Description
Ray Tracing II
Overview
In this project, you will add additional features to your ray tracer from Assignment 7, such as
more complicated materials, environment lights, or depth of field effects.
NOTE: For this project, you will choose ONE out of Part 1 or Part 2 to complete. In other
words, you can choose any combination of THREE parts like the combination (xx, Part 3, Part 4).
However, if you’d like to complete all four parts, please do so! This project is one of the most
rewarding to complete fully, as you’ll be able to render almost anything at the end: all sorts of
fancy materials in different environments, with any camera angle and focus depth.
• Mirror and Glass Materials (20 points)
• Microfacet Material (20 points)
• Environment Light (30 points)
• Depth of Field (30 points)
You will also need to read these articles:
• Experiments, Report and Deliverables
In particular, please read the Experiments, Report, and Deliverables page before beginning the
project. There are many deliverables for this project, so please plan accordingly. Several parts of
this assignment ask you to compare various methods/implementations, and we don’t want you to
be caught off guard!
Getting Started
Please consult the Assignment 6 spec for details on the user interface. Here are some old and
new command line flags you’ll want to pay attention to:
• -e some_map.exr loads an environment light .exr image file (part 3)
• -b 1.23 sets the lens radius to 1.23 (part 4)
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• -d 4.56 sets the focal distance to 4.56 (part 4)
Please consider using the CGL Vectors Library to write all your math computations to simplify
your code and ensure correctness.
A new mouse interaction: In render mode, after thin lens has been implemented, you can
right click on a part of the image and automatically set the appropriate focal distance (autofocus).
This is already done for people using pre-built binaries. For people using their own Assignment 6
code, you need to add this function to your pathtracer.cpp:
1 void PathTracer:: auto focus (Vector2D l o c ) {
2 Ray r = camera- >generate \_ray( l o c .x / sampleBuffer.w, …
3 l o c .y / sampleBuffer.h);
4 In t e r s e c t i on i s e c t ;
5 bvh- > i n t e r s e c t (r , \& i s e c t );
6 camera- > fo ca lD istan c e = i s e c t . t ;
7 }
As well as two new keyboard commands:
• k | l : Increase/Decrease the camera lens radius
• ; |
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: Increase/Decrease the focal distance
Also please use the “cell render” mode to debug, where you can interactively click and drag to
select a small region of the screen to be rendered. Press c (after pressing r ) to toggle this mode
in the GUI.
Integrating Previous Code
For Assignment 7, you will need a working implentation of Assignment 6. You have the option
of either porting your code from Assignment 6, or using pre-compiled binaries generated from the
staff solution.
Using the Staff Library (Default settings, Recommended)
The project has been configured to default to this settings. If you just cloned the repository,
you can directly start building & writing code. You can also use this to check / compare your own
Assignment 6 solution.
To use the provided library, set the build option BUILD_CUSTOM to OFF (Default) in
CMakeLists.txt. This will tell the generated makefiles to ignore your Assignment 6 code, and
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include the library that matches your system instead. Note that the staff binary will generate a
watermark on the corner of your image.
Using Your Own Code
To use your own code, set the build option BUILD_CUSTOM to ON in CMakeLists.txt. Then,
you’ll need to copy over the following files from your previous assignment, and place them in your
src/ directory.
• src/scene/sphere.cpp
• src/scene/triangle.cpp
• src/scene/light.cpp
• src/scene/bvh.cpp
• src/scene/bbox.cpp
• src/pathtracer/camera.cpp
• src/pathtracer/bsdf.cpp
• src/pathtracer/pathtracer.cpp
Additionally, you will need to delete all the functions under Assignment 7 code in your bsdf.cpp.
This includes functions:
• Vector3D MirrorBSDF::f(const Vector3D &wo, const Vector3D &wi)
• Vector3D MirrorBSDF::sample_f(const Vector3D &wo, Vector3D *wi, float *pdf)
• Vector3D GlossyBSDF::f(const Vector3D &wo, const Vector3D &wi)
• Vector3D GlossyBSDF::sample_f(const Vector3D &wo, Vector3D *wi, float *pdf)
• Vector3D RefractionBSDF::f(const Vector3D &wo, const Vector3D &wi)
• Vector3D RefractionBSDF::sample_f(const Vector3D &wo, Vector3D *wi, float *pdf)
• Vector3D GlassBSDF::f(const Vector3D &wo, const Vector3D &wi)
• Vector3D GlassBSDF::sample_f(const Vector3D &wo, Vector3D *wi, float *pdf)
• void BSDF::reflect(const Vector3D &wo, Vector3D *wi)
• bool BSDF::refract(const Vector3D &wo, Vector3D *wi, float ior)
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Details
Do not convert or resize your .png. files. Use either the command line rendering mode or the
S key to save screenshots, not your own OS’s utility (like Assignment 6). Keep your images in a
subdirectory called images/ in the docs/ directory. We recommend using the -r 480 360 command
line flag to set resolution at 480 by 360 for your screenshots.
Please also make sure that your writeup indicates clearly which two (or more!) parts you chose.
Final Note
As mentioned earlier, each of the parts of this project gives you something to work with, and
if you finish all of Assignment 7, you can basically render anything. When you’re done, feel free
to show it off! Make some fancy scenes and materials, or play with the lens! Again, be creative
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