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Posted 26 May 2006

# Managed DirectX Tutorials: Part 7 - Using Heightmaps

, 26 May 2006 CPOL
 Rate this:
Here it really gets interesting - you will add height values to your vertices

## What Are Heightmaps and How To Read Them

In this (rather short) tutorial we will learn about heightmaps, and use them to add different height levels to our vertices to create a realistic-looking terrain.

## What is a Heightmap?

A heightmap is a file used by game programmers to read height data.
In form, they are an image file, usually with as many pixels as the amount of vertices in the game world.

They only have greyscale colour. The program loads this heightmap into memory, and tests the colour value of each pixel. If it is pure white, (255), then the height of the vertex at that pixel location will be the highest (this is usually 255 scaled down by a factor), whereas if it is black it is at the lowest position.

For simplicity, heightmaps are often saved in the .RAW file format.
This is an image format which just stores the pixel data, without any compression or anything else.

These can be opened in image editors such as Adobe Photoshop Elements, and work in a similar way to bmp.

#### How will we apply it to our terrain?

To apply a heightmap to our terrain, we will simply modify the `SetGrid() `method we created in the last tutorial to accept a 2D array of points (which we will apply to the Z-axis) and then create a new method to load the height data into it.

```public int[,] heightFromFile(string pFile, int WIDTH, int HEIGHT)
{
int[,] HeightData = new int[WIDTH, HEIGHT];
FileStream fs = new FileStream(pFile, FileMode.Open, FileAccess.Read);
int Currheight = new int();for (int i = 0; i < HEIGHT; i++)
for (int y = 0; y < WIDTH; y++)
{
HeightData[WIDTH - 1 - y, HEIGHT - 1 - i] = Currheight;
}
r.Close();
return (HeightData);
}```

The first four lines of this method are just setting it up.
`FileStream `opens a link between the program and a particular file (in this case, the one passed through parameter `pFile`), and `BinaryReader `"attaches" itself to this stream so it can literally read the values of the `heightmap`.

We then loop through the file, reading the current byte value (`ReadByte`) and dividing it by two. This gives us a value out of 255, and then the division is simply to scale it down (we do not want our terrain to be able to be that high).
We then assign this value to the appropriate `HeightData `element.
Finally, we close the stream between the file and return the `HeightData `array, now full to the program.

Next, change the `SetGrid()` method so that it accepts a 2D int array called `heightData`, and replace the line:

`CV[y, x].Z = 0;`

with:

`CV[y, x].Z = heightData[y, x]; `

Finally, we can use the `heightData `member of the `Form `class in the previous sample, and load it using our new methods.
If everything went well, you will have heightmapped terrain when you run the sample. :)
Next, we will learn to move around this terrain.

## Feedback

I am always open for answering questions, whether through MSN (jamespraveen@aol.com), email (james@magclan.cwhnetworks.com) or through the message board attached to this article.
If you have a problem with any of my samples / my topics in general, please feel free to ask me.

## History

• 26/05/06: Posted on CodeProject

## Share

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I live in England, UK in a small town which only just got broadband...

In my spare time, I run a small website design, hosting and maintenance business at www.jamesgupta.com

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 no source code gokceng13-Jun-09 17:31 gokceng 13-Jun-09 17:31
 Re: no source code DevelopmentNoob14-Jul-09 17:15 DevelopmentNoob 14-Jul-09 17:15
 some ideas Georgi Petrov27-Jun-06 2:21 Georgi Petrov 27-Jun-06 2:21
 Suggestion Dustin Metzgar26-May-06 9:44 Dustin Metzgar 26-May-06 9:44
 Re: Suggestion James Gupta26-May-06 10:11 James Gupta 26-May-06 10:11
 Re: Suggestion Dustin Metzgar20-Oct-06 7:07 Dustin Metzgar 20-Oct-06 7:07
 Interesting [modified] Rory Plaire26-May-06 8:04 Rory Plaire 26-May-06 8:04
 Re: Interesting [modified] James Gupta26-May-06 9:04 James Gupta 26-May-06 9:04
 Re: Interesting [modified] Rory Plaire26-May-06 10:00 Rory Plaire 26-May-06 10:00
 Re: Interesting [modified] James Gupta26-May-06 10:10 James Gupta 26-May-06 10:10
 "so that when I'm rich and famous you can sell them for \$100 each"That is *clearly* a joke, to add humour, I like humour, so if I want it in my article I will put it there, and most people would agree its a joke, and that it serves its one and only purpose, to add humour to the article. What am I in this for? Maybe its because I want to make a name, or maybe its because documenting my work serves as proof to myself that i've done something with my time, maybe its because doing these tutorials actually helps me to understand what I'm doing better as I can go over it in my head. The last sentence of your post is a load of rubbish. No-one else here seems to have been quick to judge, some people have given constructive criticism such as "X link is broken", "could you please explain X feature in more detail" etc. Skill? I'll be honest I consider myself beginner - intermediate at DirectX. But I consider that an advantage when writing these articles, as mentioned before I write them mainly to get my head round it, making sure there is nothing I don't understand. As a result, I can focus on points which other people more experienced would leave out because they could solve it in an instant. Citing Sources...Does that mean that I have to cite that I learnt how to initialise a device from MSDN, intellisense, auto complete or wherever I learnt it from?NoIf i had copied and pasted the code, I would add it in a bibliography, but I havent. That heightmap / data extraction, yes I learnt how to use file IO from Riemer's tutorials about a year ago, but since then I have changed it, adapted it etc. You are being un-necessarily critical, and *that* is what really gives a bad impression. just-code-it.netManaged DirectX & C# Tutorials
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Article Copyright 2006 by James Gupta