Improves 0 timestamp

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.4] - 2021-12-15
+
+### Fixed
+
+- Makes `run` start at 0.0 seconds all the time, allowing for smoother starts of works. Additional optimizations can be done, like graph pre-rendering for the 0 time frame (not sure if this is in fact an optimization, could even be slower, but theoretically it would optimize things), but this sounds good enough on first blush to leave it as-is for the time being.
+
 ## [0.6.3] - 2021-12-15
 
 ### Fixed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "purescript-wags",
-  "version": "0.6.3",
+  "version": "0.6.4",
   "description": "Web Audio Graphs as a Stream",
   "scripts": {
     "build": "spago build",

src/WAGS/Run.purs

@@ -19,12 +19,13 @@ module WAGS.Run
 
 import Prelude
 
+import Control.Alt (alt)
 import Control.Comonad.Cofree (Cofree, head, tail)
 import Data.DateTime.Instant (Instant, unInstant)
 import Data.Foldable (for_)
 import Data.Int (floor, toNumber)
 import Data.List (List(..))
-import Data.Maybe (Maybe(..), isNothing)
+import Data.Maybe (Maybe(..), fromMaybe, isNothing)
 import Data.Newtype (class Newtype)
 import Data.Symbol (class IsSymbol)
 import Data.Time.Duration (Milliseconds)
@@ -166,7 +167,7 @@ run' :: forall analysersRL analysers analyserCallbacks analyserRefs trigger worl
 run' loop trigger inWorld engineInfo audioInfo scene =
   makeEvent \k -> do
     refsForAnalysers <- makeAnalyserRefs (Proxy :: _ analysersRL)
-    audioClockStart <- getAudioClockTime (contextFromSnapshot audioInfo)
+    audioClockStartRef <- Ref.new (Nothing :: Maybe Number)
     currentTimeoutCanceler <- Ref.new (pure unit :: Effect Unit)
     currentScene <- Ref.new scene
     currentEasingAlg <- Ref.new engineInfo.easingAlgorithm
@@ -195,7 +196,7 @@ run' loop trigger inWorld engineInfo audioInfo scene =
         cancelTimeout <- Ref.read currentTimeoutCanceler
         cancelTimeout
         runInternal
-          audioClockStart
+          audioClockStartRef
           ee
           newWorld
           currentTimeoutCanceler
@@ -211,7 +212,7 @@ run' loop trigger inWorld engineInfo audioInfo scene =
       unsubscribe
   where
   runInternal
-    :: Number
+    :: Ref.Ref (Maybe Number)
     -> { world :: world
        , trigger :: Maybe trigger
        , sysTime :: Milliseconds
@@ -228,12 +229,11 @@ run' loop trigger inWorld engineInfo audioInfo scene =
     -> { | analyserRefs }
     -> (Run res analysers -> Effect Unit)
     -> Effect Unit
-  runInternal audioClockStart fromEvents world' currentTimeoutCanceler currentEasingAlg currentScene ffiSnapshot analyserCallbacks analyserRefs reporter = do
+  runInternal audioClockStartRef fromEvents world' currentTimeoutCanceler currentEasingAlg currentScene ffiSnapshot analyserCallbacks analyserRefs reporter = do
     easingAlgNow <- Ref.read currentEasingAlg
     sceneNow <- Ref.read currentScene
-    let ctx = contextFromSnapshot ffiSnapshot
-    audioClockPriorToComputation <- getAudioClockTime ctx
     let
+      ctx = contextFromSnapshot ffiSnapshot
       -- this is how far in the future we are telling the
       -- algorithm to calculate with respect to the audio clock
       -- it is a bet:  we bet that the algorithm will finish
@@ -242,7 +242,11 @@ run' loop trigger inWorld engineInfo audioInfo scene =
 
       headroomInSeconds = (toNumber headroom) / 1000.0
 
-      time = (audioClockPriorToComputation - audioClockStart) + headroomInSeconds
+    audioClockPriorToComputation <- getAudioClockTime ctx
+    audioClockStart <- fromMaybe audioClockPriorToComputation
+     <$> Ref.modify (flip alt (Just audioClockPriorToComputation)) audioClockStartRef
+    let
+      time = audioClockPriorToComputation - audioClockStart
 
       fromScene =
         oneFrame sceneNow
@@ -264,7 +268,6 @@ run' loop trigger inWorld engineInfo audioInfo scene =
     renderAudio (map snd applied)
     let
       remainingTimeInSeconds = audioClockPriorToComputation + headroomInSeconds - audioClockAfterComputation
-
       remainingTime = floor $ 1000.0 * remainingTimeInSeconds
     Ref.write (tail easingAlgNow remainingTime) currentEasingAlg
     Ref.write
@@ -289,7 +292,7 @@ run' loop trigger inWorld engineInfo audioInfo scene =
           \{ world
           , sysTime
           } ->
-            runInternal audioClockStart
+            runInternal audioClockStartRef
               { world
               , sysTime
               , trigger: Nothing