Creating a Tycoon Game Part 1 - Writing the ISO engine

For that Business Simulation Game I am working on, I decided to go with an isometric view of the buildings. 3D would have been possible too - especially since I am also working on that 3D game engine - but I think it is much easier to place buildings and have a nice overview with an isometric 2D view.

Programming wise, it is a mixture of 2D and 3D, and you have a combination of the disadvantages and benefits of both: Mostly everything is nearly in screen coordinates but you still need to do some z-sorting and clipping. It's easy to implement, even calculating the position of an iso-tile is very easy (pseudo language):

getIsoTileScreenPosition(x, y)

{

   var tileWidthHalf =  isoTileWidth  * 0.5 * zoom;

   var tileHeightHalf = isoTileHeight * 0.5 * zoom;

   

   return position2D( x * tileWidthHalf  - y * tileWidthHalf, 

                      x * tileHeightHalf + y * tileHeightHalf );		

}

I've written about 5 isometric engines during the last 20 years, in Delphi, Basic, C, ActionScript and C++. But none of these had zoom, which I definately need for this game. I experimented a bit, and after a while I felt that I found a very nice way to do it: The engine is able to zoom smoothly, but the user only can switch between 5 or 6 fixed zoom steps. This makes the world and game feel very responsive: It looks very nice when zooming is moving between two fixed steps, and the user is still quickly able to switch between two or more of his preferred zoomed views:


I'm satisfied with how this worked out so far. I'll post a new update next week.
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