Digit 7

Introduction

     When I first started in XNA, I made a program that would take in heightmaps and create terrain. I had to download a lot of different heightmaps online, but they only came in certain sizes and some had poor resolution which made for terrible looking terrain. Plus the concept of how they were created always intrigued me, so I investigated the matter myself and wrote a C# program to generate heightmaps based on Perlin noise. I create the terrain by summing up several 2D Perlin noise functions using different amplitudes and frequencies. If you go to my Links page at the top, you'll find some references which do a great job explaining how Perlin noise works and gives plenty of good examples on how to implement it.

How to Use It

     The whole thing is pretty simple to use. I created two classes: PerlinNoise2D and HeightMap. The Heightmap class is the one you'll be using. I wouldn't mess with the PerlinNoise2D class unless you know what you're doing; there's a lot of tricky code in there and it's not very well documented.

     I gave you two ways of creating a heightmap:

1. Use the included UI with it. All you have to do is enter in the full filename with extension, the width and you're good to go. If you want to integrate it into your own program, the next two steps discuss the methods I exposed which you can use.
   
2. Use Heightmap.saveHeightmap(). This will save your heightmap to a RAW file. It asks for the width in pixels, the height in pixels, how bumpy you want the terrain to be, and finally the filename. Keep in mind the filename is the whole filename, extension included ( Examples: "C:/test.RAW", "C:/Program Files/HeightMapGen/myheightmap.RAW" ). After you run that method, go to that location and it will spit out your file. My favorite RAW image viewer is IrfanView, which is very powerful tool (did I mention it's 100% free?)
3. Use Heightmap.generateByteArray(). Same in the same parameters as saveHeightmap() except no filename this time. This will return a single-dimension array of bytes, each one holding a pixel color. You can use this if you want to generate your heightmap on the fly and not use it in a file.

How to Tweak It

     The only function you really need to play around with is the Heightmap.generateByteArray() method I just mentioned. This is where it creates the different Perlin noise functions. Modifying what parameters you use for your Perlin Noise functions will allow you to change what type of terrain it will generate.

- If you want large, rolling hills, use smaller frequencies and larger amplitudes.
- If you want a really jagged terrain, use higher frequencies and larger amplitudes.
- If you want small hills, use higher frequencies and small amplitudes.

     Play around with it! See what results you can get. It's a very flexible system.

How to Make It Better

• Probably the biggest thing you can do is put smoothing into the Perlin noise function. Right now I have none of that so your terrain might have some jagged spots. This is a little more in depth than I wanted to get, but if you do get this implemented, let me know and I'll post the code up here and give you credit for it.
• Be able to make non-uniform heightmap sizes. Right now it has to be a square.
  

     I've provided both the XNA project and executable below in case some of you visiting the site don't have XNA installed. All of the key binds are displayed for you so it should all be pretty self explanatory. If you have any questions, email me at dan@digitseven.com.

DOWNLOAD HeightmapGenerator HERE
DOWNLOAD HeightmapGeneratorEXE HERE