Jump to content
  • 0
Geehaf

HSCALE and visual artefact

Question

Hi All,

Out of curiosity, does anybody know what the coloured lines are that appear at the end of a line when I set the HSCALE ($9F2A) register to 255 - see below.

Interestingly when I move the cursor around the screen area they change colour - try it out yourself by typing POKE $9F2A,255 (I'm using R38).

My thought is these lines represent some form of register artefact, but I am just guessing.

Cheers,

G
 

image.png.25eb0b5f2b945e470b3f17eb96fa94d9.png

Share this post


Link to post
Share on other sites

2 answers to this question

Recommended Posts

  • 0

My guess is that this is probably an emulator bug. The real X16 would wrap the display once it reaches the edge of the tilemap, so you should see at least part of the X16 logo and whatnot towards the right edge of the display (it being a 128-wide layer, and a scale of 255 showing around 159 tiles).

I would guess that one of the VERA speed optimizations broke this, and I worry we could be looking at some of the emulator's internal memory...

  • Like 1

Share this post


Link to post
Share on other sites
  • 0
11 hours ago, StephenHorn said:

My guess is that this is probably an emulator bug. The real X16 would wrap the display once it reaches the edge of the tilemap, so you should see at least part of the X16 logo and whatnot towards the right edge of the display (it being a 128-wide layer, and a scale of 255 showing around 159 tiles).

I would guess that one of the VERA speed optimizations broke this, and I worry we could be looking at some of the emulator's internal memory...

Thanks Stephen - I suspect it's in that space too.

For my current project, my idea for a workaround is to use the Horizontal Stop register (DC=1, $9F2A) to mask it out - example below.

Cheers,

G

image.png.b344b5e2bac132fb45cab920a72cb26e.png

Share this post


Link to post
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.

Guest
Answer this question...

×   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.


×
×
  • Create New...

Important Information

Please review our Terms of Use