Readme update + license

Readme.md

@@ -1,3 +1,14 @@
+# Raytracing in 256 lines of bare C++
+
+This repository is a support code for my computer graphics lectures. It is not meant to be the ultimate rendering code or even physically realistic. It is meant to be **simple**. This is a work in progress, I'll populate the project's wiki shortly.
+This project is distributed under the [DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE](https://en.wikipedia.org/wiki/WTFPL) lincense.
+
+If you are looking for a software rasterizer, check my other part of the lectures:  
+https://github.com/ssloy/tinyrenderer/wiki
+
+In my lectures I tend to avoid third party libraries as long as it is reasonable, because it forces to understand what is happening under the hood. So, the raytracing 256 lines of plain C++ give us this result:  
+![](https://raw.githubusercontent.com/ssloy/tinyraytracer/master/out.jpg)
+
 # compilation
 git clone https://github.com/ssloy/tinyraytracer.git  
 cd tinyraytracer  
@@ -6,3 +17,11 @@ cd build
 cmake ..  
 make  
 
+# Homework assignment
+[homework_assignment branch](https://github.com/ssloy/tinyraytracer/tree/homework_assignment) contains all necessary stuff to easily add environment maps:
+![](https://raw.githubusercontent.com/ssloy/tinyraytracer/homework_assignment/out-envmap.jpg)
+
+... and triangulated meshes:
+![](https://raw.githubusercontent.com/ssloy/tinyraytracer/homework_assignment/out-envmap-duck.jpg)
+
+All boring code (image/obj files serializer etc) is already added; to obtain the above image ot suffices to add 10-20 lines of code.