[Mesa3d-dev] [ mesa3d-Bugs-429312 ] glMaterialfv broken with Translucency

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Bugs item #429312, was opened at 2001-06-01 07:19
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Category: mesa-core
Group: Rendering Error
Status: Open
Resolution: None
Priority: 5
Submitted By: Michael Saunders (rms7326)
Assigned to: Nobody/Anonymous (nobody)
Summary: glMaterialfv broken with Translucency

Initial Comment:
The glMaterialfv function does not seem to recognize
changes to translucency correctly. We are pulling
"panels" off of a depth sorted panel heap and then then
setting the appropriate translucency for each. The
order of our OpenGL calls looks something like this:


glNewList(dataList, GL_COMPILE)
glDepthMask(FALSE)
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
glPolygonMode(GL_FRONT_AND_BACK, 6914)
glEnable(GL_LIGHTING)
glShadeModel(GL_FLAT)
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE,
RGBA_array) where RGBA_array[0..3]=[0.823529,0,0,0.9]
glBegin(GL_POLYGON)
glNormal3d(0 1 0)
glVertex3d(1.1,0,0)
glVertex3d(1.1,0,1)
glVertex3d(2.1,0,1)
glVertex3d(2.1,0,0)
glEnd()
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE,
RGBA_array) where RGBA_array[0..3]=[0.823529,0,0,0.5]
glBegin(GL_POLYGON)
glNormal3d(0 1 0)
glVertex3d(0,0,0)
glVertex3d(0,0,1)
glVertex3d(1,0,1)
glVertex3d(1,0,0)
glEnd()
glDepthMask(TRUE)
glDisable(GL_BLEND)
glEndList()
glCallList(dataList)
glFlush()

What we discover is that the two polygons have the same
instead of different translucency. This is a small
example of a larger problem. When we draw tens of
thousands of polygons in this way we discover that on
occasion the correct translucency value is pushed
through, almost as if there is a cache problem. I know
it is not graphics card related cache problem because
we have run the Mesa version of our product on various
platforms all exhibiting the same behavior.

Additionally, we are using Mesa 3.4.1. I can provide
more info about what we are doing before and after the
above calls if needed.

Thanks,
Michael

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>Comment By: Michael Saunders (rms7326)
Date: 2001-07-16 17:42

Message:
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Brian,

I got a chance to check out the 3.5 release and the problem
with glMateral is now fixed so you can close this bug
report. I did however discover another bug with
glColorMaterial and strips which I will report separately.

Michael

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

Comment By: Brian Paul (brianp)
Date: 2001-06-04 09:01

Message:
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user_id=983

I think this should be fixed in Mesa 3.5 (the CVS trunk). 
Can you
give that a try?



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