Diamond Square terrain generator

This plugin is tested to work on 3ds Max 2014. The project files use Visual Studio 2012, but the compiler is set to the VS 2010 compiler. The project will not compile with the 2012 compiler; 3ds Max 2014 plugins must be compiled with the 2010 compiler. My build environment was Windows 8.1; you may have to tinker to get compilation to work otherwise.

Most of the interesting things are in Grid.cpp, which generates terrain using the diamond-square algorithm over a grid.

The plugin will generate UV coordinates covering the grid; if you want a different mapping, apply the UVW Mapping modifier on top of this object.

A quick and dirty explanation of this implementation:

• It wraps, i.e. it considers the left edge of the grid a continuation of the right edge and the top edge a continuation of the bottom.
• It is iterative; it starts by setting the radius to half of the size of the grid. This segments the grid into one square.

+ - - - +
|       |
|       | One square.
|       |
+ - - - +

• The height of the center of the square is calculated as avg(corners) + random(d) where d is a height scaling factor.

@ - - - @
|       |
|   *   | Center point (*) calculated from avg of corners (@).
|       |
@ - - - @

• The heights of the center-top and center-left point of the square are calculated in the diamond step, using points in the four cardinal directions.

@ - * - @
|       | Top-center point (*) calculated by looking to the left, right, top, and
|   @   | bottom (@). Note that looking up from the top-center point actually
|       | wraps around to the bottom-most point.
+ - @ - +

• At the end of the iteration, d is scaled down in proportion to a roughness factor. There should now be four new squares from the original one square.

+ - + - +
| 1 | 2 +
+ - + - + Four new squares.
| 3 | 4 |
+ - + - +

License

The MIT License (MIT)

Copyright (c) Steven Dao 2014

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.