Procedural Terrain Generation

Joseph Dombrowski - Terrain Logic
Rohit Nirmal - Rendering

Intro:
This was our final project in our graduate Computer Graphics class for Fall 2011 at the University of Houston.

Compiling:
This code uses the SDL development libraries, and requires SDL.dll to run on Windows. Get both at libsdl.org.
You also need the OpenGL and GLU libraries, but most computers with graphics drivers should have these.
The makefiles assume g++ is installed, but the program has been tested with Visual Studio 2010, and should
compile as long as the paths to the libary are consistent with the #includes.

Run the makefile for your specific platform once you have the required dependencies.

Usage:

Open the settings.ini file to set your resolution and whether you want the program to run in fullscreen mode.
Change the terrainDim for different size terrain. Higher numbers result in higher detail terrain at the cost
of greater time to generate the terrain and rendering performance. Change the minRegions and maxRegions to 
change the variance of the terrain. Finally, change terrainType to one of the names of the text files supplied,
such as General, Highlands, Lowlands, Water, etc.

Run the executable to generate the terrain. Depending on your computer and the size of the terrain being generated,
this can take a while. For quick and decent results, I recommend a terrainDim of 512.

Running the executable in the command-line will show progress bars on generating the terrain.

Controls:

W - Move forward
S - Move Back
A - Move Left
D - Move Right
Space - Move Up

Mouse - Look around

Shift - Hold to move faster

X - wireframe

1 - View default terrain coloring. On by default.
2 - View region based terrain coloring.
3 - View height based terrain coloring.
4 - View "enabled" points after subdividing terrain as a quadtree.
5 - View simplified terrain after subdividing terrain as a quadtree.

R - Generate another terrain. There's no loading bar except in the console.

N - Show terrain generation as a series of steps.

Escape - Quit the program.

Simplification:

The program includes a quadtree simplification method that I copied from here:
https://www.gamedeveloper.com/programming/continuous-lod-terrain-meshing-using-adaptive-quadtrees

Read that if you want more information on how it works. If you want to tweak how many
triangles should be removed, change the "error" global variable at the top. Higher
values mean the terrain is simplified even more. Make it too high and you'll end up with
a flat square terrain.

Because my simplification method relies on the terrain being represented as a quadtree,
terrainDim MUST be a power of two plus one, such as 129, 257, 513, 1025, etc.

Issues:
-Simplification causes cracks to form between high and low resolution terrain.
I have the method removeCracks() to fix it, but it doesn't completely do the job.
-Compiles, but doesn't really work on Ubuntu, the only Linux distribution I tested.
		-SDL_WarpMouse makes the camera impossible to use, even though I have the
		checkForCentered variable that's supposed to fix this. An quick solution is to
		comment out SDL_WarpMouse, but it will be easy for the user to lose focus in windowed
		mode.
		-glColor doesn't seem to work when GL_LIGHT is enabled, but does in Windows.
		-The settings file for the chosen terrain type will sometimes not be found, causing a crash.
-Compiling with g++ will sometimes cause some corners of the terrain to have crazy high
or low heights, but compiling with Visual Studio causes no such issue.

To Do:
-Water rendering.
-Textures.
-Saving terrains.