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Thursday, 5 May 2016

One step forward, two steps back

Lunchtime bug fix #8, the game crashing after player 1 dies in a 2-player game. There was an issue with the routine that remembers the shields; the game progresses to player 2 now.

However, after player 2 dies, player 1 subsequently dies immediately and their game ends, printing the "GAME OVER" message on the wrong row of the screen. And ditto then for player 2. We'll call these bugs #10 & #11... so currently 8 down, 3 to go.

UPDATE: Well, I guess I've never actually played 2-players on Space Invaders before; turns out the "GAME OVER" message is actually printed at the correct position on the screen; below the shields! What was in the wrong position though, was the bottom line, because the byte value was hard-coded in-line, and I hadn't reversed the bits for it.

So replacing bug #11 with an actual bug (fixed), that's 9 down, 2 (at least) to go! Now to find out why the 2-player game isn't working properly...

UPDATE #2: Again, fixed bug #10 and bug #12 appears - when player 1 starts up after player 2 dies, the invaders aren't erased properly, and eventually the game resets. 10 down, 2 (still) to go. I suspect there's at least one more bug - the 2-player game never ends even after players run out of bases. Could be parasitic to one of the two remaining bugs, but probably not.

Once the two-player game is working, and it's very close now, it's just the bomb frequency, and there's a routine specifically for that. Agonisingly close now!

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