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lack the hack

OpenGL animation

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hello everyone:-) i was wondering exactly how do you do animation in openGL? i know how to animate md2 models and all, but i was wondering, how do you animate a stick figure that was drawn by vertexes? do you do that with physics and stuff, or is there an easier, shorter way?

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OpenGL doesnt handle animation, you just give it the details of what to draw and it draws it.

To animate things you have to change their vertex positions in some way, either by hand or via a vertex shader (which is the closest OpenGL comes to handling animation for you, but even then you have to specifiy how far to more/interpolate and where from/to).

If you wanted a more general answer about animation then post and I'll move it to a better forum [smile]

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ok, thanks for the info phanton:-)
yeah, then can you move this to a differnet forum? ok, thanks a bunch.

but back to my orginal question, how should i handle animation? (without using models)

[Edited by - lack the hack on July 19, 2005 8:34:55 PM]

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sorry for the double post, but can anyone help me out? I really need help with it, since this is the most important part of making games. (i'm also making a game right now, even though i'm probably not ready for making one.

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The "Stick Figure Animation" you described is commonly called "Skeletal Animation". It's often associated with a technique known as "skinning", which is simply modifying a vertex mesh based on the underlying skeleton. All togehter this is a very broad topic, and one that is probably beyond the scope of a single forum post. I would reccomend checking out this Wikipedia Entry for a much more in-depth analisys of the technique, and afterwards I would suggest researching a pre-existing skeletal animation format and trying to write a simple viewer for it. The Doom3 MD5 format is nice, since all files are in plain text form, but you can also take a look at the original half life models, or even just your basic milkshape models.

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thanks for the reply:)
since you were mentioning models, i have a questions about .md2 models. MD2 models are pretty much just a mesh of triangles, right? well, i used this program and tried making an MD2 model out of triangle meshes, but when i tried loading the MD2, it just didn't show up. i saved it as a .md2 file too. so how exactly is the best way to go about making your own custom made MD2 models?

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You're using too many pronouns ... or something. What program did you use to make the .md2, did you use an exporter to put your mesh in .md2 format? Judging by your description you may have just saved the file as .md2.

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i used a program called AC3D. i selected the mesh option, and made my model out of meshes of triangles. then i saved my file as fighter.md2. yet, when i try to load and display my model, it doesn't work. what would your recommendations be?

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Quote:
Original post by lack the hack
i used a program called AC3D. i selected the mesh option, and made my model out of meshes of triangles. then i saved my file as fighter.md2. yet, when i try to load and display my model, it doesn't work. what would your recommendations be?

lol did you actually use the MD2 exporter or did you just save the filename with the extention .md2?

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