Auto Racing Original Steering

[intvnut]

On 5/29/2020 at 4:36 PM, BSRSteve said:

When you say "original steering", which mode are you meaning. I believe that the "development history" currently on the BlueSkyRangers site, which was written by Keith and brought straight across from the intellivsionlives site does not have it correct, but I have not gone back to fix it yet.

When I analyzed the ROM images, I came to the same conclusion.

 

Lots of posts starting about here:

 

 

 

Lots of low level tidbits here: 

 

 

Evidence that the Real Steering Only version is newer:

• Splash sound effect when hitting water.
• More sophisticated handling for driving out of water.
• Two grass "depths" that actually work.  (Support is in both versions, but it works more effectively in the Real Steering Only version.)
• More responsive/sophisticated controller input handling.  The "real steering" hidden in the Intuitive/Directional dual-mode version was more primitive.
• Game ending re-enables the EXEC event loop (and therefore allows the screen to blank when idle).
• Dead code in the Real Steering Only version left over from the Intuitive/Directional version.
• Generally more optimized, clever code sequences.

 

At least the part about a row with no trees has been confirmed.  (The checkerboard bits are "tall grass", exposed by a ROM patch.)

Edited June 15, 2020 by intvnut
cleanups/consistency

[+fdr4prez]

20 hours ago, intvnut said:

At least the part about a row with no trees has been confirmed.  (The checkerboard bits are "tall grass", exposed by a ROM patch.)

I recall doing this as a kid in the '80s

 

i don't remember the tall grass, but it has been a very long time.

 

Maybe there is more than one endless path?

[intvnut]

2 minutes ago, fdr4prez said:

I recall doing this as a kid in the '80s

 

i don't remember the tall grass, but it has been a very long time.

 

Maybe there is more than one endless path?

If you had the "intuitive / screen-directional" steering version, the tall grass slows your vehicle down by a lot less than the "realistic steering" version does.

 

Also, in the regular game, that grass looks the same as any other grass.  I just have it shaded to make it obvious where it exists.

[mr_me]

On 6/15/2020 at 4:58 AM, intvnut said:

•  
• Game ending re-enables the EXEC event loop (and therefore allows the screen to blank when idle).

Does this mean Auto Racing doesn't use the exec event loop during gameplay.  I sometimes call it the exec game engine, maybe not an appropriate term. 

 

Do you happen to know what frame rate Auto Racing runs at.  I read exec games drop to 15fps when scrolling is involved.

[intvnut]

5 hours ago, mr_me said:

Does this mean Auto Racing doesn't use the exec event loop during gameplay.

My statement only applies to the game ending.  The original game ending falls into an infinite loop, as opposed to following the usual EXEC convention of returning to the EXEC.  If I'm not mistaken, the net result is that the EXEC won't blank the display after a sufficient idle period in the first version.  Someone will have to check for me, since I don't have the time to play a game right now.

 

The EXEC is structured primarily as a series of callbacks into your game.  You set up timer processes, object dispatches, etc. that get called by the EXEC as appropriate.  Auto Racing is no exception.  It does most of its work on one or two timer driven tasks.  (2 for intuitive/directional, 1 for realistic-only.  The latter merged the two.)

 

The EXEC's default model expects most game code—basically anything outside a replacement interrupt handler—to run in a "dispatch context."  EXEC calls that block effectively implement a yield by "returning to your caller's caller," making it even funkier.  For example, if you call the EXEC for numeric input from a keypad, you're really yielding, and falling back into the EXEC idle loop. 

 

For example: Decimal input blocks until the user inputs a number.  When you call it, it sets up a special controller dispatch to collect digits, and "returns to caller's caller" to fall into the EXEC idle loop.   As the player types digits, the keypad dispatch collects them.  Once the keypad dispatch sees "ENTER", it "returns" to you by clearing the special controller dispatch and branching after the original call site.  (Again, still in a "dispatch" context.)  

 

5 hours ago, mr_me said:

Do you happen to know what frame rate Auto Racing runs at.  I read exec games drop to 15fps when scrolling is involved.

It steals one interrupt every tick.  So, at the fastest speed setting (DISC), it drops to 15Hz.  The game speed in location $103 is the same (3), but the game itself steals an interrupt from the EXEC by rewriting the vector at $100-$101 every tick, for one interrupt.

Edited June 17, 2020 by intvnut
clarify how decimal input works as an example

[1980gamer]

some more evidence that realistic steering is newer...

https://archive.org/details/Electronic_Games_Volume_01_Number_03_1982-05_Reese_Communications_US/page/n57/mode/2up

 

[+DZ-Jay]

On 10/8/2021 at 7:19 AM, 1980gamer said:

some more evidence that realistic steering is newer...

https://archive.org/details/Electronic_Games_Volume_01_Number_03_1982-05_Reese_Communications_US/page/n57/mode/2up

 

Wait ... "USAC Auto Racing"?

[mr_me]

I don't know where it originated but that magazine from the beginning insisted on calling it USAC Auto Racing, and this article is a couple years after the cartridge came out.  You'd think Mattel had this license on an early prototype.

[1980gamer]

2 hours ago, DZ-Jay said:

Wait ... "USAC Auto Racing"?

I just read past that...  But maybe it was....

https://en.wikipedia.org/wiki/United_States_Auto_Club

 

[+DZ-Jay]

1 hour ago, 1980gamer said:

I just read past that...  But maybe it was....

https://en.wikipedia.org/wiki/United_States_Auto_Club

 

Yes, I figured, but it seems Mattel didn’t get the license to it.  Perhaps they were aiming at it.