[PyOpenGL-Devel] [ pyopengl-Bugs-1920052 ] glMultMatrixf ignores array transpose

[SourceForge.net <no...@so...>]

Bugs item #1920052, was opened at 2008-03-19 15:11
Message generated for change (Comment added) made by mcfletch
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105988&aid=1920052&group_id=5988

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: v3.0.0
Status: Open
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: glMultMatrixf ignores array transpose

Initial Comment:
glMultMatrixf ignores transpose operations applied to matrices. presumably transpose just sets a bit and doesn't change the array in memory? 

is there a workaround other than transposing the matrix by hand in python?

I am running pyopengl version 3.0.0a6 on with python 2.5.1 on ubuntu 7.10.

in the following code fragment I create an identity matrix, set the x offset to be 20 and then transpose it before feeding it to glMultMatrixf. the glMultMatrixf call seems to ignore the preceding transpose operation:
[code]
m = glGetFloatv( GL_MODELVIEW_MATRIX )
print "matrix before multiply:\n%s" % str(m)

t = eye(4)
t[3,0] = 20.0
print "transform matrix before transpose:\n%s" % str(t)

# the following glMultMatrixf call ignores this transpose
t = t.T
print "multiplying with transform matrix:\n%s" % str(t)
 
glMultMatrixf( t )

m = glGetFloatv( GL_MODELVIEW_MATRIX )
print "matrix after multiply:\n%s\n\n" % str(m)
[/code]

output:
[code]
matrix before multiply:
[[   1.    0.    0.    0.]
 [   0.    1.    0.    0.]
 [   0.    0.    1.    0.]
 [   0.    0. -603.    1.]]
transform matrix before transpose:
[[  1.   0.   0.   0.]
 [  0.   1.   0.   0.]
 [  0.   0.   1.   0.]
 [ 20.   0.   0.   1.]]
multiplying with transform matrix:
[[  1.   0.   0.  20.]
 [  0.   1.   0.   0.]
 [  0.   0.   1.   0.]
 [  0.   0.   0.   1.]]
matrix after multiply:
[[   1.    0.    0.    0.]
 [   0.    1.    0.    0.]
 [   0.    0.    1.    0.]
 [  20.    0. -603.    1.]]
[/code]

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

>Comment By: Mike C. Fletcher (mcfletch)
Date: 2008-04-18 16:34

Message:
Logged In: YES 
user_id=34901
Originator: NO

This appears to be fixed in current CVS.

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

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105988&aid=1920052&group_id=5988