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More readable variable names

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This commit is contained in:
Christian Rocha 2021-07-13 21:36:02 -04:00
parent 0b6d573edd
commit 62c83bf96a
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GPG Key ID: D6CC7A16E5878018
1 changed files with 29 additions and 21 deletions
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harmonica.go
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@ -71,12 +71,12 @@ func FPS(n int) float64 {
//
// const float epsilon = 0.0001
//
// We could also represent ε as:
// Some Go programmers use:
//
// const epsilon float64 = 0.00000001
//
// In Go, however, we can calculate the machine’s epsilon value, with the
// drawback that it must be a variable versus a constant.
// We can, however, calculate the machine’s epsilon value, with the drawback
// that it must be a variable versus a constant.
var epsilon = math.Nextafter(1, 2) - 1
// Spring contains a cached set of motion parameters that can be used to
@ -104,6 +104,14 @@ type Spring struct {
// New initializes a new Spring, computing the parameters needed to simulate
// a damped spring over a given period of time.
//
// The delta time is the time step to advance; essentially the framerate.
//
// The angular frequency is the angular frequency of motion, which affects the
// speed.
//
// The damping ratio is the damping ratio of motion, which determines the
// oscillation, or lack thereof. There are three categories of damping ratios:
//
// Damping ratio > 1: over-damped.
// Damping ratio = 1: critlcally-damped.
// Damping ratio < 1: under-damped.
@ -142,20 +150,20 @@ func NewSpring(deltaTime, angularFrequency, dampingRatio float64) (s Spring) {
e1 = math.Exp(z1 * deltaTime)
e2 = math.Exp(z2 * deltaTime)
invTwoZb = 1.0 / (2.0 * zb)
invTwoZb = 1.0 / (2.0 * zb) // = 1 / (z2 - z1)
e1OverTwoZb = e1 * invTwoZb
e2OverTwoZb = e2 * invTwoZb
e1_Over_TwoZb = e1 * invTwoZb
e2_Over_TwoZb = e2 * invTwoZb
z1e1OverTwoZb = z1 * e1OverTwoZb
z2e2OverTwoZb = z2 * e2OverTwoZb
z1e1_Over_TwoZb = z1 * e1_Over_TwoZb
z2e2_Over_TwoZb = z2 * e2_Over_TwoZb
)
s.posPosCoef = e1OverTwoZb*z2 - z2e2OverTwoZb + e2
s.posVelCoef = -e1OverTwoZb + e2OverTwoZb
s.posPosCoef = e1_Over_TwoZb*z2 - z2e2_Over_TwoZb + e2
s.posVelCoef = -e1_Over_TwoZb + e2_Over_TwoZb
s.velPosCoef = (z1e1OverTwoZb - z2e2OverTwoZb + e2) * z2
s.velVelCoef = -z1e1OverTwoZb + z2e2OverTwoZb
s.velPosCoef = (z1e1_Over_TwoZb - z2e2_Over_TwoZb + e2) * z2
s.velVelCoef = -z1e1_Over_TwoZb + z2e2_Over_TwoZb
} else if dampingRatio < 1.0-epsilon {
// Under-damped.
@ -169,16 +177,16 @@ func NewSpring(deltaTime, angularFrequency, dampingRatio float64) (s Spring) {
invAlpha = 1.0 / alpha
expSin = expTerm * sinTerm
expCos = expTerm * cosTerm
expOmegaZetaSinOverAlpha = expTerm * omegaZeta * sinTerm * invAlpha
expSin = expTerm * sinTerm
expCos = expTerm * cosTerm
expOmegaZetaSin_Over_Alpha = expTerm * omegaZeta * sinTerm * invAlpha
)
s.posPosCoef = expCos + expOmegaZetaSinOverAlpha
s.posPosCoef = expCos + expOmegaZetaSin_Over_Alpha
s.posVelCoef = expSin * invAlpha
s.velPosCoef = -expSin*alpha - omegaZeta*expOmegaZetaSinOverAlpha
s.velVelCoef = expCos - expOmegaZetaSinOverAlpha
s.velPosCoef = -expSin*alpha - omegaZeta*expOmegaZetaSin_Over_Alpha
s.velVelCoef = expCos - expOmegaZetaSin_Over_Alpha
} else {
// Critically damped.
@ -199,9 +207,9 @@ func NewSpring(deltaTime, angularFrequency, dampingRatio float64) (s Spring) {
}
// Update updates position and velocity values against a given target value.
// Call this after calling New to update values.
func (s Spring) Update(pos, vel *float64, equilibriumPos float64) {
oldPos := *pos - equilibriumPos
// Call this after calling NewSpring to update values.
func (s Spring) Update(pos *float64, vel *float64, equilibriumPos float64) {
oldPos := *pos - equilibriumPos // update in equilibrium relative space
oldVel := *vel
*pos = oldPos*s.posPosCoef + oldVel*s.posVelCoef + equilibriumPos