pygame / Document / Physics algorithm.txt

minz 7a9702e 

1.Simulation Step Algorithm
	Collision Detection and find all contacts
	Find and build awake islands (An island contains bodys and joints which are connected together)
		Depth first search algorithm to the body joints connect graph
		when no body in the island is awake, the island is sleep 
	Simulate awake islands
		Free bodys simulation: Integrate velocities and apply damping.
		Solve contacts and joints interatively
		Update bodys positions
		update body's states: whether it's sleep now. 
	Post step
		clear contact list
		clear islands