Scroll info MSX2 + / Turbo R

By OrazioLC

Supporter (12)

OrazioLC's picture

22-09-2022, 12:22

Hello everyone.
I'm just starting out with the basic MSX2 + and Turbo R. I'm making a side scrolling mini game. I would like to know which register to manipulate to block the first upper lines of the screen. I would like to enter the score and not slide it with the rest of the background????.
Thank you

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By Sandy Brand

Champion (285)

Sandy Brand's picture

22-09-2022, 14:32

From your post it seems like you want to build something in MSX BASIC? Unfortunately, the VDP does not support something like that with just some simple register settings, and you will need to build something using assembly code.

You will need to setup a screen-split where the top of the screen will be rendered with a fixed horizontal/vertical offset, and then in the interrupt handler you modify some VDP registers to set the variable horizontal and vertical offset of the bottom part of the screen.

For more information, see here.

If you still want to stick to MSX basic, you could look into some of the character-based screen modes (Screen 4?), but you will not get easily get smooth scrolling effects there.

By OrazioLC

Supporter (12)

OrazioLC's picture

22-09-2022, 15:08

A thousand thanks. I had a half idea that with the basic it could not be done, you gave me the confirmation.