Carlo
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Carlo got a reaction from jetsetdanny in Jsw Bbc Computer Version
Hi, and thanks for the JSW conversion. I've been trying to convert it for the Master myself, but couldn't get the display straight.
I had a go at your version using B-em's debugger and found out the cause for the missing items, although I still haven't come up with a simple solution.
The problem is the different text window size (14x1F on a Model B and 14x27 on a Master, according to the pokes you introduced in file JSWL).
Whenever the VDU driver clears the screen, on a VDU 12 command for example, it clears screen memory at 0x3000 to 0x59FF on a Model B, while it additionally clears 0x5A00 to 0x647F on a Master due to the larger text window. This additional area happens to contain definitions for several guardians, as well as the falling foot.
Setting the window back to 14x1F wreaks havoc on the Master display of the game. At this point I'm stuck, mainly because I'm ignorant about the video differences between the BBC Micro and the Master. For example, why does a Master require a larger text window in order to display Jet Set Willy correctly? Can you elaborate on this?
Thanks,
Carlo.
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Carlo got a reaction from Spider in Jsw Bbc Computer Version
Hi, and thanks for the JSW conversion. I've been trying to convert it for the Master myself, but couldn't get the display straight.
I had a go at your version using B-em's debugger and found out the cause for the missing items, although I still haven't come up with a simple solution.
The problem is the different text window size (14x1F on a Model B and 14x27 on a Master, according to the pokes you introduced in file JSWL).
Whenever the VDU driver clears the screen, on a VDU 12 command for example, it clears screen memory at 0x3000 to 0x59FF on a Model B, while it additionally clears 0x5A00 to 0x647F on a Master due to the larger text window. This additional area happens to contain definitions for several guardians, as well as the falling foot.
Setting the window back to 14x1F wreaks havoc on the Master display of the game. At this point I'm stuck, mainly because I'm ignorant about the video differences between the BBC Micro and the Master. For example, why does a Master require a larger text window in order to display Jet Set Willy correctly? Can you elaborate on this?
Thanks,
Carlo.