Hi Jonathan,
We basically just told Nuke to draw Polygons or Points, and didn't try
to set
any OpenGL state using gl calls in our plugins. Nuke must have done that
behind
the scenes when drawing polygons. Is there any way to know exactly what
OpenGL
states Nuke has changed?
Thanks a lot,
-Jean
Qin Shen wrote:
Hi Jonathan,
Thanks a lot for the tip! I'll give it a try.
-Jean
Jonathan Egstad wrote:
I need to see the points, so I set the Group_Points attribute "Cf" and
fill in the Vector4 values with my RGBA. All seems to be good if I
don't switch away from displaying Point primitive mode.
However, I need to toggle between two modes, the regular Polygon
primitive mode or the Point primitive mode. Once I toggle to Polygon
mode and come back to Point mode, the displayed points totally go crazy.
Not only does the color start to be random, the number of points
displayed
also goes wacky. Each time a random set of points will be missing.
You're referring to the OpenGL display of Point primitives, correct?
Not the render output?
Likely the OpenGL state is being left in a bad state from a previous
object's drawing. Because the order in which objects are drawn can
change depending on how the user is interacting with the Viewer this
can cause what you're seeing - random display problems.
One of the aggravations of the OpenGL state engine is needing to set
all sorts of parameters just in case it's been set by other code
you're not aware of - there's no 'set to default' functionality. So
if some code in some plugin sets a parameter you're not expecting to
change and your code relies on that parameter, your drawing code may
be affected. That's why it's a good practice to use the
glPushAttrib() and glPopAttrib() functions to restore the current
state of whatever you're meddling with.
-jonathan
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