Indivision AGA Mk3 - Pointer sprite changing its resolution when moved into the overscan area in DblPAL and DblNTSC

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Don't Panic. Please wash hands.
  • Hiya,

    Jens said to write this into a thread on it's own as I found it earlier today and had mentioned it in a different thread, so here goes in case it's worthy of investigation at some point...

    I was playing about with the overscan and resolutions on my A1200 which is fitted with an Indivision AGA Mk3 to see if either made any difference to some flickering I was experiencing (it didn't seem to), and I noticed that if I set the overscan to greater than 704 pixels in DblPAL progressive and laced, and then move the pointer sprite to the far right of the screen, the pointer sprite doubles in height. The same also seems to happen in DblNTSC prog and interlaced too. I don't have an analogue multisync monitor to check if the Amiga's normal video out does the same thing.

    Hope this is useful, cheers! :)

  • nuttie

    Changed the title of the thread from “Indivision AGA Mk3 - Pointer sprite changing its resolution when moved into the overscan area in DblPAL” to “Indivision AGA Mk3 - Pointer sprite changing its resolution when moved into the overscan area in DblPAL and DblNTSC”.
  • Hm, I'm not seeing that with my A1200 running at DblPAL 720x540 mapped to 1920x1080 by the MK3 with left = 105 and top = 2, width = 960, height = 540. This is with the 20201014 firmware.

    I tried to connect my A1200 to a VGA display but then it wouldn't boot properly? Weird.

  • Weird, maybe it's another bug/defect in my particular Lisa chip (along with the glitching I see whenever I first power the Amiga on from cold when in DblPAL). yay. *sob*... ;)

    My Workbench preference settings are (in case it's a particular sub-setting that causes it)...


    High res


    DblPAL: High Res No Flicker, 64 colours.

    Current Position : (0 ,20)

    Current Szie: 704 x 512

    When I open up the overscan preferences tool with these settings active, and move the mouse pointer to the far right of the screen, past the right border and the drag handles, the mouse pointer doubles in height. If I then set the overscan preference to wider than 704 pixels, the same thing then happens on the Workbench screen too.

    At present I have my Indi Mk3 running in 1920x1080@50Hz, I tried changing this to different modes, 1920x1080@60, 1280x1024@60, 1024x768@60, 1280x720@50, 1280x720@60 but it did not seem to affect the behaviour in any way.

    If anyone else feels like trying to see if this behaviour also happens for them, that would be great. I guess at least then I'd know if it's something to do just with my A1200.

    Cheers! :)

  • What OS version are you using? And what settings in the MK3 tool?

    This is what I have on a PAL A1200 running AmigaOS 3.1.4:

    DblPAL 32 (or 64) colors, 720x540 screenmode

    Overscan graphics position 0,0; size 720x540

    Overscan text position 0,0; size 720x540

    IndivisionAGAmk3 1.7 (using 20201014 firmware) "VGA" mode:

    Pixel clock: 123.75 MHz

    Horizontal: 1920, 88, 44, 148, Pos

    Vertical: 1080, 5, 5, 35, Pos

    Select: always

    Lines: min 567, max 605, current 591


    Left: 105

    Top: 2

    Width: 960

    Height: 540

    Res.: SHires

    I usually use borderblank but for this that's not necessary as the borders on both sides are already black.

    This works just fine with no distortions at all and the mouse pointer can go to all edges of the screen.

    (I was actually having some trouble making a good NTSC mode earlier where I did get strange stuff on the right edge of the screen, and I've also seen the mouse pointer disappear when it gets close to the right side of the screen in at least one mode, so I do have some experience with weirdness in some situations.)

  • Hiya,

    Firstly, thanks for helping!

    I tried to mirror your settings to see if they changed any of the behavior but I still see the same effect on the mouse pointer. Your monitor timings are not compatible with my monitor/hdtvs, I have to run my 1080p mode at 148.5MHz and with a horizontal front porch of 528 for 50Hz but other than that they're identical - I don't think the 1080p timing differences are causing what I'm seeing as I've tried lots of different output modes and none t seem to change the behaviour at all.

    How are you setting borderblank? it's not an option I can see anywhere in any of the preferences, so I assume it's a tool that modifies the copper list of the screen? I don't have anything like that installed or active on my operating system.

  • How are you setting borderblank?

    It's a tool from Aminet.

    Once again, I believe what you're seeing is not happening due to Indivision MK3. I am very sure that Indivision AGA MK3 merely makes it visible. Did you ever post the exact type of Lisa that you're using? We should have at least one A1200 here with "your" kind of Lisa to reproduce the problem.

  • Oh wait, there is one thing that makes a difference: I use VGAOnly in DEVS:Monitors, as the VGA monitor I used to use needs it.

    Without VGAOnly the overscan is very different and my mouse pointer doubles in height when I get to the right side 16 pixels of the screen. Mystery solved, I guess: use VGAOnly. 8)

    SYS:Tools/ShowConfig tells me I have an AA Lisa (id=$00F8).

    I got BorderBlank so long ago that I actually forgot it's not part of the system... But recently I started using Copper-Demon which canalso turn on the borderblank feature with the right tooltype.

    Copper-Demon's main purpose is showing a nice background color gradient using a custom copper list, but it has an important extra feature: you can set the size of the mouse pointer. This is useful in some screen modes that make the mouse pointer look weird. Doesn't overrule the height issue, though.

    As I'm going on and on anyway: FreeWheel lets you set the mouse speed in the X and Y directions independently, which I find useful on SHires-based screenmodes, as well as improve the functionality of the scroll wheel (useful with a USB mouse with RapidRoad).

    (Good thing I upgraded to 64 MB fast RAM so my A1200 can hold all these tools in memory.)

  • Yep, that's definitely the cause - good find!

    I didn't have VGA only enabled as I don't have a VGA monitor, so I didn't think it was needed. As with your Amiga, mine displays the pointer sprite fine with VGA only copied into the Devs:monitors/ directory, but without it, the sprite doubles in height within the right hand 16 pixels of the screen. I wonder what's causing it?

    On my Amiga, there's also quite a shift in the screen's relative position within the overscan area, and an increase in the number of lines output with VGA only enabled too. I guess this is just a shift in the porch and sync etc.?

  • Hm, maybe that's part of it but it also looks like the horizontal and vertical timing is fairly different with and without VGAOnly.

    Would you be interested in discussing setting up custom screenmodes in a separate thread?

    One I've been working on is a modification of Euro36 for 540 visible lines (i.e., 1080p / 2) at 25 Hz with no interlace, and then see how much additional horizontal overscan is possible. That would be a good mode for web browsing, where you need a lot of space but really can't afford a 70 ns pixel mode with 256 colors, that's way too slow. However, I just can't figure out the settings to change to get the extra overscan.