3D Engine for Dummies - Page 9

The Routine

Now comes the real part: the engine program itself.

The loading setup
First we are going to create the initiation routine, the one that starts it all out. Open the second key-frame of the actions layer. This is what we do:

• move the baseline instance so that no one can see it on the picture.

  Set Property ("/baseline", X Position) = "1000"

• then let's cut the points variable up into lots of separate coordinate variables:

  Set Variable: "n" = "1"
  Loop While (n <= totalpoints)
        Set Variable: "x"&n = Substring (points,( (n-1) * 12 + 1), 3 )
        Set Variable: "y"&n = Substring (points, ((n-1 ) * 12 + 5), 3 )
        Set Variable: "z"&n = Substring (points, ((n-1) * 12 + 9), 3 )
        Set Variable: "n" = n+1
  End Loop

  This places the x-coordinate of point 1 in variable x1, the y-coordinate in y1, the z in z1 and the same thing for all other points.
• now we do the same thing for the lines variable:

  Set Variable: "n" = "1"
  Loop While (n <=totallines)
        Set Variable: "pt1"&n = Substring (lines, (n-1)*5+1, 2 )
        Set Variable: "pt2"&n = Substring (lines, (n-1)*5+3, 2 )
        Set Variable: "n" = n+1
  End Loop

  The first end of point 1 is put in pt11, the second one in pt21, etc.
• set the center of the display. These are the coordinates of point (0,0) in the movie.

  Set Variable: "centerx" = "190"
  Set Variable: "centery" = "215"