ptracey

P.Shirley's The Rest of Your Life Path Tracer with Assimp and Spectral Rendering Switch

Docs are available in: https://d-k-e.github.io/ptracey/

This is basically what you get in P. Shirley's awesome The Rest of Your Life tracer available in here in book form. For the code checkout here.

with model loading capabilities of assimp, which is available in here

It has couple of extra features as well:

• Very simple multi threaded rendering with c++11 <future>.

• Each mesh and model is loaded as bvh_node.

• Documentation (well automatically generated by doxygen for now, but I am hoping improve it when I have more time)

• Spectral Rendering switch.

In Progress

• Metropolis Light Transport algorithm for rendering

• Refactoring...

• Other bsdfs.

Requirements

• Assimp

• c++11+

• cmake 3+

• rapidcsv for reading csv files (included in headers)

• stb for reading images.

Building

Just create a build directory in the project.

• mkdir build

• cd build

• cmake ..

Install

Asset paths are hard coded into code, so stable install location would be good for the overall project. I have used bin folder inside the main directory.

• mkdir bin

• Now you can do stuff like make install and arrange your assets with respect to the install location of your executable which in this case is bin folder situated at the same level of the README file.

Small Note on Spectral Rendering Switch

Spectral rendering code has been heavily influenced from pbrt especially during conversion of rgb's to spectrums. It also inherits the idea of having the capacity to compile code with different rendering switches.

If you want to turn on, spectral rendering you should comment out the relative section in spectrum.hpp. Once you rendered the image, if you are unsatisfied with what you have, try changing xyz2rgb__* function under sampled_spectrum.hpp, with something else defined in specutils.hpp. If you are unsatisfied with all of the functions there, try using another matrix for conversion process.

You'll see that besides the function xyz2rgb_pbr which is the exact same function used by the pbr source code, all functions are defined in the same manner. You define a matrix, then multiply it with xyz vector. If you are interested in doing spectral rendering in c++, you should be able to understand what is going on in the other functions so much so that you reproduce them with different values for matrices.

Another side note. Though the code is heavily influenced from pbrt, the spectral power distribution object defined in spd.hpp, has relatively distinct features. I differ a lot from pbrt in that perspective, for the better or the worse.

Screen shots

Here are some eye candy. They are mostly reproductions from P. Shirley's books.

Spectral Rendering Output

A Special Hallmark for #RTKitty

The model is made by EKA: twitter @bakin___

It is traced by PTracey.

• Anger Kitty

• Glass Kitty

• Invisible Kitty

• Metal Kitty

• Night is Yours Kitty

• Glow me Thy Name Kitty