CMSI 3710: Quiz 1

Problem	You got	Out of
1		20
2		20
3		20
4		20
5		20
TOTAL		100

The call glOrtho(-1, 1, -1, 1, -1, 1) does not generate the default projection. Give the glOrtho call that does.
Write an OpenGL function to draw a "hot dog" (the kind of processed meat-like thing some people eat). The hot dog must be constructed from a cylinder and two spheres. The function's parameters must include a quadric object for generating the cylinder, the length of the hot dog, the width of the hot dog, the number of slices and the number of stacks. You probably haven't used gluCylinder before, so this problem is testing how well you can pick up a book or visit some online help and integrate a new concept quickly while building an OpenGL application.
Suppose you had written an OpenGL program that simply drew a nice soccer ball in the middle of the viewport.
1. If your projection matrix had been defined with gluPerspective(fovy,a,n,f) with n>0 and f>0, then you modified the code to make n smaller, but still larger than 0, recompiled and reran the program, would the new soccer ball look larger or smaller than the original? Explain.
2. If your projection matrix had been defined with glFrustum(x1,x2,y1,y2,n,f) with n>0 and f>0, then you modified the code to make n smaller, but still larger than 0, recompiled and reran the program, would the new soccer ball look larger or smaller than the original? Explain.
The advantage of parameterizing sphere and torus drawing functions with both slices and stacks is obvious: the more of each you have, the less you notice the polygonal approximation. But why do we need to specify stacks for cones?
One of the freshmen is just learning OpenGL, and defines a nice house right at the origin, sitting on the xz plane, with a height of 1 unit, say. To simulate walking around the house, the student includes an animation loop containing the line
```
    gluLookAt(10*cos(u), 0.5, 10*sin(u), 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
```
This works fine. Then the student tries to get fancy and changes the animation loop to
```
    gluLookAt(0, 10*cos(u), 10*sin(u), 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
```
What problems could occur here?