Killer Game Programming in Java

Application Timing Results

This version of WormChase is a windowed application, with an animation loop driven by the Java 3D timer. Can it support frame rates of 80 to 85 FPS?

I consider the average UPS, which gives an indication of the speed of the game. Table 3-1 shows the FPS and UPS figures for different requested FPS amounts, on different versions of Windows.

Table 3-1. Average FPS/UPSs for the windowed WormChase using the Java 3D timer

Requested FPS	20	50	80	100
Windows 98	20/20	48/50	81/83	96/100
Windows 2000	20/20	43/50	59/83	58/100
Windows XP	20/20	50/50	83/83	100/100

Each test was run three times on a lightly loaded machine, executing for a few minutes.

The numbers are for the machines hosting Windows 98 and XP, but the frame rates on the Windows 2000 machine plateaus at about 60. This behavior is probably due to the extreme age of the machine: a Pentium 2 with a paltry 64 MB of RAM. On a more modern CPU, the frame rates are similar to the XP row of Table 3-1.

A requested frame rate of 80 is changed to 83.333 inside the program, explaining why the 80's column shows numbers close to 83 in most cases. The frame rate is divided into 1,000 using integer division, so that 1000/80 becomes 12. Later, this period value is converted back to a frame rate using doubles, so 1000.0/12 becomes 83.3333.

The Windows 2000 figures show that slow hardware is an issue. The processing power of the machine may not deliver the requested frame rate due to excessive time spent in ...