Game Development Reference
In-Depth Information
Figure 6-4. Projectile dropped from a moving system
Table 6-4 shows the formulas to use to solve this type of problem. Note here that when
v o is 0, the problem reduces to a simple free-fall problem in which the projectile drops
straight down.
Table 6-4. Formulas—projectile dropped from a moving system
To calculate: Use this formula:
x(t) v o t
y(t) h - (g t 2 ) / 2
v x (t) v o
v y (t) - g t
v(t) v 0 2
+ g 2 t 2
h
(g t 2 ) / 2
R
v o T
T
2 h
g
These formulas are useful if you're writing a game that does not require a more accurate
treatment of projectile motion—that is, if you don't need or want to consider the other
forces that can act on a projectile when in motion. If you are going for more accuracy,
you'll have to consider these other forces and treat the problem as we did in Chap‐
ter 4 's example.
Drag
In Chapter 3 and Chapter 4 , we showed you the idealized formulas for viscous fluid
dynamic drag as well as how to implement drag in the equations of motion for a pro‐