For assignment 5 Brandon and I decided to extend our ray tracer from assignment 4. We made the following major enhancements to our project:

• Acceleration Structure
  We implemented a bounding box hierarchy as described in our textbook to hold all of the objects in a scene. This dramatically increased rendering speeds, especially on sparse parts of the scene.
• Refraction
  As you will see in the images above, we have refraction implemented for sphere and triangle primitives. This lets us render balls and cubes of glass. The sphere command in an input file now takes another parameter to define its refractive index. There is a "trirefractive" command that takes in triangle coordinates as well as the refractive index of the substance on the side of the triangle opposite the normal.
• Depth of Field
  We can now simulate a viewers depth of field. The further an object is away from the camera's "look at" parameter the more blurry it is. A square lens is simulated and configured with the "lenssize" command followed by a floating point number.
• Area Lights
  Area lights are now possible in our ray tracer. This produces beautiful effects like soft shadows. An area light is defined in an input file with the command "area" followed by a position, width, length, up-axis (0, 1, or 2), and a color.

Now for the pictures.

This rendering was inspired by one of the images on Wikipedia's page on ray tracing. You may notice the area light reflected in each sphere. This area light is the reason for the soft shadows on the ground. The white ball in the center is perfectly in focus and as you get further away from it things are increasingly blurry thanks to our depth of field implementation. This scene was rendered with 1024 samples, and took about an hour to complete. It would have taken much longer without our acceleration structure in place.
Here is the same image, but the sphere in the center is now refractive.

See below for annotations that describe everything that is going on in this complex image of refractive spheres.

This one is just awesome.

This is a picture of a refractive cube and sphere.

This is the scene3.test input file given to us with some modifications. The camera is more focused on the good parts of the scene and now there are two area lights causing overlapping shadows.