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RunningInt

OpenGL fast rendering of animated models

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RunningInt    133
Hi, I am looking at making a very simple 3rd person squad-based game using opengl. This will involve a static heightmapped terrain and various units which can be selected and moved across it. The units will be 3D models, but will be low quality models. I am strongly favoring quantity of units rather than quality of the models. I am going to use Milkshape3D to build and animate the models and will export them in ms3d format and then convert them into my own undecided format stripping any information out which I don't need. I am really looking at having to render these models very quickly, but this is the first time I have attempted this and am not sure what the best method would be. 1) Build the models and skeletal animations, then extract each frame of animation and store each frame as a static model. Ie this is basically converting a skeletal animated model into a series of non-skeletal animated model like the old quake2 format. This avoids calculating bone orientations at runtime, but takes up a lot of memory to store a model. I assume that if the models are low detailed enough I could fit each of the frames into a display list to render it really fast. 2) Milkshape3D does skeletal animation by attaching each vertex of the model to one joint. This means a triangle face can have each of it's 3 vertices belonging to different joints. Which means that a face can be angled dependant on the angle of two bones and not one. This makes the model look smoother at the seams, but I assume I cannot then use a display list for each bone as the vertex map for each bone is not static. 3) Build the models and animations so that each triangle face belongs to one bone. Store each bone's faces in a display list and just calculate each bone orientation in game and render its display list. This means the seams between different bones will overlap and won't be smooth. But if this method gives me a huge speed boost then I dont care. I wonder if anyone can spot any incorrect assumptions I have made here, or perhaps point out a better way of doing things. I really don't know the best method of rendering as many models as possible. My main question is over the issue of display lists. I have used them, but not very much. Would use of display lists allow me to put a lot more models on the screen at once than I would be able to do without using display lists? Or is the trade off so negliable as not to be worth it?

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nefthy    184
quake2 uses interpolation between frames to save some memory. Also it splits the model into 3 parts (head, body, feet) for the same reason. You might want to do something like this too.

Also if you have a great number of the same models it might be good to check which of them are in the same animation phase and transform calculate the interpolation only once for each group.

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