Flash MX 2004 Games : Art to ActionScript

Flash MX 2004 Games
Figure B.9 Piecewise curve fitting
The curve we will use is
y = h0 ∗ K1 + h1 ∗ K2 + h2 ∗ T1 + h3 ∗ T2
where h0 to h3 are the hermite coefficients:
h0 = 2t 3 − 3t 2 + 1
h1 = 3t 2 − 2t 3
h2 = t 3 − 2t 2 + t
h3 = t 3 − t 2
and T1 and T2 are the smoothing parameters. If S1 and S2 are defined as:
then
S1 = (K2.time − K1.time)/(K2.time − K0.time)
S1 = (K2.time − K1.time)/(K3.time − K1.time)
T1 = S1 ∗ ((1 − K1.tn)(1 + K1.bs)(1 + K1.ct)(K1.value − K0.value)
+ (1 − K1.tn)(1 − K1.bs)(1 − K1.ct)(K2.value − K1.value))
T2 = S2 ∗ ((1 − K2.tn)(1 + K2.bs)(1 − K1.ct)(K2.value − K1.value)
+ (1 − K2.tn)(1 − K2.bs)(1 + K2.ct)(K3.value − K2.value))
If the curve section is between K0 and K1, then
406
T1 = 0.5 ∗ (K2.value − K1.value) ∗ ((1 − K1.tn)(1 + K1.bs)(1 + K1.ct)
+ (1 − K1.tn)(1 − K1.bs)(1 − K1.ct))