lib: add ad, decay to link-time

1 files changed, 139 insertions, 40 deletions

diff --git a/alv-lib/link-time.moon b/alv-lib/link-time.moon
index 34e2220..251ee6c 100644
--- a/alv-lib/link-time.moon
+++ b/alv-lib/link-time.moon
@@ -97,6 +97,8 @@ every = Constant.meta
       if post < pre
         @out\set evt
 
+    vis: => type: 'event'
+
 lfo = Constant.meta
   meta:
     name: 'lfo'
@@ -139,39 +141,6 @@ lfo = Constant.meta
 
     vis: => type: 'bar', bar: @.out!
 
-ramp = Constant.meta
-  meta:
-    name: 'ramp'
-    summary: "Sawtooth LFO."
-    examples: { '(ramp [clock] period [phase] [max])' }
-    description: "Ramps from `0` to `max` once every `period` beats.
-
-- `clock` should be a `time/clock!` stream. This argument can be omitted
-  and the stream be passed as a dynamic definition in `*clock*` instead.
-- `period` should be a num~ stream.
-- `phase` should be a num~ stream and defaults to 0.
-- `max` should be a num~ stream and defaults to `period` if omitted."
-  value: class extends Op
-    pattern = -sig['link/clock'] + sig.num + -sig.num + -sig.num
-    setup: (inputs, scope) =>
-      { clock, period, phase, max } = pattern\match inputs
-      super
-        clock: Input.hot clock or scope\get '*clock*'
-        period: Input.cold period
-        phase: Input.cold phase or Constant.num 0
-        max: max and Input.cold max
-
-      @setup_out '~', T.num, 0
-
-    tick: =>
-      { :clock, :period, :phase, :max } = @unwrap_all!
-      t = clock.state\phase_at_time clock.time, period
-      t = (t - phase) / period % 1
-      max or= period
-      @out\set t * max
-
-    vis: => type: 'bar', bar: @state
-
 tick = Constant.meta
   meta:
     name: 'tick'
@@ -214,20 +183,20 @@ phase = Constant.meta
   meta:
     name: 'phase'
     summary: "Get phase."
-    examples: { '(tick [clock] period)' }
-    description: "Counts upwards by one every `period` beats.
+    examples: { '(tick [clock] period [phase])' }
+    description: "Ramps from `0` to `period` once every `period` beats.
 
 - `clock` should be a `link/clock~` stream. This argument can be omitted
   and the stream be passed as a dynamic definition in `*clock*` instead.
-- `period` should be a num~ stream and defaults to 1.
-- returns a `num~` stream that ticks from 0 to `period`."
+- `period` should be a num~ stream.
+- `phase` should be a num~ stream and defaults to 0."
   value: class extends Op
-    pattern = -sig['link/clock'] + -sig.num + -sig.num
+    pattern = -sig['link/clock'] + sig.num + -sig.num
     setup: (inputs, scope) =>
       { clock, period, phase } = pattern\match inputs
       super
         clock: Input.hot clock or scope\get '*clock*'
-        period: Input.cold period or Constant.num 0
+        period: Input.cold period
         phase: Input.cold phase or Constant.num 0
 
       @setup_out '~', T.num
@@ -241,8 +210,136 @@ phase = Constant.meta
 
       @out\set t
 
-    vis: => type: 'event'
+    vis: => type: 'bar', bar: @.out! / @inputs.period!
+
+ramp = Constant.meta
+  meta:
+    name: 'ramp'
+    summary: "Get normalized phase."
+    examples: { '(ramp [clock] period [phase])' }
+    description: "Ramps from `0` to `1` once every `period` beats.
+
+- `clock` should be a `time/clock!` stream. This argument can be omitted
+  and the stream be passed as a dynamic definition in `*clock*` instead.
+- `period` should be a num~ stream.
+- `phase` should be a num~ stream and defaults to 0."
+  value: class extends Op
+    pattern = -sig['link/clock'] + sig.num + -sig.num
+    setup: (inputs, scope) =>
+      { clock, period, phase } = pattern\match inputs
+      super
+        clock: Input.hot clock or scope\get '*clock*'
+        period: Input.cold period
+        phase: Input.cold phase or Constant.num 0
+
+      @setup_out '~', T.num
+
+    tick: =>
+      { :clock, :period, :phase, :evt } = @unwrap_all!
+      return if period == 0
+
+      t = clock.state\phase_at_time clock.time, period
+      t = (t + period - phase) % period
+
+      @out\set t / period
+
+    vis: => type: 'bar', bar: @.out!
+
+decay = Constant.meta
+  meta:
+    name: 'decay'
+    summary: "Decay envelope from bang!."
+    examples: { '(decay [clock] dur trigger)' }
+    description: "Ramp from `1` to `0` in `dur` beats on `trigger`.
+
+- `clock` should be a `link/clock~` stream. This argument can be omitted
+  and the stream be passed as a dynamic definition in `*clock*` instead.
+- `dur` should be a num~ stream.
+- `trigger` should be a bang! stream."
+  value: class extends Op
+    pattern = -sig['link/clock'] + sig.num + evt.bang
+    setup: (inputs, scope) =>
+      { clock, dur, trigger } = pattern\match inputs
+      super
+        clock: Input.hot clock or scope\get '*clock*'
+        dur: Input.cold dur
+        trigger: Input.hot trigger
+
+      @setup_out '~', T.num, 0
+      @state = math.min @inputs.dur!, (@state or 0)
+
+    tick: =>
+      { :clock, :dur, :trigger } = @unwrap_all!
 
+      if trigger
+        @state = dur
+      elseif clock
+        return if @state <= 0
+        pre = clock.state\beat_at_time clock.time - clock.dt, 1
+        post = clock.state\beat_at_time clock.time, 1
+        delta = post - pre
+        @state = math.max 0, @state - delta
+
+      @out\set @state / dur
+
+    vis: => type: 'bar', bar: @.out!
+
+ad = Constant.meta
+  meta:
+    name: 'ad'
+    summary: "Attack-Decay enveloper from bang!."
+    examples: { '(ad [clock] attack decay trigger)' }
+    description: "Ramp from `0` to `1` and back on `trigger`.
+
+- `clock` should be a `link/clock~` stream. This argument can be omitted
+  and the stream be passed as a dynamic definition in `*clock*` instead.
+- `attack` and `decay` should be num~ streams.
+- `trigger` should be a bang! stream."
+  value: class extends Op
+    pattern = -sig['link/clock'] + sig.num + sig.num + evt.bang
+    setup: (inputs, scope) =>
+      { clock, attack, decay, trigger } = pattern\match inputs
+      super
+        clock: Input.hot clock or scope\get '*clock*'
+        attack: Input.cold attack
+        decay: Input.cold decay
+        trigger: Input.hot trigger
+
+      @setup_out '~', T.num, 0
+      @state = math.min @inputs.decay!, math.max -@inputs.attack!, (@state or 0)
+
+    tick: =>
+      { :clock, :attack, :decay, :trigger } = @unwrap_all!
+
+      delta = 0
+
+      if trigger
+        @state = -attack
+      elseif clock
+        return if @state == 0
+
+        pre = clock.state\beat_at_time clock.time - clock.dt, 1
+        post = clock.state\beat_at_time clock.time, 1
+        delta = post - pre
+
+      if @state < 0
+        -- attack phase
+        @state = @state + delta
+
+        if @state >= 0
+          -- fall through to decay phase with remaining delta
+          delta = @state
+          @state = decay
+        else
+          @out\set 1 + @state / attack
+          return
+
+      if @state > 0
+        -- decay phase
+        @state = math.max 0, @state - delta
+        @out\set @state / decay
+
+    vis: => type: 'bar', bar: @.out!
 
 Constant.meta
   meta:
@@ -256,3 +353,5 @@ Constant.meta
     :ramp
     :tick
     :phase
+    :decay
+    :ad