A naive glsl implementation of a pathtracer written for shadertoy
Here is the shadertoy link.
This is my first attempt at a naive pathtracer. This shader uses Global Illumination techniques and equations to mimic realistics light behaviour in a given 3d scene.
If you would like to learn more about light rendering and pathtracers I cannot recommend enough the TU Wien course available for free on Youtube: https://www.youtube.com/watch?v=pjc1QAI6zS0&list=PLujxSBD-JXgnGmsn7gEyN28P1DnRZG7qi&ab_channel=TwoMinutePapers This is a big shout-out to TU Wien University and professors Károly Zsolnai and Thomas Auzinger for making this wonderful course available to everyone on the internet.
This program is heavily based on the basic cpu pathtracer named SmallPaint presented in the course and improves on it with a much faster convergence using gpu parallelization instead of simple cpu multithreading. To learn more you can find its source code here
This is a multipass shader that stores for each pixel the sum of all the previous ray colors that were shot from the pixel. In the alpha channel we store the total number of samples that were shot so that we can calculate the average of all the rays color by the number of rays. We do this in the other shader that is the entry point of the application.
Feel free to reuse any part of the code that you see. Enjoy!
Here are some images generated in shadertoy (2 minutes/images @ 120 fps):
