initilized from: http://graphics.ethz.ch/teaching/former/imagesynthesis_06/miniprojects/p3/index.html


# Case 1: 256x256 image, background, but no fire
./fire32-demo -l f32pk.dat -W 256 -H 256 -d 10 -F off -b office.png


# Case 2: add rigid object. 
#***Important: by not drawing the fire, the drawing is orders of magnitude faster.
might need to lower the speed! But, it will be slow if saving images. ***
./fire32-demo -l f32pk.dat -W 256 -H 256 -d 10 -F off -b office.png -r sky.png -R 0.01


# Case 3: rigid object in a line (sinusoid), scaled by the "L"
./fire32-demo -l f32pk.dat -W 256 -H 256 -d 10 -F off -b office.png -r sky.png -R 0.01 -M line -L 3


# Case 4: fire plus rigid in a line, together 
./fire32-demo -l f32pk.dat -W 256 -H 256 -d 10 -b office.png -r sky.png -R 0.5 -M line -L 3


# Case 5: same as 4 but now save images to diretory (Z flag) 
./fire32-demo -l f32pk.dat -W 256 -H 256 -d 10 -b office.png -r sky.png -R 0.5 -M line -L 3 -s 1 -Z  ./tmp