SCI: PQ4: Spaceship collision with asteroids not working

[bgK]

ScummVM: 9f055d4ba12e809abab41ab1b7af1794eb75a1f6
Game: DOS / CD / French / Hi-Res

During the third day, Carey can go back to the Short Stop bar. When he uses his change on the arcade cabinet an Asteroids like minigame starts. The game plays fine, but asteroids go trough the spaceship without collision, making the game almost impossible to loose. Since loosing seems to be the only way to exit the game, I'm stuck playing Asteroids. Help ;)

To reproduce, load the attached save, and use the change on the arcade cabinet.

[bgK]

Save (French version)

[bluegr]

The scene in question is 2010.

This probably the only SCI32 game which actually uses the kObjectIntersect kernel function, in this particular scene.

The issue is that our current implementation of this function uses SCI16 code, and yields wrong results. I'm attaching a patch that is what the original SCI21 interpreter is doing. The function itself works fine, however sometimes there's an assertion thrown in celobj32.cpp:325, in READER_Compressed, function getRow(), but it looks to be random.

I've also managed to reproduce an uninitialized read error when I died once while an enemy ship was present:
Uninitialized read for temp 7 from method enemyShip1::cantBeHere (room 2010, script 2010, localCall ffffffff)

[bluegr]

Proper implementation of kObjectIntersect

[bgK]

Thanks. Your patch also fixes the "sand buggy" arcade game on the right.

[bluegr]

Thanks for your feedback! I've made a pull request with the fix for this:

​https://github.com/scummvm/scummvm/pull/964

[wjp]

This should now be fixed by commit 820caf370e2c24e6aefd8b1b90227ca29564bab6. Thanks for catching this!