add math easing package

1 files changed, 466 insertions, 0 deletions

diff --git a/core/math/ease/ease.odin b/core/math/ease/ease.odin
new file mode 100644
index 000000000..0fe59f9d2
--- /dev/null
+++ b/core/math/ease/ease.odin
@@ -0,0 +1,466 @@
+package ease
+
+import "core:math"
+import "core:intrinsics"
+import "core:time"
+
+@(private) PI_2 :: math.PI / 2
+
+// converted to odin from https://github.com/warrenm/AHEasing
+// with additional enum based call
+
+// Modeled after the parabola y = x^2
+quadratic_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p * p
+}
+
+// Modeled after the parabola y = -x^2 + 2x
+quadratic_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return -(p * (p - 2))
+}
+
+// Modeled after the piecewise quadratic
+// y = (1/2)((2x)^2)             ; [0, 0.5)
+// y = -(1/2)((2x-1)*(2x-3) - 1) ; [0.5, 1]
+quadratic_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 2 * p * p;
+	}	else {
+		return (-2 * p * p) + (4 * p) - 1
+	}
+}
+
+// Modeled after the cubic y = x^3
+cubic_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p * p * p
+}
+
+// Modeled after the cubic y = (x - 1)^3 + 1
+cubic_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	f := p - 1
+	return f * f * f + 1
+}
+
+// Modeled after the piecewise cubic
+// y = (1/2)((2x)^3)       ; [0, 0.5)
+// y = (1/2)((2x-2)^3 + 2) ; [0.5, 1]
+cubic_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 4 * p * p * p
+	} else {
+		f := (2 * p) - 2
+		return 0.5 * f * f * f + 1
+	}
+}
+
+// Modeled after the quartic x^4
+quartic_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p * p * p * p
+}
+
+// Modeled after the quartic y = 1 - (x - 1)^4
+quartic_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	f := p - 1
+	return f * f * f * (1 - p) + 1
+}
+
+// Modeled after the piecewise quartic
+// y = (1/2)((2x)^4)        ; [0, 0.5)
+// y = -(1/2)((2x-2)^4 - 2) ; [0.5, 1]
+quartic_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 8 * p * p * p * p
+	}	else {
+		f := p - 1
+		return -8 * f * f * f * f + 1
+	}
+}
+
+// Modeled after the quintic y = x^5
+quintic_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p * p * p * p * p
+}
+
+// Modeled after the quintic y = (x - 1)^5 + 1
+quintic_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	f := p - 1
+	return f * f * f * f * f + 1
+}
+
+// Modeled after the piecewise quintic
+// y = (1/2)((2x)^5)       ; [0, 0.5)
+// y = (1/2)((2x-2)^5 + 2) ; [0.5, 1]
+quintic_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 16 * p * p * p * p * p
+	}	else {
+		f := (2 * p) - 2
+		return  0.5 * f * f * f * f * f + 1
+	}
+}
+
+// Modeled after quarter-cycle of sine wave
+sine_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return math.sin((p - 1) * PI_2) + 1
+}
+
+// Modeled after quarter-cycle of sine wave (different phase)
+sine_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return math.sin(p * PI_2)
+}
+
+// Modeled after half sine wave
+sine_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return 0.5 * (1 - math.cos(p * math.PI))
+}
+
+// Modeled after shifted quadrant IV of unit circle
+circular_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return 1 - math.sqrt(1 - (p * p))
+}
+
+// Modeled after shifted quadrant II of unit circle
+circular_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return math.sqrt((2 - p) * p)
+}
+
+// Modeled after the piecewise circular function
+// y = (1/2)(1 - sqrt(1 - 4x^2))           ; [0, 0.5)
+// y = (1/2)(sqrt(-(2x - 3)*(2x - 1)) + 1) ; [0.5, 1]
+circular_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 0.5 * (1 - math.sqrt(1 - 4 * (p * p)))
+	}	else {
+		return 0.5 * (math.sqrt(-((2 * p) - 3) * ((2 * p) - 1)) + 1)
+	}
+}
+
+// Modeled after the exponential function y = 2^(10(x - 1))
+exponential_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p == 0.0 ? p : math.pow(2, 10 * (p - 1))
+}
+
+// Modeled after the exponential function y = -2^(-10x) + 1
+exponential_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p == 1.0 ? p : 1 - math.pow(2, -10 * p)
+}
+
+// Modeled after the piecewise exponential
+// y = (1/2)2^(10(2x - 1))         ; [0,0.5)
+// y = -(1/2)*2^(-10(2x - 1))) + 1 ; [0.5,1]
+exponential_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p == 0.0 || p == 1.0 {
+		return p
+	}
+	
+	if p < 0.5 {
+		return 0.5 * math.pow(2, (20 * p) - 10)
+	} else {
+		return -0.5 * math.pow(2, (-20 * p) + 10) + 1
+	}
+}
+
+// Modeled after the damped sine wave y = sin(13pi/2*x)*pow(2, 10 * (x - 1))
+elastic_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return math.sin(13 * PI_2 * p) * math.pow(2, 10 * (p - 1))
+}
+
+// Modeled after the damped sine wave y = sin(-13pi/2*(x + 1))*pow(2, -10x) + 1
+elastic_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return math.sin(-13 * PI_2 * (p + 1)) * math.pow(2, -10 * p) + 1
+}
+
+// Modeled after the piecewise exponentially-damped sine wave:
+// y = (1/2)*sin(13pi/2*(2*x))*pow(2, 10 * ((2*x) - 1))      ; [0,0.5)
+// y = (1/2)*(sin(-13pi/2*((2x-1)+1))*pow(2,-10(2*x-1)) + 2) ; [0.5, 1]
+elastic_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 0.5 * math.sin(13 * PI_2 * (2 * p)) * math.pow(2, 10 * ((2 * p) - 1))
+	} else {
+		return 0.5 * (math.sin(-13 * PI_2 * ((2 * p - 1) + 1)) * math.pow(2, -10 * (2 * p - 1)) + 2)
+	}
+}
+
+// Modeled after the overshooting cubic y = x^3-x*sin(x*pi)
+back_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return p * p * p - p * math.sin(p * math.PI)
+}
+
+// Modeled after overshooting cubic y = 1-((1-x)^3-(1-x)*sin((1-x)*pi))
+back_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	f := 1 - p
+	return 1 - (f * f * f - f * math.sin(f * math.PI))
+}
+
+// Modeled after the piecewise overshooting cubic function:
+// y = (1/2)*((2x)^3-(2x)*sin(2*x*pi))           ; [0, 0.5)
+// y = (1/2)*(1-((1-x)^3-(1-x)*sin((1-x)*pi))+1) ; [0.5, 1]
+back_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		f := 2 * p
+		return 0.5 * (f * f * f - f * math.sin(f * math.PI))
+	} else {
+		f := (1 - (2*p - 1))
+		return 0.5 * (1 - (f * f * f - f * math.sin(f * math.PI))) + 0.5
+	}
+}
+
+bounce_in :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	return 1 - bounce_out(1 - p)
+}
+
+bounce_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 4/11.0 {
+		return (121 * p * p)/16.0
+	}	else if p < 8/11.0 {
+		return (363/40.0 * p * p) - (99/10.0 * p) + 17/5.0
+	}	else if p < 9/10.0 {
+		return (4356/361.0 * p * p) - (35442/1805.0 * p) + 16061/1805.0
+	}	else {
+		return (54/5.0 * p * p) - (513/25.0 * p) + 268/25.0
+	}
+}
+
+bounce_in_out :: proc "contextless" (p: $T) -> T where intrinsics.type_is_float(T) {
+	if p < 0.5 {
+		return 0.5 * bounce_in(p*2)
+	} else {
+		return 0.5 * bounce_out(p * 2 - 1) + 0.5
+	}
+}
+
+// additional enum variant
+
+Ease :: enum {
+	Linear,
+
+	Quadratic_In,
+	Quadratic_Out,
+	Quadratic_In_Out,
+
+	Cubic_In,
+	Cubic_Out,
+	Cubic_In_Out,
+
+	Quartic_In,
+	Quartic_Out,
+	Quartic_In_Out,
+
+	Quintic_In,
+	Quintic_Out,
+	Quintic_In_Out,
+
+	Sine_In,
+	Sine_Out,
+	Sine_In_Out,
+
+	Circular_In,
+	Circular_Out,
+	Circular_In_Out,
+
+	Exponential_In,
+	Exponential_Out,
+	Exponential_In_Out,
+
+	Elastic_In,
+	Elastic_Out,
+	Elastic_In_Out,
+
+	Back_In,
+	Back_Out,
+	Back_In_Out,
+
+	Bounce_In,
+	Bounce_Out,
+	Bounce_In_Out,
+}
+
+ease :: proc "contextless" (type: Ease, p: $T) -> T 
+	where intrinsics.type_is_float(T) {
+	switch type {
+		case .Linear: return p
+		
+		case .Quadratic_In: return quadratic_in(p)
+		case .Quadratic_Out: return quadratic_out(p)
+		case .Quadratic_In_Out: return quadratic_in_out(p)
+
+		case .Cubic_In: return cubic_in(p)
+		case .Cubic_Out: return cubic_out(p)
+		case .Cubic_In_Out: return cubic_in_out(p)
+
+		case .Quartic_In: return quartic_in(p)
+		case .Quartic_Out: return quartic_out(p)
+		case .Quartic_In_Out: return quartic_in_out(p)
+
+		case .Quintic_In: return quintic_in(p)
+		case .Quintic_Out: return quintic_out(p)
+		case .Quintic_In_Out: return quintic_in_out(p)
+
+		case .Sine_In: return sine_in(p)
+		case .Sine_Out: return sine_out(p)
+		case .Sine_In_Out: return sine_in_out(p)
+
+		case .Circular_In: return circular_in(p)
+		case .Circular_Out: return circular_out(p)
+		case .Circular_In_Out: return circular_in_out(p)
+
+		case .Exponential_In: return exponential_in(p)
+		case .Exponential_Out: return exponential_out(p)
+		case .Exponential_In_Out: return exponential_in_out(p)
+
+		case .Elastic_In: return elastic_in(p)
+		case .Elastic_Out: return elastic_out(p)
+		case .Elastic_In_Out: return elastic_in_out(p)
+
+		case .Back_In: return back_in(p)
+		case .Back_Out: return back_out(p)
+		case .Back_In_Out: return back_in_out(p)
+
+		case .Bounce_In: return bounce_in(p)
+		case .Bounce_Out: return bounce_out(p)
+		case .Bounce_In_Out: return bounce_in_out(p)
+	}
+
+	// in case type was invalid
+	return 0
+}
+
+Flux_Map :: struct($T: typeid) {
+	values: map[^T]Flux_Tween(T),
+}
+
+Flux_Tween :: struct($T: typeid) {
+	value: ^T,
+	start: T,
+	diff: T,
+	goal: T,
+
+	// using ticks for timing instead
+	delay_tick_start: time.Tick,
+	delay: time.Duration,
+	duration: time.Duration,
+
+	progress: f64,
+	rate: f64,
+	type: Ease,
+
+	inited: bool,
+
+	// callbacks, data can be set, will be pushed to callback
+	data: rawptr, // by default gets set to value input
+	on_start: proc(flux: ^Flux_Map(T), data: rawptr),
+	on_update: proc(flux: ^Flux_Map(T), data: rawptr),
+	on_complete: proc(flux: ^Flux_Map(T), data: rawptr),
+}
+
+// init flux map to a float type and a wanted cap
+flux_init :: proc($T: typeid, cap := 8) -> Flux_Map(T) where intrinsics.type_is_float(T) {
+	return {
+		make(map[^T]Flux_Tween(T), cap),
+	}
+}
+
+// delete map content
+flux_destroy :: proc(flux: Flux_Map($T)) where intrinsics.type_is_float(T) {
+	delete(flux.values)
+}
+
+// clear map content, stops all animations
+flux_clear :: proc(flux: ^Flux_Map($T)) where intrinsics.type_is_float(T) {
+	clear(&flux.values)
+}
+
+// append / overwrite existing tween value to parameters
+// rest is initialized in flux_tween_init, inside update
+// return value can be used to set callbacks
+flux_to :: proc(
+	flux: ^Flux_Map($T),
+	value: ^f32, 
+	goal: f32, 
+	type: Ease = .Quadratic_Out,
+	duration: time.Duration = time.Second, 
+	delay: time.Duration = 0,
+) -> (tween: ^Flux_Tween(T)) where intrinsics.type_is_float(T) {
+	if res, ok := &flux.values[value]; ok {
+		tween = res
+	} else {
+		flux.values[value] = {}
+		tween = &flux.values[value]
+	}
+
+	tween^ = { 
+		value = value, 
+		goal = goal, 
+		duration = duration,
+		delay = delay,
+		delay_tick_start = time.tick_now(),
+		type = type,
+		data = value,
+	}
+
+	return
+}
+
+// init internal properties
+flux_tween_init :: proc(tween: ^Flux_Tween($T), duration: time.Duration) where intrinsics.type_is_float(T) {
+	tween.inited = true
+	tween.start = tween.value^
+	tween.diff = tween.goal - tween.value^
+	s := time.duration_seconds(duration)
+	tween.rate = duration > 0 ? 1.0 / s : 0
+	tween.progress = duration > 0 ? 0 : 1
+}
+
+// update all tweens, wait for their delay if one exists
+// calls callbacks in all stages, when they're filled
+// deletes tween from the map after completion
+flux_update :: proc(flux: ^Flux_Map($T), dt: f64) where intrinsics.type_is_float(T) {
+	size := len(flux.values)
+	now := time.tick_now()
+
+	for key, tween in &flux.values {
+		if tween.delay != 0 {
+			diff := time.tick_diff(tween.delay_tick_start, now)
+
+			// when diff reached delay, stop delaying
+			if diff > tween.delay {
+				tween.delay = 0
+			}
+		} else {
+			if !tween.inited {
+				flux_tween_init(&tween, tween.duration)
+				
+				if tween.on_start != nil {
+					tween.on_start(flux, tween.data)
+				}
+			} 
+
+			tween.progress += tween.rate * dt
+			x := tween.progress >= 1 ? 1 : ease(tween.type, tween.progress)
+			tween.value^ = tween.start + tween.diff * T(x)
+
+			if tween.on_update != nil {
+				tween.on_update(flux, tween.data)
+			}
+
+			if tween.progress >= 1 {
+				delete_key(&flux.values, key)
+
+				if tween.on_complete != nil {
+					tween.on_complete(flux, tween.data)
+				}
+			}
+		}
+	}
+}
+
+// stop a specific key inside the map
+// returns true when it successfully removed the key
+flux_stop :: proc(flux: ^Flux_Map($T), key: ^f32) -> bool where intrinsics.type_is_float(T) {
+	if key in flux {
+		delete_key(flux, key)
+		return true
+	}
+
+	return false
+}
\ No newline at end of file