Playing around with some heightfields, bumpmapping and shadowcasting...

The 'zstest' program understands the following command line options:
 -d Double buffered display
 -f Full screen display
 -hw Hardware display surface
 -w<n> Display width = <n> pixels
 -h<n> Display height = <n> pixels
 -t<n> Terraing generator start tile size = <n> pixels

When running, the 'zstest' program responds to the followin keys:
 Mouse Cycle display modes ()
 F1 Display mode 0: 2D or 3D, depending on pitch
 F2 Display mode 1: Z graphs
 F3 Display mode 2: Z channel
 F4 Display mode 3: Intensity channel

 B Toggle bump mapping
 S Toggle shadow casting
 T Toggle objects
 Space Toggle scene morphing

 Up Pitch up
 Down Pitch down

 Left Decrease sun altitude
 Right Increase sun altitude

 * Double scale (display modes 1 & 2)
 / Half scale (display modes 1 & 2)

 + Increase terrain detail
 - Decrease terrain detail

 PgUp Increase terrain height
 PgDown Decrease terrain height

 Home Raise terrain base level
 End Lower terrain base level

 Ins Raise sea level
 Del Lower sea level

 Sh+Ins Increase fog denseness
 Sh+Del Decrease fog denseness