Hi Peter,
glFloat is Single.
If you want to use the c headers included in inc/glo2/gl then glfloat is already defined for you.
If your width and height are long then Oxygen will automatically convert them when making a gl call but I recommend using single for most of the graphical variables.
Even color values (0..1.0)
glcolor4f .5, .5, .7, .5
etc
Charles