Computer Science 112
The Art & Science of Computer Graphics

Spring 2016, The College of Saint Rose

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For this week's Studio/Lab exercise, you will be working with Bézier curves to construct a model of a stained glass window.

A Stained Glass Window

We saw in class that the message bezier() sent to a Prism object will instruct it to treat its profile as a set of control points for one or more Bézier curves, rather than as a straight-sided polygon. We will use this construct to build panes of glass, some with curved sides, that fit together to form a stained glass window.

I would like to collect all of our windows into a larger model, so please follow the guidelines below very carefully to facilitate this. Like we did with the marbles, your windows will be built as shared models.

• Your window model should be developed in a shared model file named with your name and "Window.py", so mine would be called "TerescoWindow.py". Your Group object that represents the window should be named with some representation of your name, followed by Window. I chose JTWindow. You are strongly encouraged to download and use my shared model as a starting point: TerescoWindow.py.

  Important: your shared model should not add anything to the scene. It should only add things to your shared model Group. It should not use the camera.

• Also download my WindowSetting.py file that will allow you to show off your window for testing and for creation of images for your wiki page. There are only two lines you should need to modify in this file, marked by "CHANGE HERE" comments.
• In your shared model file, create your window object as a Group of colored glass panes defined in a shared model.
  • 5 panes are required, but feel free to be ambitious and include more.
  • Construct most panes from Prisms.
  • At least three panes must have a curved edge.
  • The window should be 5 units thick, though you may include one or two "unusual" panes that might be a different thickness or even not be flat. You might use a different primitive object type for this pane if you wish.
  • The edges of your panes should meet exactly. However, you may wish, for up to 3 bonus points, to leave some (normally lead-filled) empty space between panes as a feature of your design and fill it in with an appropriate material. Even if you choose this option, the glass should cover almost all of the window area. In all cases, panes of glass should not overlap each other, nor should they overlap with any "filler" material.
  • The window should be square, 80 units wide and 80 units tall. It is centered across the xz-plane, with its lower left corner at the origin. That is, it should occupy space between 0 and 80 in both the x- and y-dimensions, and have half of its thickness in the positive z and half in the negative z.
  • Plan the layout of your panes carefully. Use graph paper to aid in your planning.
  • Give your window a formal title of five words or less (in the spirit of titles of stained glass windows in churches). Use the description message to set this title.
• Create new glass-like materials for your panes.
  • Pick a color of your choice. RGB colors have a fourth value that we have not used so far. It specifies how much of the light is filtered to take on the color of a transparent material as it passes through. The default value of 1 means no filtering, smaller values cause more of the light to take on the color of the material. I suggest a value around 0.6.
  • Make your glass highly transparent and perhaps slightly reflective and/or specular.
  • Set the refraction to 1.5, which is reasonable for glass.
  • Use at least three different materials in your window.

As with the marbles, you will render your model by running the WindowSetting.py program, which will in turn bring in your shared model of your window:

python3 WindowSetting.py

This is the window created by that file when run with my shared model of a window:

Please note: my example window does not satisfy the requirements for 5 panes (it has only 3) or 3 panes with at least one curved side (it has only 2). So a simple modification of my page will not be sufficient to earn full credit.

Submission

1. Email a copy of the source code for your Ambrosia model (the Python file(s), which should always be saved with a .py extension) and your best image (which should always be saved in PNG format and using a .png extension) as attachments to terescoj AT strose.edu. Please include a meaningful subject line (something like "CSC 112 Studio/Lab 8 Submission"). Make sure your name is included in a comment in your model code, and that you have comments throughout the source code to make it easier to understand.
2. Rename your best image to include your name, then upload it to the wiki. For example, if you generate an image of a window with smiley faces and your name is Guy Smiley, you might call your image "GuySmileyHappyWindow.png".
3. Add a section to your wiki page named "Stained Glass Windows" that includes a link to your image and a description of your model that generated the image.

Grading

This assignment is worth 30 points, which are distributed as follows: