ned Productions – Flow

by . Last updated .

Flow is a simple game for Win32 based machines based on a cellular automata algorithm which mimics the properties of a liquid. It is not a game with an object or goal like most eg; like scoring points or killing something, but it is rather more like a toy which exists merely to be fiddled with. A good example of something similar is a game used by many charities where coins inserted at the top fall through the game, hitting off things as they go. Where Flow improves on this is that the obstacles can be changed in real-time, with the liquid responding accordingly.

Real-life scenarios such as waterfalls, fountains and showers can be represented - or indeed anything your imagination allows. User-triggered events can be designed (eg; flushing a toilet) through a user-toggleable filter material. Devices such as capillary action (where liquid in a vertical narrow space tends to rise) and water pumps (up, left and right) move the liquid around the game area in a more controlled fashion. There are two different kinds of liquid, one lighter than the other if user-desired and two tools to filter one type from the other.

To give you some idea, here's a screenshot:

System requirements:

  • Microsoft Windows 95, 98, NT 4, 2000 or XP with DirectX 3 or later installed where necessary
  • A Windows-supported pointing device (eg; mouse, trackerball)
  • A DirectX accelerated video card (preferably AGP or PCI66 based) will make the game much more useable especially in non-256 colour graphic modes

Recent happenings:

  • Added 11th October 2006:
    Released v1.11. Fixed incompatibility with Windows XP and non-administrator user accounts. Added GDI-only blitting option. Added vertical refresh syncing to greatly lower CPU usage.
  • Added 19th June 2002:
    Released Flow as free software under the GNU Public Licence.
  • Added 28th October 2000:
    Flow v1.1 is finished! I apologise for how late it's been, I had intended to have it finished before I moved permanently to Madrid, Spain but it kept getting pushed to one side (never mind one pernicious bug which took three weeks to fix). Anyway, with only days to go before I start full-time work again, here is v1.1 of Flow!

    Flow v1.1 contains many user-suggested improvements, bug-fixes and additional features:
    • There now can be two types of liquid molecule, normal & light. Light molecules float above normal ones if liquid densities is turned on. You can add as much of either type or mixed as you wish.
    • Molecules can now be of any user-defined colour and this setting is held in between games
    • There are three new tools, Filter (gray), Normal Filter (light blue) and Light Filter (light red). The last two filter out normal and light molecules respectively. The first behaves as a normally drawn line but can be made to effectively "disappear" by pressing the Space bar.
  • Added 9th July 2000:
    Well, a few copies have been bought and are now out there! I've already had some feedback from them and from the review by ZDNet, whose listing and review of Flow is here!

    Anyway, this has led to work beginning on the next version of Flow, v1.1. Currently slated additional features include:
    • Two types of liquid (red and blue), one being optionally "heavier" than the other
    • Three new tools, Filter, Red Filter and Blue Filter. The first can be used to set up a scenario (eg; a tank filling up) and then when the player wants to empty the tank they can toggle a switch which makes the filter material invisible. The latter two do as they say, they are invisible to one type of molecule but not the other
    • As per ZDNet review suggestions: (i) add demo files to menu structure and (ii) add user-configurable colours. The latter was coming anyway as I already have code in there to handle it - just no user-interface yet.

    I've also had the suggestion of a "shower head" tool which would be nice as doing it manually dot by dot is annoying. Maybe, we'll see!

    Remember that all registered owners of Flow will receive this new version in their email as soon as it's ready!

  • Added 4th July 2000:
    Games has been finished and placed on sale! Yipee!

The most recent version of the game is v1.11!

Recent issues:

  • Added 19th June 2002:
    On my new computer, Flow locks up the machine or exits immediately with a general protection fault. I don't know why this should be, it's when it creates the DirectX surface so that suggests a video card driver problem. It works perfectly on my old machine.

    Anyway, my spec is dual Athlon with ATI Radeon All In Wonder. Let me know if you have similar problems.
  • Added 4th July 2000:
    On some video driver versions on Windows NT 4.0 (with Service Pack 3 or later), a 256 colour surface cannot be used in non-256 colour modes. Flow has a check for this and will ask you if you wish Flow to temporarily switch to a 256 colour mode.

    One issue with this is that the check is redone whenever you load a game. This will causes the screen to revert to the original mode and then reask if you want to switch into a 256 colour mode.

    It is hoped that the source of these problems on NT4 will be identified soon and fixed. Until then, our apologies.

    Note that Flow does not have this problem on Windows 2000.


Win32 Binaries and Manual only (172Kb)

Complete sources under the GNU Public Licence (244Kb). I would appreciate it if you let me know of any improvements or derived works.

You may review an online copy of the game's manual here (v1.11)

Report a bug:

If you feel you have found a bug, please fill out this form.

Contact the webmaster: Niall Douglas @ webmaster2<at symbol> (Last updated: 2000-06-03 00:00:00 +0000 UTC)