CMPS 160 -- Lab Assignment 2

Due date:
Midnight, Friday, April 10, 2015

Objectives:

Description

• Organize your lab1 javascript code so that you now have a triangle function that draws a single triangle wireframe given 3 vertices, using a predefined color.
• You will use your new triangle drawing primitive in 2 ways: (a) draw random triangles, and (b) create recursively subdivided triangles.
• Random Triangles:
  • Create a button called "Random" so that each time it is pressed, the display is cleared and 10 triangles are displayed.
  • Use the random number generator to generate coordinates for each of the triangle vertex.
• Subdivided Triangles:
  • Create another button called "Subdivide" so that each time it is pressed, the triangle(s) are subdivided and displayed.
  • The first time this button is pressed, a single triangle is drawn. The coordinates may either be hardwired or generated randomly.
  • Each successive presses of this button, will subdivide each of the current set of triangles into 4 triangles using the following strategy. To subdivide a triangle into 4, find the midpoint along each edge of the triangle. Use these 3 new points as vertices for a new triangle. The other three triangles will use one of the existing vertex, and 2 of the new vertices as their vertices.
• Button States:
  • If the display is currently showing subdivided triangles and the "Random" button is pressed, it will simply throw away the subdivided triangles and generate 10 new random triangles.
  • If the display is currently showing random triangles and the "Subdivide" button is pressed, it will throw away the last set of 10 random triangles, and display a single new triangle.
  • If the display is currently showing a single triangle or more subdivided triangles, and the "Subdivide" button is pressed, then new triangles are added to the set of subdivided triangles.
  • One way to do this is keep track of the last "state" of the button press. That is, remember whether it was "Random" or "Subdivide". This idea of a "state" is also used in the OpenGL / WebGL API.

Grading:

Comments (header block and inline comments for javascript) will account for 20% of grade. Remaining 80% for functionality, split 50-50 between random and subdivided triangles.

The header block should contain at least the following information: name, cruzid, date, and brief description of your program. This will be true for all future assignments and programs.

Rubric:

5	comment block
5	separation of javascript from html
10	inline comments
40	random triangles and button events
40	subdivided triangles and button events

Who graded your assignment:

Submission:

• submit cmps160-ap.s15 lab2 lab2.tar, or
• submit cmps160-ap.s15 lab2 lab2.zip

This command should work from unix.ic.ucsc.edu. Create and submit a subdirectory called lab2. It should contain all the files necessary for this program run. Tar or zip up lab2 before submitting.

Last modified Sunday, 05-Apr-2015 18:25:24 PDT.