Game Development Reference
In-Depth Information
In
y ¼ a
,
a
identifies a constant value. When you plot such a function, the graph
assumes the form shown in Figure 10.8. You equate the lines this figure shows as
a flat slope. In other words, the slope has no rise, only a run. For all values of
x
,
y
remains the same.
To use Visual Formula to plot constant values, click on the Value menu item.
Then click in the upper equation composition area to position the Value field.
Type 5 in the field. The equation you implement takes the form of
y ¼ a
,asis
illustrated in Figure 10.8. Click the Chart for Formula 1 button to view the graph.
Figure 10.9 illustrates the result.
To generate the lower line in the Cartesian plane, click the Value menu item.
Then click in the lower of the two equation composition areas. In the field that
results, type
3. Then in the lower-right panel, Click Chart for Formula 2. As
Figure 10.9 illustrates, the lower line is beneath and parallel to the
x
axis.
Figure 10.9
Generate parallel lines by setting the y value to a constant.
