plib-users

[Plib-users] Re: hotspots :-)

[Steve B. <sjb...@ai...>]

Ran...@ma... wrote:
> 
> You can either read all this stuff I've written below, or look at the
> following page (or both):
> 
> http://geography.bu.edu/brdf/brdfexpl.html

I know a *lot* about BRDF - that's what we try to implement using
Ambient/Diffuse/Specular/Emission on an OpenGL polygon - in the real
world, the way that light is scattered (both by smooth surfaces - and
surfaces with 'microtexture' like grass - or trees (if you are far enough
away).

I looked very hard at the photo's in that page - and I simply don't
see the "hotspot" he's talking about...

However, I think I understand what you are talking about (finally!)...

>  The easiest way to picture it in your mind is related to
> the phrase "The Sun sees no shadows."

So, let me get this straight.

What I *think* you are saying is that when the surface on the ground
has a sufficiently rough 'microtexture' such that it self-shadows,
there will be a place from which you can view that surface where
all the shadows are occluded by the micro-geometry that is casting
those shadows.  One such position is at the point where the light
source is being cast from...the sun which "sees no shadows". (More
or less - it sees shadows cast by other light sources of course).

So, if you are in a plane - looking down at the ground, your line
of sight to the microtexture will see those teeny-tiny shadows
everywhere *except* in the one special direction - at that point,
you are in a direct line between the ground and the sun - so you
see no shadows at all.  As you look off to the side of that spot,
you gradually see more and more shadow - so the ground is brightest
when your eye is in line with the sun.

COINCIDENTALLY - that is the *EXACT* spot where your shadow will
fall...but that's only a coincidence - all your earlier discussions
were throwing me off by saying it was due to some refractive or
angle of incidence effect.

So - this 'halo' or 'hotspot' isn't really related to the shadow,
it's a completely separate artifact.

Someone else - half a mile away - won't see any hotspot around
*your* shadow - they'll only see it around their own shadow.

In practical (OpenGL) terms...the hotspot occours when the angle
between the eye, the lightsource and the surface is nearly zero.

That's sortof like specular reflectance - except the surface
normal of the polygon is not involved.

I guess the simplest way to simulate that is to have a second
GL light source at the same location as the eye - but with a
narrow beam width - and pointing always away from the Sun.

You'd also only want this effect on very rough surfaces...the
effect would be invisible on smooth things like water.

That might not have an especially great physical resemblance to
the real thing - but it should do something that's "good enough".

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net
                         http://freeglut.sourceforge.net

Re: [Plib-users] Shadow

[<Ran...@ma...>]

http://geography.bu.edu/brdf/brdfexpl.html

I think the misunderstanding is because I didn't really make clear
that I am talking about the amount of illumination perceived by the
eye across the whole field of view.

As a thought experiment, place yourself on the line joining the sun
and the plate.  Notionally pick a spot behind the plate to target your 
eyes on.  Initially *no* shadow will be visible around the plate ("the 
sun sees no shadows").  Now move away from the line.  As you move
away, you see more and more shadow.  This effect integrated across all 
the shadow casting things gives the *apparent* increase in
brightness.  What is really happening is that you are merely seeing
less shadow around the shadow cast by the observer.  If you want to
dispense with the shadow cast by the observer (say the sun is doing
the observation), that's ok.  It still works.


The web-page explains it much better than I do/did.  My apologies for
the confusion, it wasn't intended.  If a means of generating the
phenomenon exists which is not too hard and not very CPU intensive
exists, it would be worth it.  It is one of those things that makes
"synthetic" images look really flat at lifeless (unless you are
simulating an overcast day).

Randall

Re: [Plib-users] Shadow

[Wolfram K. <w_...@rz...>]

Randall wrote:

>Real empirical science ... I can provide a few (old) references for
>those that are interested.

Yes, please do. I haven't heard of the effect. However, the opposite
is true: Just outside of the shadow, it is a bit darker. Ok, let me do
a Gedanken-experiment as well ;-):

You have a perfect, directed lightsource (parallel light), not a sun.
You have Steves metal plate a bit above the ground.=20

In first approximation, no direct light from the light source hits the
shadow and outside the sahdow the light intensity is 100%, that is,
its as high as it would be without the plate.=20

But if you are accurate, the light can slightly bend around objects
since it is a wave. You can see this effect on water waves and perhaps
remeber Huygens principle from school. This means, the parts of the
shadow close to the rim are light a bit. This light of course has to
come from somewhere, so just outside of the shadow you have less than
100%.=20

But, of course the physiolgical effect Steve spoke about (that
differences are exegarated by your eyes/brain) is much larger.

>Randall

Bye bye,
Wolfram.

Re: [Plib-users] Shadow

[Steve B. <sjb...@ai...>]

Ran...@ma... wrote:

> Dredging up the stuff from a previous incarnation, the "hotspot" isn't
> an optical illusion, rather it is related to the amount of visible
> shadow (cast by protruding objects on the surface) relative to the
> amount of visible, directly illuminated surface.

I don't understand where this 'extra' light comes from.

Please explain how light rays that would need to travel through
the solid object casting the shadow somehow bend around that
object to land on the ground in the halo region.

I can't conceive of a mechanism that would do that other than
at a microscopic scale.

> You are right -- the
> hotspot will appear without any additional code if the surfaces do in
> fact have a vertical texture (that was what my former incarnation
> depended on).  In my mind I was imagining that the the surfaces we
> were talking about were textured with texture maps, rather than
> something with real vertical texture.

You have me *completely* confused - how does "texture" have anything to
do with it?

Let's talk about a simple case.  I have a 1' square chunk of metal.
I hold it 3 feet above the ground at midday.  This will cast a 1' shadow
(roughly) with a dark 'umbra' in the center and will fade out to bright
sunlight over an inch or two through the 'penumbra' part of the shadow.

The edge of the shadow isn't 'hard' because the sun isn't a point
light source - and from a spot on the ground just on the edge of the
shadow, you only see (say) half of the sun's disk (the other half
being occluded by the metal plate).

You claim that the region just outside the penumbra will actually be
brighter than normal sunlight?

If yes - how does this extra light get there from the sun?  What
         geometrical path does it take?
If no - then please explain what's wrong with my experiment?

> It isn't an optical illusion -- you can use the size and intensity of
> the hotspot to elicit information from aerial photography about the
> size of (for example) trees in a stand and their mean distance apart.

I don't see how...

Hmmm - I think that this 'halo' you are talking about is just the
penumbra of the shadow...but if so, your description is very confused.

But even so, I don't see how using the width of the penumbra allows
you to deduce the height of trees in a photo if you didn't know
where the camera was relative to those trees...and if you know that
information then you don't need the penumbra (or any other shadow
information) to tell you that.

For an infinite light source (and the sun is pretty close to being
infinitely far away for these purposes :-) - the width of the
penumbra as measured on the ground depends only on the distance
between the shadow caster and the surface you are casting onto.
Generally, that doesn't help you determine the size of something
in a photo though. The top of 5 meter tree will be twice as close
to the ground as a 10 meter tree and therefore have a half-sized
penumbra.  Unfortunately, in the photograph, the penumbra's width
is affected by visual perspective - just like the tree.

Hence the shadow from a 10 meter tree photographed from 100 meters
up will look EXACTLY the same as a 5 meter tree from 50 meters up.
So examining the penumbra gives you no extra information that the
size of the tree on the photograph doesn't provide.

> Real empirical science ... I can provide a few (old) references for
> those that are interested.

Yes please!

Anyway, if you are talking about rendering the penumbra of an
aircraft's shadow, that's an easy thing.  Unless the plane is
**HUGE** or very close to the ground, it'll appear to be
smaller than the sun's disk when seen from the ground and the
shadow will be all penumbra and no umbra.  In that case, you
can just model a fuzzy shadow polygon and make it less and
less opaque as the height of the plane above the terrain
increases.  You *might* want to add a more solid 'umbra'
at low altitudes - but frankly, I wouldn't bother.  Most
people don't notice all this fancy scientific shadow stuff
and will be perfectly happy to see a fuzzy outline at all
altitudes.  That has the (LARGE) benefit that you don't have
to be too specific about the exact shape of the shadow - so
it doesn't have to change shape as the aircraft changes
orientation.

Doing *true* shadows in a general situation is *still* a bitch
of a problem...

Consider a moment just before sunset.  The sun is on the horizon.
The plane is flying low over very flat terrain.

The shadow of the plane stretches all the way to the horizon.
Because the terrain undulates, you'd have to cut up the shadow
polygon to fit it to the terrain surface - in realtime - at full
frame rates!  That's one heck of a lot of math!

There are some algorithms to use multipass textures that are
rendered on-the-fly by rendering the scene from the perspective
of the light source.  This takes one full scene render for each
shadow caster.  However, you don't know what resolution that
texture needs to be.  From the perspective of the sun, your
texture will have a nice sharp edge and will look good.  But
when you apply that to the terrain, it'll be far to coarse
in resolution for some eyepoints (eg when you are looking at
90 degrees to the sun's direction vector and you are close
to the ground).

There are NO good algorithms for general shadow casting.

Fortunately, the pragmatist will realise that humans don't
care.  We like to have a shadow to give a feeling of
the height of the object above the ground (especially when
close to the ground)...but if it's just a fuzzy cross-shape
then that's "good enough".

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net
                         http://freeglut.sourceforge.net

Re: [Plib-users] Shadow

[<Ran...@ma...>]

Steve Baker writes:
 > 
 > Ran...@ma... wrote:
 > 
 > NO!!!  You are seeing a 'mach band' which is an optical illusion that
 > will happen the same way in your program as it does in the real world
 > and doesn't have to be simulated.
 > 
 > There is no significant angle-of-incidence effect for most materials.

Dredging up the stuff from a previous incarnation, the "hotspot" isn't
an optical illusion, rather it is related to the amount of visible
shadow (cast by protruding objects on the surface) relative to the
amount of visible, directly illuminated surface.  You are right -- the
hotspot will appear without any additional code if the surfaces do in
fact have a vertical texture (that was what my former incarnation
depended on).  In my mind I was imagining that the the surfaces we
were talking about were textured with texture maps, rather than
something with real vertical texture.

It isn't an optical illusion -- you can use the size and intensity of
the hotspot to elicit information from aerial photography about the
size of (for example) trees in a stand and their mean distance apart.
Real empirical science ... I can provide a few (old) references for
those that are interested.

Randall

Re: [Plib-users] Shadow

[Steve B. <sjb...@ai...>]

Ran...@ma... wrote:
> 
> Michael Wessels writes:
> 
>  > in my flight simulator I like to introduce shadowing of the airplane to
>  > the ground.
>  > My question is , if anybody has experiences to do this in conjunction
>  > with using PLIB for the geometry presentation.
> 
> If anyone starts on this, they could try to model the "hotspot" which
> surrounds the shadow.  The lit ground/water/trees whatever are quite
> noticably brighter immediately around the shadow due to the angle of
> incidence and reflection.

NO!!!  You are seeing a 'mach band' which is an optical illusion that
will happen the same way in your program as it does in the real world
and doesn't have to be simulated.

There is no significant angle-of-incidence effect for most materials.

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net
                         http://freeglut.sourceforge.net

[Plib-users] Shadow

[<Ran...@ma...>]

Michael Wessels writes:

 > in my flight simulator I like to introduce shadowing of the airplane to
 > the ground.
 > My question is , if anybody has experiences to do this in conjunction
 > with using PLIB for the geometry presentation.


If anyone starts on this, they could try to model the "hotspot" which
surrounds the shadow.  The lit ground/water/trees whatever are quite
noticably brighter immediately around the shadow due to the angle of
incidence and reflection.  The size and intensity of the hotspot can
be related to the size and structure of the features on the ground.
The effect isn't as pronounced on surfaces such as snow and sand.

Occasionally you can notice it looking at your own shadow -- there
seems to be a halo around the head.  Very good for the ego.

Cheers!

Randall

[Plib-users] Shadow

[Michael W. <michael.wessels@z.zgs.de>]

Hi all,
in my flight simulator I like to introduce shadowing of the airplane to
the ground.
My question is , if anybody has experiences to do this in conjunction
with using PLIB for the geometry presentation.

Michael

Re: [Plib-users] Problems compiling plib-1.3.1

[Philipp F. <phi...@sw...>]

Hi Guido,

Am Fri, Feb 09, 2001 at 06:19:38PM +0100 hat Guido Aselmann getippert:
> I use debian (sid=unstable) with XFree86 Version 4.0.2 using the Module 
> nvidia: vendor="NVIDIA Corporation"

Why don't you use the package: plib1.3 and plib1.3-dev. They
compiled ok for me (I uploaded them :-)

Regards,
-- 
Philipp        work                    home
Frauenfelder   pfr...@ma...   pfr...@de...
[PGP]          +41 1 632 60 38         +41 1 862 73 14
Proudly running Debian GNU/Linux. See http://www.debian.org/

RE: [Plib-users] Problems compiling plib-1.3.1

[Norman V. <nh...@ca...>]

Guido Aselmann writes:
>
>tried to compile plib-1.3.1 and had the following problem
>./configure was okay 
>but 
>make fails with

do 
export GLUT_IS_PRESENT='1'

before you run configure or make

Hopefully this is fixed in the CVS sources
so that this is no longer necessary < hint >

Norman Vine

Re: [Plib-users] Problems compiling plib-1.3.1

[Wolfram K. <w_...@rz...>]

You asked:

>what libaries are missing ?

Your problem definitely has to do with glut.=20
Can you try to install that or check whether it is installed
correctly?

Bye bye,
Wolfram

[Plib-users] Problems compiling plib-1.3.1

[Guido A. <ase...@gm...>]

Hi,

tried to compile plib-1.3.1 and had the following problem
./configure was okay 
but 
make fails with

Making all in pui
make[2]: Entering directory `/home/guido/plib-1.3.1/src/pui'
c++ -DPACKAGE=\"plib\" -DVERSION=\"1.3.1\" -DHAVE_LIBDL=1 -DHAVE_LIBGL=1 
-DHAVE_LIBGLU=1 -DSTDC_HEADERS=1 -DHAVE_GL_GL_H=1 -DHAVE_GL_GLU_H=1 
-DLINUX_JOYSTICK_IS_PRESENT=1  -I. -I.  -I../../src/sg -I../../src/fnt 
-I../../src/util  -I/usr/local/include  -g -O2 -O6 -Wall -c pu.cxx
In file included from puLocal.h:2,
                 from pu.cxx:2:
pu.h: In method `puFont::puFont()':
pu.h:90: `GLUT_BITMAP_8_BY_13' undeclared (first use this function)
pu.h:90: (Each undeclared identifier is reported only once
pu.h:90: for each function it appears in.)
pu.cxx: In function `int puGetWindow()':
pu.cxx:42: implicit declaration of function `int glutGetWindow(...)'
pu.cxx: In function `int puGetWindowHeight()':
pu.cxx:49: `GLUT_WINDOW_HEIGHT' undeclared (first use this function)
pu.cxx:49: implicit declaration of function `int glutGet(...)'
pu.cxx:52: warning: control reaches end of non-void function 
`puGetWindowHeight()'
pu.cxx: In function `int puGetWindowWidth()':
pu.cxx:58: `GLUT_WINDOW_WIDTH' undeclared (first use this function)
pu.cxx:61: warning: control reaches end of non-void function 
`puGetWindowWidth()'
pu.cxx: In function `int puMouse(int, int, int, int)':
pu.cxx:331: `GLUT_DOWN' undeclared (first use this function)
pu.cxx: In function `int puMouse(int, int)':
pu.cxx:353: `GLUT_LEFT_BUTTON' undeclared (first use this function)
pu.cxx:354: `GLUT_MIDDLE_BUTTON' undeclared (first use this function)
pu.cxx:355: `GLUT_RIGHT_BUTTON' undeclared (first use this function)
make[2]: *** [pu.o] Error 1
make[2]: Leaving directory `/home/guido/plib-1.3.1/src/pui'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/guido/plib-1.3.1/src'
make: *** [all-recursive] Error 1

I use debian (sid=unstable) with XFree86 Version 4.0.2 using the Module 
nvidia: vendor="NVIDIA Corporation"

I can run OpenGL stuff like MESA Gear sample or Specs Viewperf

> dpkg -S gl.h   shows
qt2.2-doc: /usr/share/doc/qt2.2-doc/doc/html/qgl.html
xlibmesa-dev: /usr/include/GL/gl.h
qt2.2-doc: /usr/share/doc/qt2.2-doc/doc/html/opengl.html
libqt2.2-dev: /usr/include/qt/qgl.h
glutg3-dev: /usr/include/GL/fgl.h

what libaries are missing ?


-- 
Sent through GMX FreeMail - http://www.gmx.net

Re: [Plib-users] PLib Tutorials

[Wolfram K. <w_...@rz...>]

We don't have a real tutroial, but we have the examples and we have a
almost 100% complete doc for users of plib (developers of games/apps
that use plib) at

plib.sourceforge.net

Click on the name of the sub-library you are interested in.
BTW, if you have any comments about the docs (for ex. regarding
errors, inclusive spelling or grammar errors, hard to understand
things, missing things etc), please mail here.=20

Bye bye,
Wolfram.

[Plib-users] PLib Tutorials

[Tony O'B. <sto...@ax...>]

Are there any tutorials on the web for PLib?  I couldn't find any usage 
docs (aside from ssgInit() being the first ssg call) on the main PLib 
Sourceforge page.
-- 
I filter out all hotmail messages because hotmail is one of the worst
spamming offenders.  If I sent this to your hotmail address, you must
reply using a different email account or my filter will automatically
trash your message.

Re: [Plib-users] config.h

[Sam S. <sa...@sp...>]

----- Original Message ----- 
From: "Norman Vine" <nh...@ca...>
To: <pli...@li...>
Sent: Monday, January 22, 2001 5:37 PM
Subject: RE: [Plib-users] config.h


> Sam Stickland writes:
> 
> >Norman Vine wrote:"
> >> >
> >> >I thought the Windoze compilers did that automatically.
> >> 
> >> AFAIK all Windows compilers define _WIN32 < notice underbar >
> >> 
> >
> >Well I just checked MSVC++ and it makes these preprocessor definations
> >
> >WIN32,_DEBUG,_CONSOLE,_MBCS
> >
> >Notice that the WIN32 has no underscore?  What a pain...
> 
> Sam could you please try this simple test program

Well that will teach me to post without checking first :)

_WIN32 found
WIN32 found

Opps.

Sam

RE: [Plib-users] config.h

[Norman V. <nh...@ca...>]

Sam Stickland writes:

>Norman Vine wrote:"
>> >
>> >I thought the Windoze compilers did that automatically.
>> 
>> AFAIK all Windows compilers define _WIN32 < notice underbar >
>> 
>
>Well I just checked MSVC++ and it makes these preprocessor definations
>
>WIN32,_DEBUG,_CONSOLE,_MBCS
>
>Notice that the WIN32 has no underscore?  What a pain...

Sam could you please try this simple test program

-------------

#include <stdio.h>

int main( int argc, char **argv )
{
#ifdef _WIN32
	printf("_WIN32 found\n");
#endif
#ifdef WIN32 
	printf("WIN32 found\n");
#endif
#if !defined( _WIN32 ) && !defined( WIN32 )
	printf("Neither _WIN32 or WIN32 found\n");
#endif
	return 0;
}

Re: [Plib-users] config.h

[Sam S. <sa...@sp...>]

----- Original Message ----- 
From: "Norman Vine" <nh...@ca...>
To: <pli...@li...>
Sent: Sunday, January 21, 2001 5:43 PM
Subject: [Plib-users] config.h


> < changing the subject header for archival purposes >
>    was   'RE: [Plib-users] joystick library'
> 
> Steve Baker writes:
> >
> >Norman Vine wrote:
> >
> >> This should make a my_js_dem0.exe
> >> c++ -o my_js_demo -DWIN32 js_demo.cxx -lwinmm -lplibul
> >> 
> >> I do not like having to define WIN32  to make this work
> >
> >I thought the Windoze compilers did that automatically.
> 
> AFAIK all Windows compilers define _WIN32 < notice underbar >
> 
> PLib using WIN32 is I believe a carryover from the FlightGear world.
> When they started using it I do not know < before I arrived though >

Well I just checked MSVC++ and it makes these preprocessor definations

WIN32,_DEBUG,_CONSOLE,_MBCS

Notice that the WIN32 has no underscore?  What a pain...

Guess the config.h file would have to have something like:

#if defined(_WIN32) && !defined(WIN32)
    #define WIN32
#endif

?

Sam

Re: [Plib-users] config.h

[Sam S. <sa...@sp...>]

----- Original Message ----- 
From: "Norman Vine" <nh...@ca...>
To: <pli...@li...>
Sent: Sunday, January 21, 2001 5:43 PM
Subject: [Plib-users] config.h


> < changing the subject header for archival purposes >
>    was   'RE: [Plib-users] joystick library'
> 
> Steve Baker writes:
> >
> >Norman Vine wrote:
> >
> >> This should make a my_js_dem0.exe
> >> c++ -o my_js_demo -DWIN32 js_demo.cxx -lwinmm -lplibul
> >> 
> >> I do not like having to define WIN32  to make this work
> >
> >I thought the Windoze compilers did that automatically.
> 
> AFAIK all Windows compilers define _WIN32 < notice underbar >
> 
> PLib using WIN32 is I believe a carryover from the FlightGear world.
> When they started using it I do not know < before I arrived though >

Well I just checked MSVC++ and it makes these preprocessor definations

WIN32,_DEBUG,_CONSOLE,_MBCS

Notice that the WIN32 has no underscore?  What a pain...

Guess the config.h file would have to have something like:

#if defined(_WIN32) && !defined(WIN32)
    #define WIN32
#endif

?

Sam

Re: [Plib-users] config.h

[Wolfram K. <w_...@rz...>]

Norman wrote:

>We could go through the code and change all WIN32 to _WIN32
>[...]
>Any comments anyone on my just doing this ???

Sounds good.

>>> What do folks think of having the  make install  command
>>> create a <plib/config.h> that contains the -Defines used when plib =
was
>>> compiled
>>> <plib/config.h> would then be include by our other headers
>>
>>Sure - that's something that autoconf is able to do...I forget how
>>exactly...
>
>I think it is fairly easy todo but I have never done it.
>Have we got amy autoconfig gurus on the list ?

But I would guess that running make calls the compiler with include
path and other options set. You can only have defines and not compiler
options in the config.h. So, if I see things correctly, when someone
does a new project under Cygwin or Linux, he would still have to think
about doing autoconf stuff / a manual makefile or batch file
containing the correct settings for his system.=20


>Cheers
>
>Norman Vine=20

Bye bye,
Wolfram.

[Plib-users] config.h

[Norman V. <nh...@ca...>]

< changing the subject header for archival purposes >
   was   'RE: [Plib-users] joystick library'

Steve Baker writes:
>
>Norman Vine wrote:
>
>> This should make a my_js_dem0.exe
>> c++ -o my_js_demo -DWIN32 js_demo.cxx -lwinmm -lplibul
>> 
>> I do not like having to define WIN32  to make this work
>
>I thought the Windoze compilers did that automatically.

AFAIK all Windows compilers define _WIN32 < notice underbar >

PLib using WIN32 is I believe a carryover from the FlightGear world.
When they started using it I do not know < before I arrived though >

We could go through the code and change all WIN32 to _WIN32
and see if that worked.  We of course would still have the occasional

#if defined(_WIN32) && !defined(__CYGWIN__)
where we really want Unix behaviour when using Cygwin

Any comments anyone on my just doing this ???

>> What do folks think of having the  make install  command
>> create a <plib/config.h> that contains the -Defines used when plib was
>> compiled
>> <plib/config.h> would then be include by our other headers
>
>Sure - that's something that autoconf is able to do...I forget how
>exactly...

I think it is fairly easy todo but I have never done it.
Have we got amy autoconfig gurus on the list ?

Cheers

Norman Vine 

Re: [Plib-users] joystick library

[Steve B. <sjb...@ai...>]

Norman Vine wrote:

> This should make a my_js_dem0.exe
> c++ -o my_js_demo -DWIN32 js_demo.cxx -lwinmm -lplibul
> 
> I do not like having to define WIN32  to make this work

I thought the Windoze compilers did that automatically.
 
> What do folks think of having the  make install  command
> create a <plib/config.h> that contains the -Defines used when plib was
> compiled
> <plib/config.h> would then be include by our other headers

Sure - that's something that autoconf is able to do...I forget how
exactly...
 
-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net
                         http://freeglut.sourceforge.net

RE: [Plib-users] joystick library

[Norman V. <nh...@ca...>]

Steve Baker writes:
>
>McCracken Ryan wrote:
>
>> I figured I might try running js_demo.cxx on my own to
>> see if it was my code. So I type this:
>>
>> g++ js_demo.cxx
>>
>> The executable appears by default in a.exe. I run it
>> and the controllers still don't work. So if the code
>> that created js_demo.exe is js_demo.cxx, is there some
>> sort of option that I'm missing to get an executable
>> that works like the js_demo.exe? Or is the problem
>> more serious/complicated?
>
>Hmmm - I'm a little suprised that something as simple
>as:
>
>g++ js_demo.cxx
>
>...would compile correctly - but since the JS stuff is just
>a single header file - I suppose it could work.

This should make a my_js_dem0.exe
c++ -o my_js_demo -DWIN32 js_demo.cxx -lwinmm -lplibul

I do not like having to define WIN32  to make this work

What do folks think of having the  make install  command
create a <plib/config.h> that contains the -Defines used when plib was
compiled
<plib/config.h> would then be include by our other headers

Norman Vine

Re: [Plib-users] joystick library

[Steve B. <sjb...@ai...>]

McCracken Ryan wrote:

> OK, running Windows '98 (try not to hate me too much
> for doing this).

I'm *trying*...but it's not going to be easy.

> I installed Cygwin and it seems to
> work quite well.

You have Cygwin - well, that's improved your
credibility *slightly*. :-)

> I downloaded the plib stuff (1.3.1).
> I did what the readme told me to:
> 
>   ./configure
>   make
>   make install

Excellent.
 
> OK, so now I have the example js_demo.cxx file in
> /usr/local/plib_examples-1.3.1/src/js
> 
> In this directory there is also a file called
> 'js_demo.exe'. So I type './js_demo', and -Eureka!- it
> works for both of my controllers.

Woohoo!
 
> But now I decide to try running some of my own stuff.
> There is a problem at the point at which the statement
> js[0]->notWorking () appears. This statement returns a
> value of 1 (not working).

Not good.
 
> I attached the js_demo.cxx code for ease of viewing.
> 
> I figured I might try running js_demo.cxx on my own to
> see if it was my code. So I type this:
> 
> g++ js_demo.cxx
>
> The executable appears by default in a.exe. I run it
> and the controllers still don't work. So if the code
> that created js_demo.exe is js_demo.cxx, is there some
> sort of option that I'm missing to get an executable
> that works like the js_demo.exe? Or is the problem
> more serious/complicated?

Hmmm - I'm a little suprised that something as simple
as:

g++ js_demo.cxx

...would compile correctly - but since the JS stuff is just
a single header file - I suppose it could work.

However, the PLIB distro doesn't come with binaries or
executables of any kind - so js_demo.cxx *did* compile on
your setup...but with a different compile line.

I suggest you 'touch js_demo.cxx' - to change the date on it,
then re-run the 'make' for the top level 'examples' directory.

That should cause it to recompile js_demo.exe - and (importantly),
you'll see what commands it used to compile it.  I can't predict
what those will need to be because the 'configure' script generates
the Makefile's specifically to suit your machine's setup.

I'm guessing that there should be something like "-DCYGWIN=1" on the
compile command line.  Without that, it's probably compiling the set of
commands that would work under Linux rather than the ones for Windoze/Cygwin.
However, I havn't used Windoze for over 10 years...so my advice may
be worth nothing!

Perhaps someone on this list who uses CygWin will be able to offer
more help.

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net
                         http://freeglut.sourceforge.net

[Plib-users] joystick library

[McCracken R. <inf...@ya...>]

Hey, I'm trying to break free of the classroom
dependencies inflicted on me (college experiences).
So, here goes my first question (hopefully not too
naive - the subject matter in the archive is pretty
intimidating):

OK, running Windows '98 (try not to hate me too much
for doing this). I installed Cygwin and it seems to
work quite well. I downloaded the plib stuff (1.3.1).
I did what the readme told me to:

  ./configure
  make
  make install

OK, so now I have the example js_demo.cxx file in
/usr/local/plib_examples-1.3.1/src/js

In this directory there is also a file called
'js_demo.exe'. So I type './js_demo', and -Eureka!- it
works for both of my controllers.

But now I decide to try running some of my own stuff.
There is a problem at the point at which the statement
js[0]->notWorking () appears. This statement returns a
value of 1 (not working).

I attached the js_demo.cxx code for ease of viewing.

I figured I might try running js_demo.cxx on my own to
see if it was my code. So I type this:

g++ js_demo.cxx

The executable appears by default in a.exe. I run it
and the controllers still don't work. So if the code
that created js_demo.exe is js_demo.cxx, is there some
sort of option that I'm missing to get an executable
that works like the js_demo.exe? Or is the problem
more serious/complicated?

Any help would be GREATLY appreciated.

Thanks,
/R

__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - Buy the things you want at great prices. 
http://auctions.yahoo.com/

[Plib-users] questions about collision detection and writing loaders

[<cal...@ya...>]

i have two questions :
1- what are the best methods plib provides for
collision detection( for accuracy, performance etc..)?
will it support sweep tests for solids?

2-what is the best method for creating our own
geometry? I am writing a FLT loader fow plib and want
to ensure that the hierarchy i created could be
rendered fast.

__________________________________________________
Do You Yahoo!?
Get email at your own domain with Yahoo! Mail. 
http://personal.mail.yahoo.com/