Project 3 Computer Graphics

Compilation

This project has only been tested on MacOS. It is not guaranteed to work on other platforms.

• Install googletest (brew install googletest on MacOS)
• Install boost
• Go to project root directory mkdir build
• cd build
• cmake ..
• make

Running

./project3 {input_file}

Features 3B

• Everything in 3A

Transmissive

Below is a modified version of outdoor.txt, which swaps the materials for each sphere. The sphere on the left is reflective and the sphere on the right is transmissive with an ior of 1.5

The same image with a 1.1 transmission on the right sphere is

with a 1.01 transmission

and finally with 1.00 transmission

Reflections

Here is the outdoor.txt file with only reflections and no transmissive term

Here is sphere2.txt unmodified for reference

Recursion to a bounded depth

Here is spheres 2 with recursion to a bounded depth of 2 (which was the default)

The same with a bounded depth of 1 is

We can see that the red sphere on the right of the yellow sphere is more illuminated with a bounded depth of 2 than 1.

and with a bounded depth of 0 is

There are no reflections as the depth is limited so no can occur.

Triangles

Here is outdoor.txt with only one triangle

Planes

Here is outdoor.txt but with a triangle replaced with a plane

Here it outdoor.txt but with one vertex in the plane shifted up a bit.

Boxes

A modified version of outdoor.txt with a box

Features 3A

Sample Scene 1

We start with 50 samples per pixel on the file spheres1.txt

Scene Setup

Camera Placement

The viewpoint is adjusted slightly

camera_pos: -6 3 -2

Film Resolution (and Aspect Ratio)

Background Colors

PNG Output

• This should be clear

Primitive

Spheres

• This should be clear

Lighting

Ambient Lights

• This should be apparent by the default image

Point light sources

• This should be apparent by the default image

Multiple light sources

Shadows

• This should be apparent by the default image

Sampling

• I added a custom command samples: {#} to determine the number of samples
• The first sample is always at the center of the pixels
• The rest are randomly distributed between the pixel boundary
• This makes 1 sample equivalent to basic sampling and n > 1 samples equivalent to jittered sampling

Basic Sampling

• results in jagged edges

Sampling with n=100

• smoother result like box-filtering.

Materials

Color & Specularity

• This should be apparent by the default image

Implementation

The code is implemented in C++. Some interesting features

General

• I really like immutable data, so I made a macro #define let const auto
• There are no switch statements for strings in C++. This is an issue for parsing commands. To get around this I made an unordered map of string to enum and then used the switch statement on the enum.
• I use modern C++ 17 features such as destructuring and default nested struct values

Ray Tracing

• Most of the logic occurs in Scene class
• Collision uses the quadratic formula
• Collision which occurs with a t-value less than 0.001 is ignored (to prevent shadow acne)
• For each sample loops over all lights and sees if can reach it (to do this needs to iterate over all spheres)
• Shades with appropriate formulas

Sampling

• See the Features/Sampling section

Challenges

• The switch statements described in the previous

Issues

• So far, I do not see any issues in my code (apart from missing features)
• If there is an issue, feel free to create a GitHub issue.