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Representing Bitmaps for Hex Grid?

BlitzMax Forums/BlitzMax Programming/Representing Bitmaps for Hex Grid?

zoqfotpik(Posted 2014) [#1]
Let's say someone was writing a game similar to the old Civilizations which used 2D bitmaps for the hexes.

What is a good way to draw a hexagonal bitmap in Blitzmax? One obvious way would be to atlas them packed onto squares with transparency color between but that leaves a fair bit of wasted space. Is there any more efficient way?


Derron(Posted 2014) [#2]
More efficient in storage, but less in drawing:

    .^.         .^.            _____
   /   \  -->  /___\   -->   |\\   //|     ___
  /     \     /|   |\        | \\ // |    |   |
 /       \   / |   | \       |  -'.  |    |   |
 \       /   \ |   | /       |  '.'  |  + |   |
  \     /     \|___|/        | // \\ |    |___|
   \   /       \   /         |//___\\|
    \ /         \ /
     '           '

1. your tile
2. an imaginary cutline
3. the outer triangles cut and reversed (left triangle gets right one, top gets bottom one etc.)
4. the center tile of the sprite - the rectangular area.


Hope my drawing is understandable.


Another thing would be some kind of "rotation" or quad-manipulation- All in all I think the way to keep the sparpness of the bitmaps is to store them as they are (or packed like I explained above).


bye
Ron


Calibrator(Posted 2014) [#3]
More efficient in storage, but less in drawing:

Exactly.

I think one should have *very* good reasons to abandon the "traditional" transparency method and the simpler drawing/storage routines, that are also easier to maintain.
Here are some questions one should be able to answer:

- How many hexagonal tiles are really needed? Dozens? Hundreds? Thousands?

- How much memory do you want/need to save? A few megabyte? Or drastically more?

- What platform do you develop for? Regular PC/Mac platform? With how much gigabyte RAM (of HD storage space and RAM)?

With most graphics cards of the last six, eight years you can use tile images with a resolution of 2048x2048 *easily*. You can put 1024 tiles with a resolution of 64x64 pixels into those.
If you want to be even more compatible (to older hardware) then use a resolution of 1024x1024 pixels which still means 256 tiles with that dimension - with each of those "megapixel files".

Hope my drawing is understandable.

Yes, your drawing is very clear - but it doesn't show hexagonals... ;-)


Derron(Posted 2014) [#4]
lol ...you are right, it shows iso-tiles (thought he wanted to say that because "old Civilization" is Civ1 or Civ2, first one had normal tiles, second one iso tiles).


But the principle stays the same: each "cut of corner" could be merged with the oposite ones of all corners.



bye
Ron


zoqfotpik(Posted 2014) [#5]
Makes sense, thanks gents. I keep forgetting that we have supercomputers now.