I have indeed accomplished this goal. I made a simple animation in Maya (only 16 frames long) and copied over the keyed position and orientation values by hand into a "keyframe" file (or KF). The KF file is a format that I devised using the OBJ format as inspiration. As far as I know, there are a couple other data formats that also have the .kf extension, but none of them seem to be extremely popular (I could always change the extension name to something else - it's just a renamed .txt file; that's all). Here is the test.kf that I created based on the Maya animation. To enter my project pipeline, a person would have to construct a converter to take their animation format and convert it into the KF format. This would not be very difficult, considering the simplicity of the KF. Hopefully the fact that it uses Euler angles won't be a problem.
(click to enlarge)
Goal: Parse the .kf file and store its data in a dictionary whose keys are frame numbers and values are position/orientation vectors
Well, I didn't end up using a dictionary data structure. Vectors with index values corresponding to keyframe numbers work just fine (negative keyframes are also possible in theory; my parser uses the start and end frames of the KF to calculate the offset needed to extrapolate vertex index numbers from keyframe numbers and vice versa).
Goal: Develop a simple GUI that allows the user to change the position/orientation of a rendered master control node according to the parsed .kf data (i.e. "play" a .kf animation)
I also accomplished this one. Check out the videos below to see the comparison between the test animation being played in Maya and test.kf being played using my GUI. To play back animations at the correct framerate (barring some other big process slowing my computer down, which might happen when the sim is brought over), I used a timer class that measures system ticks. I did not write this class (I found it here), but it uses common functions provided by both Windows and Linux OSes (I'm trying to keep things as platform independent as I can; as far as I know, FLTK/GLUT is platform independent; the only thing that isn't is my VS project file).
(first with Maya - I had to loop the animation manually, since letting Maya do the looping made the animation a little crazy)
(and here's my version - the messing around in the beginning is to show off the scene camera)
Since the new GUI is hard to see clearly in the video, here's a larger screenshot:
(click to enlarge)I have not yet accomplished this one. But I will keep working towards it! Here's how I plan on breaking it down:
- Insert all the necessary dependencies and linker definitions for Bullet into my VS project
- Create a class that asks Bullet for the vertices or faces of the head rigid body shape at each frame and uses this information to draw the shape (perhaps store the geometry data in an OpenMesh data structure) - I'll need to sift through the Bullet demo application code to find where/how scene objects are being drawn (maybe all I need to do is copy over a couple functions)
- Create a class that takes a pointer to the control node as input and generates force/torque values (using feedback controls), which it then applies to the Bullet head - if force and torque can't generate "instantaneous" control over the rigid body head, then I'll need to figure out how to generate velocity values instead
- Finish the remaining goal specified above
- Add the ability to render/draw the original input head and scalp OBJs (perhaps store the geometry data in an OpenMesh data structure)
- Add the ability to render the Bullet soft body key hairs as lines
- Read papers (and dissect tutorials) pertaining to writing shaders - I can't seem to make up my mind when it comes to which method of rendering I want to implement; hopefully more research will help me choose
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