Re: Mental challenge: the rainbow

["Marc S. Ressl" <mressl@gmail.com>]

On Feb 10, 3:01 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> BLuRry wrote:
> > Is it possible to sync with VBL such that during VBL, and during the majority of each HBL the apple is put in a text mode but during active signal output throw it back to graphics?  That should fake out the apple to not send a color bust, right?   Would be interesting to get a grayscale mode... really just for kicks if nothing else.
>
> As Vlad recently noted, NTSC monitors do not switch instantly from color
> to monochrome and back.
>
> To allow for color reception under marginal signal conditions, the mode
> switching typically occurs over several frame times, and is a precise
> standard, so this switching 1) cannot be done quickly, and 2) cannot
> be done with reliable results for various monitors.
>
> Typically, switching from monochrome to color occurs more quickly than
> switching back from color to monochrome, but both time constants are
> long relative to intra-frame times.
>
> -michael
>
> NadaNet 3.1 for Apple II parallel computing!
> Home page:  http://home.comcast.net/~mjmahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."

Hello everyone:

this opens yet another issue I wasn't aware of... in my emulation I do
consider the color carrier, and you can even specify color carrier
phases for every line :-).

But the choice of color or monochrome is based upon sampling the color
carrier at the beginning of the frame. Do you consider that
appropriate?

For example, in the split screen code of the "Test: the cycle" thread,
color is shown depending on whether there was color carrier at the
beginning of the frame or not...

With the best wishes,

Marc.-