Is there an inbox delay?

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subotai
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Is there an inbox delay?

Post by subotai »

Hi,

I remarked that in different games the time when you can start moving after you have started playing a cave may differ. I wonder what it depends on, the engine, the cave delay or both? Could anybody help me, please? I need to calculate the number of frames until the player can move.

Thanks
subotai
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LogicDeLuxe
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Post by LogicDeLuxe »

You can calculate an aproximation by assuming 2 seconds for NTSC and 2.4 seconds for PAL games. But unfortunately, things are more complicated that this.
From my memory, which hopefully serves me right:
The timer is set at the beginning of writing the cave into RAM. At that time, the screen is fully covered with those scrolling steelwall pieces. 120 TV fields later, the cave scan begins, unless the writing of the cave is not finished yet, which can happen in BD1, BD2, CrDr engine games, or mazes in Crazy Dream 9.
After 240 TV fields, the inbox stops flashing and Rockford is hatching from the empty state. In the worst case (insanely slow cave design assumed), the start signal may occur even before the cave scan starts, so the inbox will not flash at all.

You probably already noticed by now that this entire timing is rather wacky, so that you can not assume any precise frame count. The bonus life effect delays the cave scan slightly, so Rockford may hatch a frame or two earlier. Pressing space to pause the game may also delay the scan slightly. The different refresh rates between PAL and NTSC makes this even worse.
But that's not all. For some very odd reason, BD1 and PLCK added another 120 TV fields delay when in 2-player-mode. At least in PLCK, it can be considered a bug, since there is no way to test a cave this way in the editor. This bug was fixed in my Deluxepacker 1.55.

XDC introduces reliable timing to Boulder Dash on the C64.
subotai
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Post by subotai »

Thanks for your reply. That's what I suspected. In most caves I doesn't matter if the, let's say "inbox delay", isn't accurate. But in others you could get hit by an enemy before you have a chance to move. I already analysed some games. So I try to find an approximate value for this.

subotai
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