StageTools - Documentation (CenterStage/Tutorial)

Now that you have a surface, lets make it more interactive. Suppose you are interested in the family of surfaces f(x,y) = x³ - ax - y² for various values of a. We can make a slider for the value of a so that changing the slider changes the surface. To do this, edit the function to be

    Function {x y} {
      let z = x^3 - a x - y^2
    }

and below this add the line

    Slider a -1 1 0

This declares a slider tied to the variable a whose values run from -1 to 1 and is set initially to 0. When you hit the Update button, the slider will appear in its own window. First, move this to a convenient location, then change the value of the slider by dragging it; when you let go, the surface should be updated to reflect the new value of a.¹

Note that the values of sliders can be used almost anywhere. For instance, you can change the domain to

    Domain {{-1 1 n} {-1 1 n}}
    Slider n 1 20 10 -resolution 1

in order to have the number of subdivisions be controlled by a slider. Here, the resolution of the slider is set to 1 so that it will take on only integer values.

StageTools Documentation web pages Created: 08 Sep 2001 Last modified: 08 Sep 2001 23:35:30 Comments to: dpvc@union.edu

Combining Objects A Short CenterStage Tutorial Creating Your First Surface