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Message: 6899

Author: ian.rushforth

Date: 05/08/2016

Subject: Re: Mirror MM/JSW / MM - JSW Conversions

 

Daniel said:

In "ylliW teS teJ" I noticed that there are some things which are
not inverted, such as ropes or arrows (or so it seems, at least).
This creates some differences with the original in the gameplay. I
had a nasty surprise when I discovered that you cannot climb down
from "rewoT hctaW" ("Watch Tower"), because the rope in the room
below keeps throwing you upwards, back into "rewoT hctaW". So I
couldn't take what I consider to be the most effective route
around JSW (climbing down from "Watch Tower" after collecting the
items and later exiting upwards in "Rescue Esmerelda"), and I had
to use the second most efficient route, which involved re-
recording most of the game!

Andrew said:

Ropes start at a different place in the swing when going right

initially as opposed to left. I should look into this further one day.

I was thinking about that. In order to create a Rope with true symmetry, I believe you need to:

(a) set Bits 7 of Byte 0 and Byte 1 of the Rope's Definition Bytes (so in original JSW, instead of having values of #03 and #22 at #A008-A009, you would have #83 and #A2 respectively); and

(b) change the value of #92B5 in the rope-drawing code from #80 to #01 (i.e. the right-most bit set for the 0th segment of the Rope, rather than the left-most bit).

The latter value is hard-wired into the game engine. I tried inserting the appropriate value into Byte 5 of the Rope Definition at #A00D - which would open up the possibility of different Rope Classes for which the top segment occupies a different position within its cell-column - but it made the top of the Rope 'jiggle' from side-to-side (I think because the 'copy' of Byte 5 of the Rope's Definition in the Buffer at #81X5 or #81XD is subject to constant updating as the Rope is drawn/animated).

 

 

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