Computer Science Canada

collision detection in tetris
Author:  omni [ Mon Mar 08, 2004 5:24 pm ]
Post subject:  collision detection in tetris
I got the rotation down pat, now I need some help on the collision detection.
The current piece is stored as a 1..4*4 array of int .
A '1' says that this place is taken up by a block and a 0 says its free.
The board itself is also one huge one dimensional array 1..12*39 of int
Note these aren't 2 dimensional arrays I want to keep them 1 dimensial.
Author:  McKenzie [ Mon Mar 08, 2004 5:38 pm ]
Post subject: 
Ouch. 2-Dim is the way to go. Ignoring that, you are obviously trying to compare your piece vs the board to find collisions. I assume that you are already restricting the piece so that it can't go off the edges. The check will look something like:
code:
var pieceAt := where bottom left corner is in the board array
var hit:=false
for h : 0 .. 3
    for w : 1 .. 4
        if piece(h*4 + w) + board(h*12 + w + pieceAt) = 2 then
            hit :=true
        end if
    end for
end for
Author:  omni [ Mon Mar 08, 2004 6:20 pm ]
Post subject: 
if I were to change the 1 and 0's to boolean true and false, in order to compare the two I would have to use the boolean operators right?

ex:
OR XOR AND ?
Author:  Tony [ Mon Mar 08, 2004 6:46 pm ]
Post subject: 
as oppose to not using and/or ? Confused
Author:  omni [ Mon Mar 08, 2004 7:34 pm ]
Post subject: 
what do you mean?
Author:  Tony [ Mon Mar 08, 2004 7:39 pm ]
Post subject: 
ohh... I think i get what you mean by boolean operators... and you could use them... you can also use if = comparison.
Author:  omni [ Mon Mar 08, 2004 8:02 pm ]
Post subject: 
ya thats what I was planning to do with them. using in if statement,
but still having trouble
Author:  McKenzie [ Tue Mar 09, 2004 8:35 am ]
Post subject: 
ya, you would use AND because you only care about the case where the collision occurs.
Author:  omni [ Tue Mar 09, 2004 5:41 pm ]
Post subject: 
thanks sir, err.. McKenzie
Author:  omni [ Tue Mar 09, 2004 8:45 pm ]
Post subject: 
here is my program so far, bugs are evident, but I just want to get some opinions and whether it is worth programming for the People.

edit: has someone else previously made a tetris game like mine?

Ctrl and ALT are to rotate and 'j' and 'l' to move left and right
Author:  Paul [ Tue Mar 09, 2004 8:58 pm ]
Post subject: 
hm, a couple of bugs, the next piece appears in the x coordinate of where the last peice fell. When you turn it near the edge, it goes all wacky. The piece rotates funny (or does it?) oh, and I can turn it when there isn't space.
Author:  omni [ Tue Mar 09, 2004 9:03 pm ]
Post subject: 
i've got the first few problems fixed, but the detection of whether the piece has enough room to rotate or not is going to be hard.

Note: if I can get the bugs fixed, should there be a cooperative mode, or vs or both?

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