OpenEuphoria

Collision Detection.

• Posted by "Lucius L. Hilley III" <lhilley at CDC.NET> Apr 23, 2000
• 375 views

Warning: Fixed width font required to see the 2d MAP.

I am working with Cells and SubCells.
Take for example the following tiny 2D map.

<PRE>--Vain attempt to force fixed width. :)
1234567
#######
#  #  #
## # ##
#  #  #
# ### #
#     #
#######

</PRE>

Every # is a wall and every space is open floor.

Each # and space is a cell.
Each cell is represented as taking up 4x4 SubCells.
Thus, CellSize = 4.
In other words.  The above map is internally represented
as this next map.

<PRE>--Vain attempt to force fixed width. :)

############################
############################
############################
############################
####        ####        ####
####        ####        ####
#### p      ####        ####
####        ####        ####
########    ####    ########
########    ####    ########
########    ####    ########
########    ####    ########
####        ####        ####
####        ####        ####
####        ####        ####
####        ####        ####
####    ############    ####
####    ############    ####
####    ############    ####
####    ############    ####
####                    ####
####                    ####
####                    ####
####                    ####
############################
############################
############################
############################

</PRE>

Within each cell a player can in any one of 16 places.
I use {x,y} to represent the position of a player.
player positions are zero based.
There is a 'p' in the above map.  It's {x, y} value is
{6, 7}..  this means that
x = 6 -- and
y = 7

I calculate positions as follow:
--Actually, I use an optimized set of equivalent calculations

XCell = floor(x/CellSize)
YCell = floor(y/CellSize)
XSubCell = x - (XCell * CellSize)
YSubCell = y - (YCell * CellSize)

Keep in mind that the player can make diagonal moves.
My goal is to have the player navigate the maze a bound by
the walls.  My current collision detection works quite well
but is apparently flawed.

        Lucius L. Hilley III
        lhilley at cdc.net
+----------+--------------+--------------+
| Hollow   | ICQ: 9638898 | AIM: LLHIII  |
|  Horse   +--------------+--------------+
| Software | http://www.cdc.net/~lhilley |
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