Problem Set 1
CMSC 427
Distributed Tuesday, February 8, 2005
Due: Tuesday, February 22, 2005
Programming
1. 20 points. Modify the program from problem set 1 so that you can rotate the
square. Remove the previous functionality of the right mouse, so that clicking it
no longer creates a diamond. Instead, clicking the right mouse and holding it
down should enable rotation about the center of the square. More precisely, let p1
be the center point of the square. Let p2 be the location of the mouse when you
click on the right button. Let p3 be the position the mouse is moved to while
holding the right button. The square should be rotated by the angle formed by
(p2,p1,p3). The rotation should be either clockwise or counterclockwise,
depending on the direction the mouse was moved. When you release the mouse’s
right button, the rectangle should remain in its final position.
Hint: There are a number of reasonable ways to do this. One is to set up a new
coordinate system when the right mouse is clicked, and then as it moves,
determine its position relative to this coordinate system.
3D Motion: We are giving you skeleton code that will display a rectanguloid on the
screen. You will enhance this code to add more rectanguloids, to change the type of
projection, and to allow yourself to navigate about the scene. Note that included in
the code that we give you is a file vector3.cpp that contains many useful functions for
vectors, including functions to perform rotations.
2. 10 points. Implement keyboard interaction that allows you to change the
projection mode. Typing ‘p’ should change projection to perspective. Typing ‘o’
should change back to orthographic.
3. 10 points. Add four more rectanguloids to the scene, each with a different color,
shape, and position.
4. 10 points Implement a mouse control to allow you to move forward or back in the
scene. Holding down the left mouse button should move you forward slowly.
Holding down the right mouse should move you back. Holding both buttons
should cause no movement. Throughout the assignment, do not worry about what
happens if your motion takes you through a rectanguloid.
5. 10 points. Now implement rotations about your Up axis. If any mouse buttons
are being held, moving the mouse to the left or right should cause your viewpoint
to rotate about the viewer's Up axis by an amount proportional to the distance the
mouse was moved. This action should interact properly with part 4 - that is, after
you have rotated, the motion will be in the direction that you are currently
pointing.
6. 10 points. Now implement a second rotation. Moving the mouse forward will
cause you to rotate up. More precisely, your rotation will be about an axis that is
orthogonal to the Up axis and to the viewing direction. Moving the mouse back
will cause you to rotate down. Again, this should interact properly with the rest
