Re: [stella] My demo...

Subject: Re: [stella] My demo...
From: "Thomas Jentzsch" <tjentzsch@xxxxxx>
Date: Mon, 28 May 2001 15:50:47 +0200
Eckhard Stolberg wrote:
> > INPT4 is correct, but you should check only for bit 7 (just change bne to
> bmi). The other bits are used for something different (which i can't
> rembember now), and are not always zero.
> Actually these bits aren't used for anything. 

Oh, that's why I couldn't remember... ;)

> The programming manual lists
> them as 'undefined'. I think on the 2600 they just keep the data that was
> on the bus last. The Stella emulator always sets these bits to '1', PCAE
> always sets them to '0', and z26 sets them to the lower bits of the address
> of the register that currently gets accessed, as this most of the time
> seems to be what was on the bus last. 

Now, that explains the different behaviour of Gonzalos demo.

> As for the colours, the one you chose for the water is torquise, which
> is somewhere in the middle between green and blue. Chosing the 'real'
> colours for the emulator is quite difficult, since the colours can be
> tuned in the VCS, on the TV, and on the PC monitor. So what you see
> on your TV and on your monitor is pretty much different for everyone else.
> I think Brad just chose the colours to be what they should be ideally
> by the desription in the programmers manual. Both Johns seem to have
> tried to match the colours on their TVs with the colours on their
> monitors running their emulators. Which of the three emulators fits
> the colours on your TV best is something that you have to find out
> on your own.

Some emulator colours differ so much, I can't believe, that there is no way to find the (nearly) correct colours. 

You can eliminate the monitor by getting the colours from a TV-card (like you just did with the updated colours for the Secam-palette in z26). 

For the different VCS colors we could try to do get as many samples as possible from different VCS. Just find some common games (like PacMan, Space Invaders, Pitfall!, ...) which nearly everybody owns and capture some screens which show many well known colours. 

Then it would be quite easy to define an "average" RGB-triple for each coloor.

Or is it a general problem with NTSC (Never The Same Colour :) ? What about the PAL palettes then?

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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