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 Using Perlin Noise to generate an infinite world  (Read 6980 times) 0 Members and 1 Guest are viewing this topic.
ahottev

Senior Newbie

 « Posted 2010-12-13 15:09:55 »

So i have this function :

 1  2 `public PerlinNoise(int width, int height, int freq, float persistency,            int density, float sharpness, int detail, float amplitude, long seed)`

It generates me perfectly good Perlin Noise. I'm using it to create a 2d height map.

I just can't seem to figure out how to get an infinite world out of it. Say i generate a 1024x1024 map with it. That's cool, i have a 1024x1024 grid. Now, how do i get past that? If every pixel is a 3d block in-game, how can i calculate past the initial first 1024 ?

SimonH
 « Reply #1 - Posted 2010-12-13 15:26:03 »

Adapt the perlin noise function to take x & z values instead of a seed value, then you can get height data for any x,z location. If you use doubles for x & z you'll get a very, very big (near-infinite) landscape.

People make games and games make people
ahottev

Senior Newbie

 « Reply #2 - Posted 2010-12-13 15:47:31 »

Can't seem to get it to work perfectly.

I have this: (not the complete Perlin code here)

 1  2 `public PerlinNoise(int width, int height, int startFreqX, int endFreqX, int startFreqY, int endFreqY, float persistency,            int density, float cloudSharpness, int detail, float amplitude, long seed)`

 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30 `public void run()      {                        Random r = new Random();                        r.setSeed(seed);         BufferedImage temp = new BufferedImage(endFreqX, endFreqY ,               BufferedImage.TYPE_4BYTE_ABGR);         Graphics2D g = temp.createGraphics();         // generate a low-res random image         for (int i = 0; i < endFreqX ; i++)         {            for (int j = 0; j < endFreqY; j++)            {                                        int val = r.nextInt(255);                                              g.setColor(new Color(val, val, val, (int) (alpha * 0xFF)));               g.fillRect(i, j, 1, 1);            }         }         g.dispose();         // re-scale the image up using interpolation (in this case, linear)         image = new BufferedImage(width, height,               BufferedImage.TYPE_4BYTE_ABGR);         g = image.createGraphics();         g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,               RenderingHints.VALUE_INTERPOLATION_BILINEAR);         g.drawImage(temp, 0, 0, width, height, startFreqX, startFreqY, endFreqX , endFreqY , null);         g.dispose();      }   }`

With these parameters
(256, 128, 0, 24, 0, 12, 8.0f, 120, 0.10f, 5, 0.99f, 1l) i get a 256x128 b&w map.

Now, i want to work in 128x128 blocks. To get the first block, i enter:
(128,128, 0, 12, 0, 12, 8.0f, 120, 0.10f, 5, 0.99f, 1l)

And to get the second block to the right, i enter:
(128,128, 12, 24, 0, 12, 8.0f, 120, 0.10f, 5, 0.99f, 1l)

I almost works, you can clearly see the resemblance, but there's always a few pixels different near the edge. It's not acceptable for map generation.

What is wrong ?
Roquen

JGO Kernel

Medals: 517

 « Reply #3 - Posted 2010-12-13 18:13:21 »

I'll repeat what SimonH said.  You have to feed coordinates, otherwise "edges" of your precomputed regions will not match.  Since you're combining multiple "frequencies" (or zoom/scale levels) of noise, the coordinates must match at all levels.
ahottev

Senior Newbie

 « Reply #4 - Posted 2010-12-14 13:15:55 »

I'll repeat what SimonH said.  You have to feed coordinates, otherwise "edges" of your precomputed regions will not match.  Since you're combining multiple "frequencies" (or zoom/scale levels) of noise, the coordinates must match at all levels.

Ok, I see what was wrong. I was not using a real Perlin noise algorithm, but a function that creates noise by re-scaling a low-res noise bitmap... It's working fine now.
namrog84

JGO Ninja

Medals: 46
Projects: 4

Keep programming!

 « Reply #5 - Posted 2011-03-31 15:58:54 »