Tiling Systems

Define Tile Corners
===================

A---B
|   |
|   |
C---D

Here, A,B,C,D are given as wall/floor in the map, and we select an appropriate tile for this "boundary" between the wall and floor.

For example A=B=C=wall, D=floor would give a wall corner tile, with floor towards the lower right.

- There is choice whether to have the transition tiles appear as mostly wall, mostly floor, or somewhere inbetween.

- Each tile has four corners, leading to only 16 tile variations.

- Diagonal cases become possible (A=D=wall, B=C=floor). This may be unfavoured, because depending how the transitions are drawn, the diagonals can appear open or closed, and it can be hard to find a comfortable compromise.

- A sequence of nodes Wall-Floor-Wall will create a corridor from a pair of "side" tiles, without a specific floor tile between them. This may be too narrow to walk down if the bulk of the tile is drawn as wall. To prevent this, the wall tiles need to be drawn so that the the floor encroaches considerably into them (about 50%). Visually this may be undesirable. This can also affect the diagonal cases described above.



Define Tile Faces
=================

+-----+
|     |
|  A  |
|     |
+-----+

Here we define solid wall and solid floor tiles.

- If the graphics need to illustrate the sides, then the tile connectivity is "side" based. Four sides means 16 basic variations.

- Unfortunately corners play a role too. eg, a wall tile with four wall neighbours is not necessarily "internal" to the wall. It may still be exposed at any of it's four corners, and be a concave corner piece. Taking all of these internal/concave permutations into account, there are iirc 48 tile variations needed. That's quite a lot to draw.


Tile Quarters
=============

+---+---+
| . | . |
+---A---+
| . | . |
+---+---+

Here we define solid wall and solid floor tiles.

- Each tile is subdivided into quarters, top left, top right, etc.

- The piece used for each quarter is determined by it's the four tiles surrounding that "corner" node. Either: solid floor, solid wall, horizontal boundary, vertical boundary, concave corner, convex corner.

- That is 6 variations * 4 corners = 24 quarter tiles. This is twice as frugal as the previous system. However, remember that these quarter tiles are 1/4 of the size of a full tile, so in actual area it is only 24/4 = 6 tiles-worth of graphics, which offers significantly lower variation than the other tiling systems.

- Unfortunately, ensuring that the corners fit together graphically means that there is less creative freedom for how to draw them.

- The tiles usually appear somewhat bulky and repetitive -- partly because of this lower creative freedom, partly because of the higher tiling density, and partly because there is only 6 tiles-worth of graphics.

- Four times the number of quads need to be drawn to render the map, and the logic of determining which corner pieces to draw is harder.