Monday, 7 December 2015

There was movement at the station...

I've made some pretty decent progress today at lunchtime and this evening, deducing the purpose of no less than three more bytes in the object table, identifying another two as flags (leaving just 6!) - and the purpose of 3 of those bits - and a handful of global variables.

I thought I'd choose an object with the simplest movement - the portcullis that moves only up and down (i.e. along the Z axis) - and try to reverse engineer the handler for that object. It was quite successful, so much so that I now have a fully animated portcullis! Not unexpectedly this involved some generic low-level movement routines which are used by all the moving objects, such as bounds checking on the object which, of course, are also now implemented in C.

I guess I'll stick with the objects with the simplest movement logic, and work my way through to more complex object behaviour. Somewhere along the line the rest of the object table bytes should fall into place. Note that there is quite a lot of code to get through, and the next update of any significance may be a while away yet.

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