Trouble porting liquid simulation to Pascal - AARRGGHH!

[paul_nicholls]

I thought I should have a look at your code to see what I did wrong, but I am looking at your code and I don't get it. What code is working? I am looking in SimCompression_pde.pas, and it looks like... well, I must be looking at the wrong place because this can't be Pascal code:

if ( blocks[x][y] := GROUND) then continue;

That can NOT be a conversion of

if ( blocks[x][y] == GROUND) continue;

No, I must be looking in the wrong place. Is your archive really your working version? If it is, where is the code for the simulation?

I also note that if I change "continue" to "cycle" in my code, my code seem to get slightly closer to correct, so is really "continue" the same in both languages?

Ah! I know what is going on...the SimCompression_pde.pas file is a partially converted version which I forgot to delete - it is not used, sorry about that!!

The files you need to look at are the units\unit_liquidsimulator.pas file, and of course the xeEngineTest.dpr file too

Continue I think works the same in both languages, at least my code gives the same visible results...what does cycle do? I haven't heard of that one

It seems to be working somewhat, but there are 3 issues i can come up with
- The timer is very heavy on cpu, using full capacity of 1 core.

hmm...interesting, I just ran it on my machine here (Win XP, Intel(R) Core(TM) 2 Quad CPU (@2.83GHz, 3.48GB RAM) and it does't come close to hogging one core.

- Air pockets are filled with water coming from below. The pressure should in physical world limit water flow to only down and sideways, as it is implemented in many games too.

LOL The only game I remember playing with fluids is Terraria, and ok that does work only down and sideways as you said...but I quite like the way the 'pressure' pushes liquid up again as that is what I would expect to happen

It could easily be changed though

- The simulation goes through every tile on screen per game tick. It may work with small mapsizes but when it comes to larger and pixelmap, it would hog all resources. This is why i suggested particle based approach earlier in this thread, which would be very high performance.

Ok, it could definitely be made more efficient. Perhaps I could use a particle (pixel) based approach that you mentioned earlier, but that would be harder to draw wouldn't it? With the current version, you just draw some tiles (which also fits in with how a game I am writing is done too)...

Other ideas would be to have a separate list of tiles with pressures in them which you process instead of the whole map, and only process their neighbours too in the map when needed...that should be much quicker.

Hmm...I could also convert the current version to use fixed-point math too, that might may things quicker too

cheers,
Paul