3D Engine for Dummies - Page 14

The Rotations

This is the last thing we have to do to have our functional 3D engine. The rotation works in a similar way to the zoom. We set two basic basesin and basecos variables. These contain the values of sin 10° and cos 10°. Then while one of the rotation buttons is rolled over the coordinates of all points are rotated around the corresponding axis by 10° at each loop. The rotation frames work with a sin variable and a cos variable, so the zoombuttons only load values in sin and cos and set an axis variable to x, y or z depending on the axis that should be rotated around.

First we modify the start frame. After all the rest we first set the basesin and basecos:

Set Variable: "basecos" = 0.9848
Set Variable: "basesin" = 0.1736

Set Variable: "sin" = basesin
Set Variable: "cos" = basecos
Call ("rotx")
Call ("roty")

Now we change the loop frame. Add this:

Call ("rot"&axis)