C64 Graphics Mode for BT1

Discussions and help for Bard's Tale I: Tales of the Unknown
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Sultaneous
Posts: 2
Joined: Tue Jul 21, 2020 3:40 am
Location: Ottawa, Ontario

C64 Graphics Mode for BT1

Post by Sultaneous »

What graphics mode does BT1 use on the C64?

I suspect it is using 160x200 multicolor bitmap mode, with bitmapped fonts. But it could also use text mode split for the lower portion. Can someone who has worked with the disassembly confirm the graphics mode used? Thanks.
Sultaneous
Posts: 2
Joined: Tue Jul 21, 2020 3:40 am
Location: Ottawa, Ontario

Re: C64 Graphics Mode for BT1

Post by Sultaneous »

Using this python utility and Vice 64, I can confirm it is Multicolor Bitmap Mode (160x200). I can't confirm if it is doing a text split for the bottom pane; I've overwritten screen memory in that location with no impact, so it doesn't seem likely. But I'll have to test more, perhaps trap the raster interrupt and check.

-->
python c64gmode.py

Syntax: c64gmode.py <$D011> <$D016>

Where the params are the 8 bit values of those memory
addresses (grab them from Vice monitor with 'm $d011 $d016')
-->
python c64gmode.py 0x3b 0xd8
Bits --> 00111011 11011000
Mode --> (3) Multicolor Bitmap Mode (160x200)
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Darendor
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Joined: Wed Jan 14, 2009 1:53 am
Location: Red Deer, Alberta, Canada

Re: C64 Graphics Mode for BT1

Post by Darendor »

This probably doesn't help much, but the animated icons for the exploring spells (light, carpet, eye, shield, compass) are sprites. Obviously animated, with the exception of the shield which is static, and the compass which displays which direction you are facing (spinners notwithstanding).

Which makes me wonder, if an archmage casts BASP, how do they display more than 16 sprites at a time? :?
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