Rework TimeDelta func into a simpler FPS func and remove FPS consts

meowgorithm · meowgorithm · commit d56f9e806c00 · 2021-07-09T18:24:41.000-04:00
diff --git a/examples/bubbletea/main.go b/examples/bubbletea/main.go
@@ -13,7 +13,7 @@ import (
 )
 
 const (
-	fps          = time.Second / 60
+	fps          = 60
 	spriteWidth  = 12
 	spriteHeight = 5
 	frequency    = 0.95
@@ -34,7 +34,7 @@ var (
 type frameMsg time.Time
 
 func animate() tea.Cmd {
-	return tea.Tick(fps, func(t time.Time) tea.Msg {
+	return tea.Tick(time.Second/fps, func(t time.Time) tea.Msg {
 		return frameMsg(t)
 	})
 }
@@ -94,7 +94,7 @@ func (m model) View() string {
 
 func main() {
 	m := model{
-		spring: harmonica.NewSpring(harmonica.TimeDelta(fps), frequency, damping),
+		spring: harmonica.NewSpring(harmonica.FPS(fps), frequency, damping),
 	}
 
 	if err := tea.NewProgram(m).Start(); err != nil {
diff --git a/examples/canvas/main.go b/examples/canvas/main.go
@@ -50,7 +50,7 @@ func main() {
 
 				circ = Circle{
 					// Setup a new spring.
-					spring: harmonica.NewSpring(harmonica.TimeDelta(time.Second/fps), frequency, damping),
+					spring: harmonica.NewSpring(harmonica.FPS(fps), frequency, damping),
 
 					// Set target radius.
 					Radius: circleRadius,
diff --git a/harmonica.go b/harmonica.go
@@ -4,8 +4,8 @@
 //
 // Example usage:
 //
-//     // Run once to initialize. Note the FPS.
-//     spring := NewSpring(FPS60, 0.8, 1.0)
+//     // Run once to initialize.
+//     spring := NewSpring(FPS(60), 0.8, 1.0)
 //
 //     // Update on every frame.
 //     pos := 0.0
@@ -55,22 +55,16 @@ import (
 	"time"
 )
 
-// Standard time deltas that can be used when initializing a spring.
-const (
-	FPS60 = float64(int64(time.Second/60)) / float64(int64(time.Second))
-	FPS30 = float64(int64(time.Second/30)) / float64(int64(time.Second))
-)
-
-// TimeDelta returns a time delta for a given FPS. This is usefaul for setting
-// the time delta when initializing a Spring.
+// FPS returns a time delta for a given number of frames per second. This value
+// can be used as the time delta when initializing a Spring.
 //
 // Example:
 //
-//      delta := TimeDelta(time.Second/60)
-//      spring := New(delta, 0.98, 0.8)
+//     spring := NewSpring(FPS(60), 0.8, 0.98)
 //
-func TimeDelta(fps time.Duration) float64 {
-	return float64(int64(fps)) / float64(int64(time.Second))
+func FPS(n int) float64 {
+	d := time.Second / time.Duration(n)
+	return float64(int64(d)) / float64(int64(time.Second))
 }
 
 // In calculus ε is (in vague terms) an arbitrarily small positive number. In
