← Home
This assignment has two parts -- part (a) and part (b) -- due at different times.Part (a): Basic Raytracer
Due: Sun Sep 4, 23:59:59 IST
Assignment Description
You will write a raytracer in this assignment. This is also your proverbial trial by fire, your initiation rights, your first claim as a graphics professional -- raytracers are the bread and butter of high quality rendering. Good luck!
IMPORTANT: To complete this project, you need to read the PDF instructions. Without it this assignment will be extremely hard! Please save yourself and us the trouble and read it fully. Also refer to the background reading if necessary.
Instructions
Find the instructions for this assignment in PDF here.
You need to complete all the functions whose body contains IMPLEMENT_ME. Note that while these functions will trigger errors if you call them without replacing them with your own code, not all of them are called by the default skeleton code. This means you may miss some parts that you have to work on. Hence, please search for all instances of IMPLEMENT_ME and make sure you've addressed each one (except the ones in the Triangle class, those are for 3(b))!
Skeleton Code
Results
We require you to correctly render scene{1..5}.scd. Note that there're more .scd files than we require you to render. Those are for A3(b), to be posted later below. Here are the 5 raytraced images you will be generating (for trace depth 2):
| Scene 1: (3 primitives) |  |
| Scene 2: (3 primitives) |  |
| Scene 3: (1000 primitives, takes time to render) |  |
| Scene 4: (5 primitives) |  |
| Scene 5: (47 primitives) |  |
Here is a breakdown of the different lighting effects inside Scene 1:
| Ambient Component Only |  |
| Lambertian Component Only |  |
| Specular Component Only |  |
| Ambient and Specular |  |
Submission Instructions
You need to submit just your source code. Do a "make clean", zip your src folder, and upload it on Moodle. Do not upload anything else, not even a Readme. Do not change any of the function signatures in the skeleton code (we will test them automatically), though you can add new functions/classes as needed.
Part (b): Advanced Raytracing
Due: Sun Oct 2, 23:59:59 IST
Assignment Description
This part of the assignment is open-ended. You need to add THREE POINTS worth of non-trivial advanced features to your raytracer from part (a). You're free to choose what you want to implement, but if it's not on the list below, check with me in advance to figure out how many points it counts for. Here are some suggestions. For some of these, you may need to write your own .scd files, extend the .scd format, or specify the input in some other clean way (avoid hardcoding it in the code if possible). You may make any changes to the code you need.
- (1 point) Refraction: Handle transparent objects. As a test, try viewing an object through a glass sphere, or even better, try to model a lens-shaped object. The latter will count for an extra point or two since you have to write a new primitive type, see below.
- (1 point) Area lights: Sample lots of points over the area and trace multiple shadow rays to them. The result should have nice soft shadows. Also figure out how to handle Phong shading in this situation.
- (1 point) Triangles: Complete the Triangle class (in Primitives.[ch]pp), and use it to render the "teapot" and "dunkit" scenes which involve triangle meshes. The code to load the mesh and populate the World object with its triangles is already present in the skeleton code. You can use MeshLab to preview the meshes.
- (1 point each) Other primitives: Implement quadrics, torii, superquadrics etc. See Sid's guide for solving equations of degree 3 and 4.
- (2 points) Constructive solid geometry (CSG): CSG models new objects by boolean operations on old ones. For instance, a convex lens is the intersection of two spheres. Raytracing provides a very clean way to handle CSG: just check which intersection points satisfy the condition.
- (2 points) Acceleration structure: Implement an acceleration structure, such as a bounding box (or bounding sphere) hierarchy, or an octree, or a kd-tree, and use it to speed up rendering of scenes like #3. Your structure should work for (at least) spheres and triangles, and be general enough to work on any scene with these primitives. Suggestion: add a function to the Primitive class to get the bounding box of the primitive, and specialize it in derived classes. When constructing the tree, use this bounding box (instead of the actual primitive, which can be trickier) to determine membership in a node.
- (2 points) Camera lens with depth-of-field effect: See midsem question 6. Instead of a pinhole camera model, simulate an actual lens placed in front of the camera, with associated background blur effects. Remember, the eye position is no longer important -- you need to cover the surface of the lens with lots of rays from each pixel on the image plane, and track them after refraction through the lens. If you have to implement a new primitive for this, the associated points add up. But you can also just hand-code the specific refraction formula for this special case (thin lens approximations are fine).
- (2 points) Arbitrary BRDFs
- (3 points) Global illumination: via photon mapping, or radiosity.
Grading Scheme
33.3% for every implemented point, clamped to a maximum of 150%.
Submission Instructions
Please submit a zip of your assignment directory, containing:
- All source code, which should build on our Unix systems by just typing make without our having to install anything extra.
- All .scd, .obj and any other data files in the data subfolder.
- An images subfolder, at the same level as data, containing all your new rendered images.
- A plain-text README file detailing:
- A brief writeup on everything you implemented. One bullet per feature. Include all info you think is relevant, including and especially a list of the functions and classes created/modified to implement the feature.
- The EXACT Bash command lines needed to reproduce every single image in images. We will run the command lines from the data folder. We should not need to rebuild your code to turn different features on/off -- make these command line options. List the full command lines one after another, e.g.
../trace refraction_scene.scd ../images/refraction_image.png 4 ../trace csg_scene1.scd ../images/csg_image1.png 2 ../trace csg_scene2.scd ../images/csg_image2.png 2 ../trace area_light_scene.scd ../images/area_light_scene.png 3 ../trace scene3.scd ../images/complex_scene.png --enable-octree 3
- The approximate time taken to execute each of the command lines above on your system.
Do NOT submit object/executable files. Run make clean before zipping.
Acknowledgements
The inspiration for the structure of this project, and sections of the source code, came from Niels Joubert and James Andrews' framework for Berkeley's CS184 Intro to Graphics course.