Sunday 11 May 2014

Experimenting with Skeletal Animation ideas.

Graphics by Ray Wenderlich
I've been experimenting with some Skeletal Animation bits and bobs. The demo shows my first go, on the right (the Elf image is from Ray Wenderlich's Spine Tutorial)

Actually it's the second go but I can't draw for toffee, you wouldn't have wanted to see the original graphics....

I wanted something Spine-esque but simpler, however great Spine is the Corona library doesn't work (v1 Graphics) and it's still £100.

This makes some simplifications for simplicity and speed. All the graphics have to be aligned vertically top-up and their anchor points are on a vertical line through that graphic, though they can be moved up and down that line - see where the anchor point is on the bottom part of the body, it's 20% inwards.

This vertical line can be moved though - if you look at the legs the vertical line is way over to the left

If you look below (perhaps) you can see the arm - having it automatically in this vertical position saves a lot of math, but it does add limitations

The arm - notice
the vertical orientation
Any of those images can be placed between any two points on the skeleton (highlighted for debugging purposes as a yellow line) and then those points can be moved arbitrarily.

The big advantage of the simplification in the graphics bit is that there is no complex munging of the image or the line to make it work, it is about 3 or 4 Corona API calls and a little bit of simple mathematics.

I plan to experiment a bit further and then once that's done see if people have any useful suggestions or ideas.

The development version is currently at https://github.com/autismuk/coccyx and should normally be in a working state though of course it is in regular development.

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