5 replies to this topic

[Pixelboy]

I could test this myself, but I'm thinking I can get clearer information by simply asking here.  

I would like to know what happens exactly when screen_off() is used. Does the screen turn black until screen_on() is called? Or is the current graphic display just frozen on the TV screen?

[hardhat]

The screen_off() stops displaying everything except for the background colour.  So that way when you are massively updating the graphics tables you don't see flashes of garbage displayed while the screen is updated.

[Pixelboy]

hardhat, on Fri Apr 27, 2012 9:51 PM, said:

The screen_off() stops displaying everything except for the background colour.  So that way when you are massively updating the graphics tables you don't see flashes of garbage displayed while the screen is updated.

Yeah, I know. But what I wanted to know is what I would see on the screen if I made intensive graphical rendering that would require a couple of NMI cycles before calling screen_on() to display the results.

You've pretty much answered my question, so thanks.  

[hardhat]

Just the background colour and nothing else.

[Pixelboy]

By the way, does the VDP stop sending a NMI to the CPU every 60th of a second while it is disabled this way?

[hardhat]

They are independent flags so I would expect the NMIs to continue as usual, but I haven't specifically done that in a while.