University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 3
Nuofan Xu, Windows 10, AMD Ryzen 3800X, RTX2080 Super
A CUDA-accelerated path tracer: a global-illumination renderer.
(The walls are implemented as diffusing surface, and the ball is implemented as perfect specular surface.) **
-Basic pathtracer -Refractive, Reflective, and Diffused surfaces -Depth of Field -Direct Lighting
The pathtracer supports the following material surfaces:
- diffuse: light scatters uniformly from the surface
- specular/reflective (perfect): light reflects perfectly off the surface.
- refractive (using Schlick's Approximation of the Fresnel effect to blend reflective and refractive light bounces).
(The ball is implemented with 1.5 refraction rate)
To get a direct lighting effect in our images we want to make the last bounce of each ray hit a light source. We do this by randomly selecting a point on a randomly selected light and setting the direction of the ray to that point. The first image is without direct lighting, and the second one we can see is overall brighter with the direct lighting enabled.
Depth of field simulates a physical aperture by varying the origin and direction of rays shot from the camera. DOF is defined with a focal distance from the camera, at which objects are perfectly in focus, and an aperture radius, defining the amount of variance added to each ray.
(no DOF; DOF with distance 5.5, aperture 0.4; around 1000 iterations each)
Camera rays are shot from the camera's position in the direction of a pixel. Antialiasing jitters the target of the ray within a pixel. This is a brief computation that happens once per pixel per iteration; it has little impact on performance.
(Enlargement of antialiasing along wall corners (right) vs no antialiasing (left))
This pathtracer uses thrust::stable_partition to perform stream compaction on dead
rays. Reference: https://pbr-book.org/
To build: make
To run: build/cis565_path_tracer SCENE_FILE.txt.
Some sample scene files are found in scenes/.
Any feedback regarding the correctness of code or the pathtracer in general is welcome.