CRaytrace 🔭

Implementation of a Monte-Carlo raytracer in C++. This project was done for the course TNCG15 at LiU, ITN during the fall of 2020.

Issues:

• [Should be resolved] RGB values might not be normalized to [0, 255] in some cases
• Möller-Trumbore check might fail sometimes due to doubleing point errors
• Area light source appears gray-ish when it should be white
• Cosine term from rendering equation as lightAmount cause shadow-acne for some reason

TODO:

• Ignore rays that end on light sources, use penultimate ray as final ray.
• Figure out why rays seem to get trapped inside of boxes and tetrahedra.
• Refactor code base
  • Separate code into more files
  • Collect forward-declarations in one header file, which is included first
  • Replace Color with glm::dvec3
  • Use either snake_case or camelCase for variables/methods (PascalCase for classes)
  • Color convenience methods and constants
• Oren Nayar surfaces
• Transparent surfaces
• Set const rendering parameters
  • Lightning sample amount
  • Importance reduction
  • Russian roulette cutoff

DONE:

• Walls
• Möller-Trumbore algorithm for triangle intersections
• Set up CMake for building the project
• Handle dependencies with CMake
  • Set up GLM library as dependency
  • Set up PNG++ library as dependency
• Implement (simple) rendering loop
  • Iterate over all pixels
  • Send rays through each pixel and set the color of the pixel to the color of the first intersected triangle
• Move class/struct definitions into header files
• Create implementation file for class memeber functions
• Make triangle verticies public/add getter functions
• Get XYZ components from a glm::DVec4
• Changed dvec to vec
• Camera should have separate render and create_image functions
  • Render: Cast all the rays and calculate the doubleing point color values of each pixel
  • Create image: Convert the doubleing point RGB values to png::byte
• Save render results to an image
  • Convert from double-valued colors to 8 bit unsigned integer values
  • Find a way to push pixel values into some kind of an image format in C++
• Simple local lighting model
  • Implement lights in the scene
  • Check that the triangle normals make sense
• Implement scene objects
  • Tetrahedron
  • Sphere (implicitly with radius) MOA
  • Handle mutliple ray intersections, using the nearest intersection
• Shadow rays on "local light check"
  • Is there an intersection for the ray going from the object to the light source?
• Handle "ray trees"
  • Spawn more rays when intersecting something reflective/refractive
  • Calculate intensity values for the ray by working from the ends to the original ray

How to terminal (Guide for Dummies cough Moa)

• Go up one directory: cd ..
• List the items in a directory: ls
• List all the items: la
• Make a new directory: mkdir [name] (e.g. mkdir build)

Building and running

From the root directory of the project (e.g. craytrace)

1. cd build
2. cmake .. (sometimes you need to rm -rf build/* from craytrace first to restore build)
3. cmake --build .
4. ./CRaytracer (or whatever the binary is called. tip: tab is your friend)

Developed by:

• Frans Johansson
• Moa Gutenwik