Tile based map.
by Vladimir
Vasilyev
Part1.
First of all, we restrict possible terrain type position
concerning each other. It means tiles representing different
terrain type may neighbour with one or two definite terrain
type not with all.
Let arrangement is : watergroundgrasstree. Water and
tree may have the only neighbor  ground and grass accordingly.
Pic. 1 :
Terrain precedence ordering from low type (water)
to hi one (tree).
Thus we need three tile sets for
four terrain types:
Set1 for waterground transition  map brush is ground
Set2 for groundgrass transition  map brush is grass
Set3 for grasstree transition  map
brush is tree.
Any tile within some tile set will be determine
by 8 bits  low 4 bits for the edges and Hi 4 bits for the
corners.
The next step is to define direction order,
in which we will check neighbour tiles for the current
selected tile. You may see they on the Pic2 (left) .
Also the bit assignments order for the edges and corners will
be the same. It shown on the Pic 2(center).
Pic.2 : Direction and
checking bit correlation.
Note that for the proper map:
bit 0 equal
bit 2
bit 1 equal bit
3
bit 2 equal bit
0
bit 3 equal bit 1
and so on... because there will be the same terrain type.
For any tile set we have two different
terrain type. One of them we will consider as the Hi
type and other as the Low type.
For Hi type we will set according
bit to 1 and for Low type we will set according
bit to 0.
If you have some difficulties of
bit manipulation  see Bit manipulation demo.
To sum up, we shall present the next common
terrain transition bit model for certain tile set.
Pic. 3 : Common
terrain transition bit model.
You can see the edge and corner
tiles and theirs bit representation proceed in normal binary
manner: 0000,0001,0010 and so on...
We can reduce the number of different tile
type by replacing some tiles as shown on the Pic4.
Pic. 4 : Reduced
terrain transition bit model.
The final tile set for groundgrass is shown
on the bottom.
Pic. 56 : Real terrain
tile set.
Copyright ^{©
}2001 Vladimir Vasilyev.
Any part of
given clause, including illustrations, in any purposes can not
be reproduced in any form and any means without the written
permission of the author.
