Under the Microscope: Quake v0.819

A new “65% complete” version of Quake for Saturn was recently made available by Saturn enthusiast vbt. I know what you’re wondering: does it have any cheat codes?

The answer is: yes, and they’re different from the ones in the final version. Let’s take a look…

The function at 06025d10 executes when the game is paused. At the top of that function is some logic that checks:

• Whether you’re on the Options screen.
• Whether you’ve just pressed L+R+C.
• Which menu item is currently being highlighted.

If you pause, select Options, and then press L+R+C with Customize Contols highlighted, PAULMODE appears in the corner of the screen:

As in the final game, this makes you invincible. The 4-byte value at 0604f5d4 gets set to 1, which gets checked when you take damage. If it’s nonzero, your health won’t go below 100:

If you press L+R+C with Reset To Defaults highlighted instead, you’ll get a full set of weapons:

This works by setting bits on the 32-bit flag fields at 0604f5e0 and 06064810.

Highlight Music Volume and then press L+R+C to restore your health back to 100:

Health is stored in the 32-bit value at 06064820.

If you highlight Sound Volume and then press L+R+C, you get all runes. There’s a different code for this in the final game that makes an “All runes added” message appear onscreen, but this doesn’t happen in the prototype:

Like the “All weapons added” cheat, this updates bits on the flag field at 06064810.

Highlight Lookspring and press L+R+C to enable a framerate counter:

This changes the 32-bit value at 0604f5d8 from 0 to 1. There’s no equivalent effect in the final version, making this the one unique prototype cheat.

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Outro

Some ending notes:

• Many thanks to vbt for making this build available for study — I love it when we get new Saturn games to look at.
• Alert Sonic Weekly listeners will notice that I promised an article on Mighty Hits this week. That one got bumped for this new Quake build. Look for it next week!
• This version of Quake was made by Lobotomy Software. Last year, they put the source code for the engine on GitHub — check it out if you’re interested in that sort of thing.

Thanks for reading; I’ll be back with more soon.