Game Development Reference
In-Depth Information
When you play the Golf Game, select different clubs and impact velocities and see what
happens. Keep in mind that because the clubs are different lengths that a realistic impact
velocity will be different for different clubs. A professional golfer might be able to swing a driver
such that the impact velocity is 50
m/s
, but he or she (or you) would be unable to swing a 7 iron
with the same impact velocity.
An interesting effect occurs if the impact velocity is set too high for a given loft angle. The
spin rate will be high enough such that the resulting Magnus force will significantly exceed the
force of gravity over part of the flight of the ball, causing a sharper peak in the ball trajectory.
This type of shot is known as a “blow-up” shot, and a typical example is shown in Figure 7-9.
Figure 7-9.
A blow-up shot results from too much spin on the ball.
Putting
At the end of every golf hole is an area of tightly mowed grass known as the
green
. The objective
of golf is to hit the ball into a hole located on the green. Once the ball is on the green (or some-
times even if it is off the green), a shot called a putt is performed to roll the ball towards the
hole. Putters are clubs with low loft angles—3 degrees is a typical number. The putter club head
mass can vary quite a bit, but a typical value is 0.33
kg
. The green upon which the ball rolls is an
area of closely mowed grass that can slope in any direction. The movement of the golf ball after
it is putted can be broken up into three segments—the impact phase, the skid phase, and the
roll phase.
