Jump to content

Quick question about venetian blinds for 96-pixel displays

Recommended Posts

I'm sure this has been asked a dozen times before, but I tried searching the forums to no avail.


If you want to create a 96-pixel display (perhaps for a 12x 8-pixel-wide character display), you might set NUSIZ to 3-copies-medium for something like this:


P0 - P1 - P0 - P1 - P0 - P1 - (the dashes represent 8-pixel-wide spaces)


Then, on the next scanline, you would shift P0 and P1 eight pixels to the right:


- P0 - P1 - P0 - P1 - P0 - P1


Then you would shift back to the left for the next scanline. Classic venetian blinds effect.


So my question is this. How do you deal with the problem of only being able to HMOVE 7 pixels to the left per scanline when you need 8 pixels? Do you need to perform a shift on the graphics to fake it? (...if you have enough cycles, otherwise you would need a second graphics table that is already shifted). That could work for a character display because there are spaces between letters. But is there a better way to do this, especially if you need to use all 96 pixels without any blank spaces? Do you need to strobe the RESPx registers in order to do this? That's the only other way I can think of that might work, but I'm not sure, I haven't done any of that yet.


I don't have any example code yet. I simply set up the players and NUSIZ, but that's it, no graphics or HMOVE's yet. I'm just trying to figure out the best way to do it now rather than going down a few dead ends.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...