CSC 418/2504 Fall 2001 Assignment 2, Question 5.

• intersect.cpp skeleton code.
• Makefile and Makefile.cdf: needed to compile and link on the CDF system.
• intersect.dsp intersect.dsw: you don't really need these (the code doesn't use any special libraries), but they're used by Microsoft Visual C++.
• run.bat: how to invoke the program.

The program uses three data files, which have the following format:

• Camera file (here's an example): this lists the following information:
  • nearZ : the distance from the eye to the image plane (in CAMERA coordinates).
  • leftX, rightX : the left and right boundaries of the image, also in camera coordinates.
  • bottomY, topY : the bottom and top boundaries of the image, also in camera coordinates.
  • width, height : the number of PIXELS in the image, both left-right and up-down. This is in DEVICE (ie, pixel) coordinates.
• A file describing the cylinder's shape (here's an example). It lists the following parameters:
  • x,y,z : the position of the centre of the cylinder.
  • radius : the cylinder's radius.
  • height : the cylinder's height (from top to bottom).
• Finally, a file listing the pixels through which rays should be cast (here's an example). The file lists:
  • n : the number of pixels.
  • x_i,y_i : for i from 1 to n, the coordinates of the pixels themselves.

    NOTE: These are in DEVICE coordinates, and both x and y behave like ordinary cartesian coordinates. By this I mean, in particular, that y increases as you go up, the image, not down.

In the example given above, all the rays hit the BACK of the cylinder. Here is an image with three sample rays, through pixels:

• a (180,220) HIT
• b (180,180) HIT
• c (150,150) MISS

Cylinder:

• (x y z) = (1 2 -5)
• radius = 1
• height = 2

• nearZ = 1
• (leftX rightX) = (-1 1)
• (bottomY topY) = (-1 1)
• (width height) = (300 300)