivity then it is impossible to call OpenGL functions.
> For example after: (require (lib "gl.ss" "sgl")) and typing
> glbegin DrScheme reports an error. When case sensitivity is
> switched on glBegin is OK. Is this behaviour documented
> anywhere? Is it normal?

If I understand, then it's normal. In case-insensitive code, `glBegin'
represents the identifier `glbegin', which means that it won't refer to
a binding whose name is really `glBegin'.

I've added a note to the docs for "gl.ss" to explicitly state that the
names are case-sensitive, and therefore difficult to access in
case-insensitive code. (The more Scheme-ish "sgl.ss" downcases all
names, of course.)

> - Run the following Scheme snippet in DrScheme and you will
> notice that the line of the boxed panel crosses the button.

I haven't been able to reproduce this behavior on any of my X displays,
and I suspect that it has something to do with fonts. Can you tell me
about the fonts on your system?

> - There is an important (at least to me) difference in the
> appearance of the button in Windows and Linux. In Windows
> there is no border while in Linux there is a 2 or more pixel
> border. This means that in Linux the buttons are spaced
> further away from each other and they do not look so neat.
> Is there a way to get rid of the border in Linux?

Similar space exists in Windows for the more modern XP controls,
instead of the "Classic" controls. (And Mac OS X has even more space,
since everything is bigger and more widely spaced on the Mac.)

If you want a set of tightly spaced buttons, then you probably want a
different control --- maybe like the toolbar for the GUI builder?

> - My last note is again Linux related. [...]
> If I run the following "gl-base.scm" OpenGL program in
> DrScheme twice, then DrScheme crashes for the second time
> with Segmentation Fault. [...] And there is a
> second problem with it that even when I run it for the first
> time it does not display anything only a white background.

This one also works for me. I expect that MrEd is not cooperating right
with your GL driver, and the problem is likely with either the creation
of the GL context or with context selection. Let's take this part

Thanks for the feedback,

Posted on the users mailing list.