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Post by oziphantom on Feb 26, 2019 14:36:59 GMT
So the VDC has a bitmap mode (Graphics mode) and that is lovely, however it has catch.. 640x400 = 16K and then you need attributes which needs 2K and you only have 16K.. rats..
However 40cols is 8K and then 1K for attributes.. fits with plenty to spare for dma buffers and other data..
Only it doesn't seem to work..
On the real 128 I get vertical lines and a screen doesn't look happy solid vertical 8 pixel wide bars of white then black, with the left and right borders being white ( I have set attributes to be black,white) and it flickers with corruption randomly.
On a emulator both Z64 and VICE its works almost as expected, only it shows 40chars, but still internally move memory as if it is 80 chars wide.
my regs are as follows
0 63 1 40 2 55 3 69 22 $89
25 215 27 40 34 63 35 52 20 $20 21 $00 12 00 13 00
Anybody know of or tried 40 col bitmap before? Some extra special setting that needs to be tweaked?
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Post by oziphantom on Feb 26, 2019 14:52:08 GMT
ignore the bit about it not working on hardware, I was just being stupid and forgot that when I boot with an EF it goes straight to c64 mode and hence the VDC is not initialized. However Hardware does now agree with the "it always moves over 80 columns" However I might be able to hide the attributes into the "off screen part of each row." unless somebody knows how to make it work as per normal  |
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Post by remark on Feb 26, 2019 21:39:07 GMT
So the VDC has a bitmap mode (Graphics mode) and that is lovely, however it has catch.. 640x400 = 16K and then you need attributes which needs 2K and you only have 16K.. rats..
However 40cols is 8K and then 1K for attributes.. fits with plenty to spare for dma buffers and other data..
Only it doesn't seem to work..
On the real 128 I get vertical lines and a screen doesn't look happy solid vertical 8 pixel wide bars of white then black, with the left and right borders being white ( I have set attributes to be black,white) and it flickers with corruption randomly.
On a emulator both Z64 and VICE its works almost as expected, only it shows 40chars, but still internally move memory as if it is 80 chars wide.
my regs are as follows
0 63 1 40 2 55 3 69 22 $89
25 215 27 40 34 63 35 52 20 $20 21 $00 12 00 13 00
Anybody know of or tried 40 col bitmap before? Some extra special setting that needs to be tweaked?
I have a working ZX Spectrum mode (32x24 chars, bitmapped) with these settings (PAL-B, flat C128): 0 63
1 32 2 55 6 24 22 137 ($89) 25 208 ($d0) 12 0 (display start)
13 0 20 24 (attribute start)
21 0
The rest of the registers is unchanged from default.
In your case reg 1 would become 40, reg6 25 and different attribute start.
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Post by oziphantom on Feb 27, 2019 7:23:09 GMT
reg 27 is + reg 1 not a set value.. so it needs to be 0 not 40 sigh..
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Post by oziphantom on Mar 2, 2019 10:44:09 GMT
For people to look at, as its not been shown anywhere as far as I know. Here is a 40 col bitmap scroller running as fast as it can, which is DAMN fast. Its in 480p so I can record at 50fps, so you can see just how fast it can be. 128VDC_480p50.mp4 (3.07 MB)
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Post by remark on Mar 4, 2019 13:50:12 GMT
That looks great! Is all the data pre-loaded in VDC-ram?
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Post by oziphantom on Mar 6, 2019 6:13:35 GMT
No the tile column is plotted along the side as needed. I dropped the bitmap to 40x22 so I can double buffer it.
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Post by Pyrofer on Mar 28, 2019 11:15:09 GMT
Looks like you are doing exactly the same stuff I was doing recently!
I had a vertical scrolling thing and was working on something like Spy Hunter, but I got bogged down in virtual sprites for the cars. I couldn't get horizontal scrolling to work smoothly! can you share you code for doing that? I had horrible jitter no matter what I did.
If I could go back in time and meet the guy that told Bil Herd that the VDC was a superset.... Damn that missing multi colour character mode!
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Post by oziphantom on Apr 2, 2019 11:50:29 GMT
I'm getting horrible jitter on it at the moment, as the Attributes shift a frame behind I think. Is this the it latches stuff before VBLank, and hence the attributes are off for the entire frame and not just the first row?
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Post by oziphantom on Apr 2, 2019 11:55:48 GMT
@pyrofer this is bitmap scroll, is that what you want, I don't do fine scroll so it shifts an entire 16 pixels per shift. Or do you want char mode scroll?
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