This is a small program that does 2D ray casting with 2D boxes.

All the controls are on the left side, and this is what they do from top to bottom.

Move (Button): Click this button, then click and drag a box to move it around
Set Light (Button): Click this button, then click anywhere on screen to set the light location
Add (Button): Click this button then click and drag then release to create a box on screen
Remove (Button): Click this button, then click a box to remove it
Show Light (Checkbox): Check to toggle light
Light Size (Value Slider): Slide to change size of light circle
Darkness (Value Slider): Slide to change opacity of darkness
Ray Count (Value Slider): Slide to change the number of rays used during method 1 raytracing
Use Method 1 (Checkbox): Check to switch to method 1 raytracing
Use Method 2 (Checkbox): Check to switch to method 2 raytracing

Light Method 1
Method 1 is slower than method 2, but produces a more accurate light circle.

Light Method 2
Method 2 is faster than method 1, but the light circle is not a smooth curve.

OpenGL 3.0 or greater is required to run.

Windows
To compile on windows, run the project with Visual Studio 2019 or greater and build it.

Linux
To compile (starting in the root project directory)

cd src
make

To run (starting in the root project directory)

cd src/build/
./2DLight

If you get errors while building or running on linux, check the error section below.

SDL
http://www.libsdl.org/
Used for

• GUI's
• Threads
• Timing

GLEW
http://glew.sourceforge.net/
Used to access newer OpenGL functions

GLM
http://glm.g-truc.net/0.9.5/index.html
Used for matrix math

SOIL
http://www.lonesock.net/soil.html
Used to load texture files

Go to the link above. Go to downloads. Download the new development library. At the time of writing it is "SDL2-devel-2.0.10-VC.zip (Visual C++ 32/64-bit)". Replace the files under src\include\SDL and the lib files in src\lib. Use the x86 libs and not the 64 ones.

Error: OpenGL headers cannot be found
If you are getting OpenGL errors, run the following commands

sudo apt-get update  
sudo apt-get install libglu1-mesa-dev freeglut3-dev mesa-common-dev  

Error: ./2DLight: error while loading shared libraries: libSDL2-2.0.so.0: cannot open shared object file: No such file or directory

Open the file

/etc/ld.so.conf  

Add the following line the the bottom

include /usr/local/lib

Then run the following command

sudo /sbin/ldconfig

SDL2, GLEW, and SOIL are required to compile. If you do not have any of these libraries, follow the instructions below to install them.

SDL 2
Download SDL2-2.0.3.tar.gz from here http://www.libsdl.org/download-2.0.php
Then run the following commands

tar -zxvf SDL2-2.0.3.tar.gz
cd SDL-1.2.7
./configure
make
sudo make install

GLEW
Download glew-1.10.0.tgz from here http://glew.sourceforge.net/
Then run the following commands

tar -zxvf glew-1.10.0.tgz
cd glew-1.10.0
make
sudo make install

If you get errors about -lXmu and -lXi not being found when trying to install this package, then do the following.

sudo apt-get install libxmu-dev
sudo apt-get install libxi-dev

SOIL
Download soil.zip from here http://www.lonesock.net/soil.html
Then run the following commands

unzip soil.zip
cd Simple\ OpenGL\ Image\ Library/projects/makefile/
mkdir obj
make 
sudo make install