Elegantly tile transition blending

Hi everyone!

I'm working in a tile based game that uses OpenGL and QUADS to draw each tile.

In these two images you can see an example:





You can see that there is a ground and water tiles, each one with its own texture. Also there are different gradient colors depending of the depth or altiture of the tile. The red square is a provisional cursor.

The game background logic works with bidimensional array of tiles.

Here is a full capture without zoom:



You can see the game has a retro/ugly style that I want to change. At least, I want to beauty that squared-as-a-hell tiles with some transition between them.

There is some taken into account options:

1. I can try with a good tileset like this:


Source: http://forums.tigsou...hp?topic=9859.0

And change the tile's texture depending of the neighbor tiles. But... I want a very high variety of tiles and texture, so the combination of them could be in a ver high and complex tileset.


2. Multi-texturing the tiles:

I can mix texture in one tile, but I have no idea how to do it and have a nice result...

The ideal approach is to do something like this:



Of course, I must take in care the 4 corners.

But I only know to do something like this:



:-(


3. My last idea was embrance the retro style and leave the tiles as they are.



Any suggestion or idea for a good looking tile map?

I tried with some terrain tutorials, but they are never based on tiles or texture per tile that I want.

I think the idea is near to the multitexturing and blending, but I have not too much idea about multitexturing and different types of blending :-(