Polarizing Filters in Real-Time Ray Tracing With DXR

This repository hosts the source code for my master's thesis titled Real-Time Ray Tracing With Polarization Parameters.

Three renderers are implemented in the application:

• Baseline uses conventional shading methods without polarization parameters.
• Polarization uses polarization parameters in all rays.
• Hybrid uses the Polarization version's methods/payloads for all primary rays, and the Baseline version's methods/payloads for all reflection rays.

All three renderers use Whitted-style ray tracing with reflection rays (but no shadow or refraction rays). The shader code for the three renderers can be found in Baseline.rt.hlsl, Polarized.rt.hlsl, and Hybrid.rt.hlsl respectively. A demo project called PolarizationDemo is also included to compare the graphical difference between the different renderers.

For more information about the underlying theory and the implementation, see the included thesis [pdf].

Polarizing filter demonstration

Unfiltered output

Polarization renderer	Hybrid renderer
Vertically angled filter	Vertically angled filter
Horizontally angled filter	Horizontally angled filter
Degree of Polarization	Degree of Polarization

Demo Settings

• Recursion depth The maximum number of recursive reflection rays per pixel (e.g., with a recursion depth of 2 there will be one primary ray and up to two reflection rays per pixel).
• Versions
  • Basline
    • Polarized
  • Polarization
    • Polarized
    • Hybrid
  • Hybrid
    • Polarized
    • Hybrid
• Miss color The color of the sky and any ray that doesn't hit any scene geometry.
• Uniform light Disables all the light sources in the scene and uniformly lights the scene with diffuse light.
• Attach light Attaches a point light to the camera (only works if the first light in the scene is a point light).
• Polarizing filter
  • Angle The rotation angle of the linear polarizing filter in degrees, with 0 repressenting a horizontally angled filter.
• Polarization Output
  • DOP Degree of Polarization.
  • Plane The angle of linear polarization.
  • TOP Type of Polarization (blue is linear, yellow is elliptical).
  • Chirality Handedness of elliptical polarization (blue is left handed, yellow is right-handed).
  • Sanity Should result in a black screen unless there are impossible Stokes vectors in the output image.
  • Normal Surface normals in the scene.
• Materials Pre-defined metals can be selected from a list. Their complex index of refraction values can also be set manually.

Requirements and Installation

Nvidia's Falcor Rendering Framework was used as the base of this project, so the same restrictions and requirements apply. Follow the installation guide for Falcor 3.2.2 if you want to build this project.

Test Scenes

Test scenes can be downloaded from the Open Research Content Archive (ORCA). You might have to edit some path names in the code to get them to load correctly.

Scenes can also be created/modified with the included SceneEditor project.

Versions

• v1.01 Cleaned up version with a minor (non-performance impacting) bug fix.
• v1.00 Version used to run the performance tests in the thesis

Citation

Thesis

@mastersthesis{Enfeldt20thesis,  
   author  = {Enfeldt, Viktor},  
   title   = {Real-Time Ray Tracing With Polarization Parameters},
   school  = {{Blekinge Institute of Technology}},
   address = {Karlskrona, Sweden},
   year    = {2020},  
   month   = {06}
}

Application

@Misc{Enfeldt20application,  
   author = {Enfeldt, Viktor},  
   title  = {Polarizing Filters in Real-Time Ray Tracing With {DXR}},  
   year   = {2020},  
   month  = {06},  
   url    = {https://github.com/viktor4006094/DegreeProject},  
   note   = {Version: 1.01}  
}

If you cite the application then remember to also cite the Falcor Rendering Framework.