3D Engine for Dummies - Page 10

The Routine (con't)

The loop
Next we are just going to set up the basic loop. This will be used later for the zoom and the rotations. Open the 4th frame loop2 and enter

Go to and Play ("loop")

The zoom routine (part 1)
We now have to make a basic zoom routine to transform the zoom value in percent into the z-coordinate of the view plane. We'll make the zoom buttons in a while. They way we do our conversion is to take a percent of the distance between the eyez (minimal zoom position) and the maxzoom position, and add the maxzoom. This way the z of the view plane takes values between eyez and maxzoom when the zoom takes values between 0 and 100 percent. Open the next to last keyframe zoom and enter this:

Set Variable: "depth" = - zoom * (eyez -maxzoom) / 100 + eyez
Call ("draw")

Set Variable: "zoomvalue" = "zoom= " & zoom & "%"

The drawline routine
This is the last thing we have to do before the drawing routine it self. This routine will be used to draw the line linking two points. The way it works is that the baseline is duplicated and its size and position are adjusted to correspond to the points (it works, that's all that counts).

Set Variable: "pt1" = eval("pt1"&n)
Set Variable: "pt2" = eval("pt2"&n)
Set Property ("line"&n, X Position) = eval("2Dx"&pt1)
Set Property ("line"&n, Y Position) = eval("2Dy"&pt1)
Set Property ("line"&n, X Scale) = eval("2Dx"&pt2) - eval("2Dx"&pt1)
Set Property ("line"&n, Y Scale) = eval("2Dy"&pt2) - eval("2Dy"&pt1)