Course: Instructor:
Project 5: Date due:
“Computer Graphics”, ECS 175, Fall Quarter 2016 Bernd Hamann
“A SIMPLE RAY TRACER”
Friday, December 2, 2016
The fifth project requires the implementation of the ray tracing algorithm discussed in class. Write a program to render a scene in 3D space containing planes and other implicitly defined surfaces of degree 2 (e.g., spheres and ellipsoids), and triangulated surfaces. The input parameters for the program are the from point, the at point, the up vector, and the viewing angle α. The position of the light source(s) and the resolution of the final image (N × N pixels) will be specified by the user as well.
You must implement the generalized Phong illumination model considering direct and global illumination effects, given by the formula
I = Idirect + Iglobal
= kaIa + Ilight kd(⃗l·⃗n)+ks(⃗r·⃗v)n+krIr +ktIt,
where the Phong illumination formula now incorporates the global illumination term Iglobal. The values Ir and It are vector-valued (red, green, and blue components). They are obtained by applying the Phong illumination model recursively. All parameters in this equation are input for the ray tracer. The user can specify the color properties of each object in the scene. The global illumination term must be computed recursively as discussed in class. When computing the color/intensity for a particular pixel, stop the recursion when a user-specified maximum number of recursion levels is reached or when a reflected/refracted ray hits one of the faces of the bounding box surrounding the given scene.
For this project, you need to consider intersections between rays (=lines defined in parametric form) and implicit surfaces and between rays and triangles approximating surfaces. Use the intersection algorithms discussed in class. In order to allow transparent objects, you also need to implement the procedure for computing refracted rays. This requires the specification of refraction coefficients η for all objects/media in the scene. The user must be able to change these. Shadow feelers must be used at each point encountered in the scene to determine whether it receives direct light from a light source or not. To satisfy the expectations for this project, when a point lies “in shadow” you do not need to consider the concept of direct transmission of light from a light source through a transparent medium that exists between the point and the light source.
The scene you render must contain at least five different surfaces (e.g., plane, sphere, ellipsoid).
K + distance(f , p)
1
Besides having to hand in a program listing, please prepare a “manual sheet” explain- ing how to use your program.
The overall grade (on a scale from 0 to 100) will depend on i) completeness (40%), ii) correctness (40%), iii) interface quality (15%), and iv) the manual sheet (5%). No project will be accepted when it is more than seven (7) days late; for each day, one (1) point will be deduced.
HAVE FUN !!!
2