Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!goanna!minyos!godzilla!mg
From: mg@ (Mike Gigante)
Newsgroups: comp.sys.sgi
Subject: Re: libsphere - how do I get a sphere into an object?
Message-ID: <mg.657942703@godzilla>
Date: 7 Nov 90 01:51:43 GMT
References: <10445@milton.u.washington.edu> <1990Nov5.163639.12230@odin.corp.sgi.com>
Sender: news@minyos.xx.rmit.oz.au
Distribution: comp.sys.sgi
Lines: 39

kurt@cashew.asd.sgi.com (Kurt Akeley) writes:

]In article <10445@milton.u.washington.edu>,
]merritt@milton.u.washington.edu (Ethan Merritt) writes:
]|> I.e.:
]|> 	sphobj( sphere_object );
]|> 	makeobj( spheres );
]|> 	for (i = 0; i < nspheres; i++ )
]|> 		{
]|> 		move( &xyz[i] );
]|> 		callobj( sphere_object );
]|> 		}
]|> 	closeobj();
]|> 	callobj( spheres );
]|> doesn't seem to do anything other than pile up spheres on top of each other.
]|> 

]You're almost there, but you dropped the ball by calling move() to reposition
]the spheres.  The way to reposition any GL object, including the sphere
]objects, is to redefine the object-to-eye coordinate transformation by calling
]translate().  Just replace your move() call with a translate() call and things
]should work well.

]-- kurt

You probably want
	{
	pushmatrix();
	translate(x, y, z);
	callobj( .. );
	popmatrix();
	}

i.e. wrap a push/pop matrix pair around the translate/callobj,
otherwise each transform will be accumulated with the previous
transforms..  (that is asuming that the x,x,z correspond to the "world
coordinate" position of the spheres)

Mike Gigante, RMIT Australia