Thanks for the comments - much appreciated. Wrote a longer reply but fell into the 'logged out' trap and lost it. Bah!
Anyway the short version is: I made a new STE sample today, which illustrates collision detection. You can d/l it here:https://www.dropbox.com/s/bda6ntl2ge1ya ... n.zip?dl=0
It creates 32 squares in 4 colours and defines some rules for interactions between them:
RED <-> GREEN interact with each other
RED -> BLUE interact in one direction only
YELLOW doesn't interact at all (might change this to yellow<->yellow)
The only difference between the object types is their colour, their movement pattern (tick function) and interaction filters. Note that when lots of objects overlap, the rules are not broken. There is no limit to overlaps / depth complexity and cost is roughly flat.
This will be broken into a 2- or 3-step source tutorial (no. 6) with a walkthrough on the wiki.
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