Description:

This assignment adds direct lighting and glossiness to the path tracer. Direct lighting involves explicitly adding the light contributed from all lights in a scene when calculating the color of an object at a point on the object. This results in a smoother, less grainy image since we do not rely on random rays probablistically hitting the light. Instead, we send "shadow rays" directly from the object to a random point on each light in the scene.

Glossiness simply involves adding some percentage of the diffuse and reflective (mirror) color components when calculating global lighting.

This image includes both direct and global illumination. This image was generated using 512 samples per pixel with dimesions of 512x512 pixels. The emissiveness of the light is 4.0. There is a glass sphere in the upper left-hand corner, a mirror sphere to the right, and a green glossy sphere in the center. The floor is glossy as well. The walls and ceiling are diffuse.

This image includes only global illumination. Notice that the image is more grainy than the above image, which uses direct light as well as global illumination. This image was generated using 512 samples per pixel with dimesions of 512x512 pixels. The emissiveness of the light is 5.0. There is a glass sphere in the upper left-hand corner, a mirror sphere to the right, and a green glossy sphere in the center. The floor is glossy as well. The walls and ceiling are diffuse.

This image includes only direct light. The lighting appears very smooth, but there is no inter-reflection in the scene. This image was generated using 512 samples per pixel with dimesions of 512x512 pixels. The emissiveness of the light is 5.0. There is a glass sphere in the upper left-hand corner, a mirror sphere to the right, and a green glossy sphere in the center. The floor is glossy as well. The walls and ceiling are diffuse.

One problem with the algorithm I used is that I don't count light that goes through the glass object when calculating direct light. This ends up being visually acceptable since light that travels through the glass object does get added in when I include global illumination.