[comp.sys.sgi] GL error. What does it mean?

marcc@yoyodyne.ncsa.uiuc.edu (Marc Cooper) (01/31/91)

I'm getting the following error from my program, which continues to run,
but doesn't perform as expected..

ERROR #1  gl_invert4d :  ERR_SINGMATRIX


My first throught is that somehow I'm passing in a non-invertible matrix,
but that seems rather difficult, since the only time I use loadmatrrix()
is with a predefined 4x4 identity matrix.  

Any details on exactly what this error is and possible causes/fixes are
appreciated.  Replys though here or email are fine...

--
Marc Cooper		| "In my childhood, I WAS an imaginary playmate."
marcc@ncsa.uiuc.edu	|	-Tom Robbins, EVEN GOWGIRLS GET THE BLUES

		National Center for Supercomputing Applications

Disclaimer:	"It's mine! All mine!"  -D. Duck

andreess@mrlaxs.mrl.uiuc.edu (Marc Andreessen) (01/31/91)

In article <1991Jan30.161544.7845@ux1.cso.uiuc.edu> marcc@yoyodyne.ncsa.uiuc.edu (Marc Cooper) writes:
>I'm getting the following error from my program, which continues to run,
>but doesn't perform as expected..
>
>ERROR #1  gl_invert4d :  ERR_SINGMATRIX

One generally sure way of getting errors like this is scaling some
dimension to 0... which is easy to do accidentally - i.e. doing
scale( 0., 0., z_factor ) instead of scale( 1., 1., z_factor ).

Check all transformations several times over - it's probably a source code
bug.

Marc

--
Marc Andreessen___________University of Illinois Materials Research Laboratory
Internet: andreessen@uimrl7.mrl.uiuc.edu____________Bitnet: andreessen@uiucmrl