Batari Basic peculiar

[MissCommand]

Hello all,

 

Slowly working on my game (decided on name... Mall Rush!) and having a very peculiar problem. Been staring at this a few days now and before totally rewriting to find a different way to code, thought I would see if anyone had a solution (or explanation):

 

Using DPC+. I have sprites "falling" and my player0 at the bottom dodging. I have a special sprite (player7) that I want to collect and not dodge. Distilled below:

 

So when I detect a collision:

 

Main loop:

 

;*** Check for collisions

if collision(player0,player1) then goto _End_Coll

_Return_CollGift

continue

_End_Coll

if player7y > 149 && player7y < 166 then gencount = 1 else goto _Return_CollGift

score = score + 200

Ch0_Sound = 5 : Ch0_Duration = 1 : Ch0_Counter = 0 ; Play Adventure Grab

goto _Return_CollGift

This works great for testing... It detects the player7 position on my bottom row and adds score and plays sound.

So now when I actually want player0 to lose a life when colliding with anything else I just redirect the goto to a differnt location instead back to the main loop:

_End_Coll

if player7y > 149 && player7y < 166 then gencount = 1 else goto _End_Life

score = score + 200

Ch0_Sound = 5 : Ch0_Duration = 1 : Ch0_Counter = 0 ; Play Adventure Grab

goto _Return_CollGift

_End_Life

do stuff

goto _Return_CollGift

And now every collision is sending me to _End_Life! Im not sure how changing a goto location is causing my if statement to work different and not evaluate player7 position correctly.

I must be doing something dumb and just not catching it.

Help!

Edited September 29, 2017 by MissCommand

[+Karl G]

Without seeing the rest of your source, I can only make a guess, but the first thing I would suggest trying is renaming your _End_Life label to not have the word "end" in it. I've had issues with labels containing keyword before.

[+atari2600land]

The problem with the "end" in a label is if it's the first word in it. Something like "please_end_coll" would work.

[MissCommand]

Thanks for the suggestions guys! As RandomTerrain and others suggest, I do use underscores in front of all my labels.

 

After much aggravation I finally realized the problem. The collision routine is actually being called TWICE because I did not remove player7 completely from my internal list. The first time through it works correctly, but I did not notice because the "partial" remove I did called the collision to work opposite the second time... so I did not notice the first pass through. I finally realized what was going on when I noticed the score was being incremented even though it was not supposed to. Ugh!

Edited October 2, 2017 by MissCommand

[MissCommand]

Actually, after more testing that was only partially the problem... ugh! Can anyone tell me how to monitor the numerical position of a particular sprite? Either through setting the score or through the Stella debugger?

 

Thanks!

[+Random Terrain]

Actually, after more testing that was only partially the problem... ugh! Can anyone tell me how to monitor the numerical position of a particular sprite? Either through setting the score or through the Stella debugger?

 

Thanks!

You mean like what is in these example programs?

 

randomterrain.com/atari-2600-memories-batari-basic-commands.html#testvariables

 

randomterrain.com/atari-2600-memories-batari-basic-commands.html#find_border_coordinates

 

randomterrain.com/atari-2600-memories-batari-basic-commands.html#ex_multisprite_9_objects

 

randomterrain.com/atari-2600-memories-batari-basic-commands.html#ex_dpc_13_objects

[MissCommand]

You mean like what is in these example programs?

 

randomterrain.com/atari-2600-memories-batari-basic-commands.html#testvariables

 

 

Exactly like your first link! Thanks!

 

It did reveal something really interesting... the collision detection appears to be happening a few pixels above where I think it should be. My sprite starts at y-position 150 (16 pixels high), but the collision triggers start at y-position142. Strange.

Edited October 4, 2017 by MissCommand