# Thread: Procedural world generation - ground and traps seems to not generating.

1. ## Procedural world generation - ground and traps seems to not generating.

I've got my terrain generator to working, but bad thing is it seems to not generate ground blocks and spikes even though it should.

Here are functions responsible for generating ground and spike blocks:

Code:
```function TWorldGenerator._genStepGround(Chunk: TChunk): TChunk;
var chunksize,x,y:Integer;

begin
chunksize:=Length(Chunk);
for x:=0 to chunksize-1 do begin
for y:=1 to chunksize-2 do begin
//we start at Y=1 and end one index before end of chunk as we need to test block before that for being
//air and if there is something under.
if ((Chunk[x][y]=AIRID) and (Chunk[x][y-1]=AIRID) and (Chunk[x][y+1]=GROUNDID))
then Chunk[x][y]:=INVINCIBLEBLOCKID;
end;
end;
result:=Chunk;
end;

function TWorldGenerator._genStepTraps(Chunk: TChunk): TChunk;
var chunksize,x,y:Integer;

begin
chunksize:=Length(Chunk);
for x:=0 to chunksize-1 do begin
for y:=1 to chunksize-2 do begin
//we start at Y=1 and end one index before end of chunk as we need to test block before that for being
//air and if there is something under.
if ((Chunk[x][y]=AIRID) and (Chunk[x][y-1]=AIRID) and ((Chunk[x][y+1]=GROUNDID) or
(Chunk[x][y+1]=INVINCIBLEBLOCKID)) and (Random(101)<TrapChance)) then Chunk[x][y]:=SPIKEID;
//randomizing above is so whole ground won't be in traps.
end;
end;
result:=Chunk;

end;```
And here is whole world generation unit (pastebin since it is quite big): http://pastebin.com/fLFjsC8Z

ChunkUtils is simple unit that contains only function that draws circles in chunk (for carving cave - carving step happens before generating blocks and spikes, so that isn't a problem). boolUtils is unit with just one function that checks if value is between two values. Nothing too fancy. Also don't worry about functions that doesn't return values - they're just stubs and aren't implemented yet.

2. can you explain to me how it works? (because in the process you'll probably find the bug yourself )

3. Originally Posted by Darkhog
I've got my terrain generator to working, but bad thing is it seems to not generate ground blocks and spikes even though it should.
What exactly goes wrong? It generates in a way you not expected or just not generates anything?

4. First thing i would do is clarify the program with small change, maybe causing it to speed up in the process. Dynamic array might be reference-based by default, but i don't think it becomes very clear with this:
Code:
```function TWorldGenerator._genStepGround(Chunk: TChunk): TChunk;
function TWorldGenerator._genStepTraps(Chunk: TChunk): TChunk;```
You are passing a big array as parameter, and returning one aswell. You could simply refer to it, apply changes to it directly (because that's what already happens, right?), so:
Code:
```procedure TWorldGenerator._genStepGround(var Chunk: TChunk);
procedure TWorldGenerator._genStepTraps(var Chunk: TChunk);```
These would change too:
Code:
```_genStepTerrain(Chunk);
_genStepCarve(Chunk);
_genStepGround(Chunk);
_genStepBlocks(Chunk);
_genStepTraps(Chunk);```
I'm still pretty "new" to perlin noise, but aren't you supposed to combine many random waves. First ones smooth big ones, then smaller and sharper. From line 99+, you are using same frequency for all of them. Do i just misunderstand the code?
Could be the PerlinNoise2d() already does the multi-wave math for you.

5. Originally Posted by User137

I'm still pretty "new" to perlin noise, but aren't you supposed to combine many random waves. First ones smooth big ones, then smaller and sharper. From line 99+, you are using same frequency for all of them. Do i just misunderstand the code?
Could be the PerlinNoise2d() already does the multi-wave math for you.
it is my understanding that PerlinNoise does all that for you which is why it is so slow to begin with.

6. @Darkhog

You can set size of dynamical multidimensional array using SetLenght(array, XDimension, YDimension).
http://stackoverflow.com/questions/5...ensional-array

Also why not storing chink IDs in nuerical way. So you can have soething like this:
Air = 1, Water = 2 and all ground chunks have ID higher than 2.

So spike placment code would look something like this:
Code:
`if ((Chunk[x][y]<3) and (Chunk[x][y-1]<3) and (Chunk[x][y+1]>2) and (Random(101)<TrapChance)) then Chunk[x][y]:=SPIKEID;`
With this you get rid of yourself of that or statment. And becouse you would probably have multiple ground types in the future you saves yourself the need for checking each posib le ground id in the first place.

I would also split that multicondition if statment of your into several nested if statments. Why? When you are using multiconditional if statment all conditions get checked even if first condition isn't met already. So using nested if statments could speed up your code a bit since it won't be ckecking if other conditions are met, when the first condition has already failed to meet the requirements. Not to mention that such code would be more readable.

7. Originally Posted by laggyluk
can you explain to me how it works? (because in the process you'll probably find the bug yourself )
Sure! First program generates ground using Perlin noise, then it carves cave then it is supposed to place grass tiles (INVINCIBLEBLOCKID) and traps but it doesn't work.

@SilverWarrior: Yeah, I thought so about setting dimensions bu wasn't sure. Will change that bit of code. Also let's say I'd make 2d minecraft (which isn't something I want to do): Grass can only grow on ground, so it is unlikely I'll need to check for other ground tiles, especially in Super Heli Land where it is like 3-4 tiles max.

@User137: Thanks. But that is optimization part. I need first to make my code WORK. After that, I'll do as you say.

8. Originally Posted by SilverWarior
When you are using multiconditional if statment all conditions get checked even if first condition isn't met already.
This is not true. I can demonstrate that with simple example:
Code:
```var sl: TStringList;
begin
sl:=nil;
// Version 1: No errors
if (sl<>nil) and (sl.Add('Test')>0) then exit;

// Version 2: Runtime error
If-statement ends in the (sl<>nil) condition, because any further conditionals wouldn't change the logical end result. If there was OR, instead of AND, then it would have to proceed to next comparison because (sl<>nil)=false.

edit: Have you double/triple-checked the drawing code, or done analyzing to the chunks to see if traps are actually generated, just hidden.

9. OMG! Found issue. I was using byte for array of TChunk and AIRID was defined by -1. Me and my stupidity... Now it works nicely.

//edit: When I set chunk x/y when generating world to other number than 0, it generates same exact chunk no matter what I do .

//edit #2: This is most current version of my world generation class: http://pastebin.com/sPsfNWLD. I've applied optimization fixes suggested by User137 and SilverWarrior, but it is moot point since it generates exact same chunk no matter of what value I put into chunk x/y.

10. Ok, I've figured what issue was: It turns out that I had to first generate one chunk before generating subsequent ones. I've also found out that ChunkX and ChunkY does nothing. WTH? Problem with chunks not adding up (seams) probably lies in carving step, however I don't know how to fix it.

Problem with ChunkX/ChunkY doing nothing... Well I don't even know what causes it (here's perlin noise unit I'm using, which might be relevant - I didn't wrote it nor I do understand it: http://pastebin.com/CSk62Jdf).

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