3D modeling / animation / rendering

Newbie & Debugging Questions
#1

I didn’t know whether to post this on jogl or this newb area.

I’m using jogl / openGL to render 3D objects. I’m to the point of wanting to render objects
which have movable parts animated in a game. For example, a human arm that can bend.

In OpenGL I’m using drawlists. And I understand with movable parts, I’ll likely need
to split the object into vertex groups connected to virtual bones which control orientation
of the groups of polygon mesh.

However, if I try to assign a drawlist to each group, the different polygon mesh groups do not
connect. The connecting faces between groups do not completely exist in either matrix arrangement
for either group.

So for example, if I have one drawlist which is a hand, and one which is an arm, and thus
a different matrix for each drawlist. How do I draw the connecting faces which contain points
from both groups?

I can think of a couple different ways… calculating the points outside drawlists… having
overlapping polygons, but neither of these seem very good ideas.

Thanks for any references.

DarkDerivative

#2

Look into using skeletal animation. You have a bone weight associated with each vertex and then the final vertex position is calculated based off of the bone transform. This can be accomplished in a shader. I know this scheme works with vertex buffer objects and I’m fairly certain that it would also work with display lists (you’d just need to specify weights in the display list as well as other more standard mesh information). Then each time you want to render the mesh, just set the bone transform variables in the shader to the ones for the current mesh, and then call the display list.

#3

Thank you.

This game programming hobby is never boring.

This should keep me off the virtual streets for a while…

DarkDerivative