obsolete feature used in old atari games

[erichenneke]

Also,  on the A8 computers, if a game only uses joystick or paddle input and no keyboard keys are pressed,  then the attract mode will kick in during game play.  The user can get out of attract mode by pressing a key on the keyboard. 

 

To avoid this, the software program must disable the attract mode on a regular basis during the gameplay.

 

 

[zzip]

17 hours ago, leech said:

So is it a function built into the OS, and hence something that needs to be disabled in software, or is it something that just happens to be included in BASIC as well (and hence it wouldn't work on say the 400/800's memopad?)  Always sort of wondered about that.  I don't think I ever saw it on the 2600 as we wouldn't let that thing alone fir more than 7 minutes.  ?

I believe it's called "Attract Mode" -- the named it after the mode an arcade machine goes into when idle.    It's based on a timer.  I seem to recall that it could be disabled from BASIC with a single POKE,  or you could force it into that mode too.   But it isn't BASIC only, it would affect all apps unless they disabled it.

[+Stephen]

2 hours ago, zzip said:

I believe it's called "Attract Mode" -- the named it after the mode an arcade machine goes into when idle.    It's based on a timer.  I seem to recall that it could be disabled from BASIC with a single POKE,  or you could force it into that mode too.   But it isn't BASIC only, it would affect all apps unless they disabled it.

Memory location $4D (77 decimal) tells the OS whether or not to use attract mode.  0 is normal, 128 will turn it on.  There is code in the OS (not BASIC) that runs the timer to set this value.  If you are writing a game, or demo, to disable attract mode, you must periodically store a 0 to that memory location.

 

POKE 77,128 in BASIC will immediately turn it on though.

 

10 ? PEEK(77):GOTO 10

 

Running the above code, you will see the value slowly increasing as long as you don't press a key.  When it gets to 128 (meaning bit 7 goes high) attract mode comes on.  Pressing any key will reset the value to 0.

[zzip]

37 minutes ago, Stephen said:

Memory location $4D (77 decimal) tells the OS whether or not to use attract mode.  0 is normal, 128 will turn it on.  There is code in the OS (not BASIC) that runs the timer to set this value.  If you are writing a game, or demo, to disable attract mode, you must periodically store a 0 to that memory location.

 

POKE 77,128 in BASIC will immediately turn it on though.

 

10 ? PEEK(77):GOTO 10

 

Running the above code, you will see the value slowly increasing as long as you don't press a key.  When it gets to 128 (meaning bit 7 goes high) attract mode comes on.  Pressing any key will reset the value to 0.

Interesting-  I thought there was a way to turn it off completely.   I suppose since most BASIC programs are interactive, they aren't really in danger of going into attract mode, so you didn't have to worry about it most of the time.

 

What happens when the counter hits 255?  does it roll over to 0 or stick there?

[+Stephen]

1 hour ago, zzip said:

Interesting-  I thought there was a way to turn it off completely.   I suppose since most BASIC programs are interactive, they aren't really in danger of going into attract mode, so you didn't have to worry about it most of the time.

 

What happens when the counter hits 255?  does it roll over to 0 or stick there?

It will count up until it hits 128, Attract Mode turns on, then the value remains at 254 until a key is pressed.

[Keatah]

We loved these changing colors on the screen. At 1am in the morning. Moody. Dark. A different realm. The hiss of the CRT. The background noise on the speaker. A great way to let us know it was late and time for scary stories.

[+SpiceWare]

On 4/27/2021 at 12:49 AM, glurk said:

That is called "attract mode" and it's built into the 2600 itself.

 

No, it's not built into the 2600.  I show how to implement the attract mode in step 8 - Select and Reset support of my tutorial. It cycles color or shades of grey depending upon the state of the TV Type switch.

 

 

 

[leech]

3 hours ago, SpiceWare said:

 

No, it's not built into the 2600.  I show how to implement the attract mode in step 8 - Select and Reset support of my tutorial. It cycles color or shades of grey depending upon the state of the TV Type switch.

 

 

 

Yeah, I think Attract Mode came to mean the cycling of screens for arcade games, which serves sort of the same function to help prevent screen burn in. 

Screen burn in is funky.  Funny thing is that I remember it was touted as one of the advantages of CRT, that burn in couldn't happen... nope I have seen it.  It is also the claim of why we no longer have screensavers as a thing... yet now most computers / systems will just go into sleep mode if they are unused.  Either way, it looks sort of cool to cycle the colors.

[zzip]

On 7/30/2021 at 7:57 PM, leech said:

Yeah, I think Attract Mode came to mean the cycling of screens for arcade games, which serves sort of the same function to help prevent screen burn in. 

Yeah it's one of those names that stuck, even when it stopped making sense.   Besides burn-in the point of "Attract Mode" in an arcade machine is to attract players.   But on VCS/8-bit computers, the so-called attract mode is not very attractive.

[Video]

Haven't thought about it in years. Many vcs games go to color cycling immediately on final death (I think all the 77 games do) but as time went on and games got proper attract modes this largely disappeared.

 

Always thought it would be cool to "lock" the color cycle so you could play the game in different colors.