possible to disable wasm render on start

song.go

@@ -11,11 +11,12 @@ import (
 // playback speed, but this could be changed to a floating point in future if
 // finer adjustments are necessary.
 type Song struct {
-	BPM                 int
-	RowsPerBeat         int
-	Score               Score
-	Patch               Patch
-	CreateEmptyPatterns bool
+	BPM                      int
+	RowsPerBeat              int
+	Score                    Score
+	Patch                    Patch
+	CreateEmptyPatterns      bool
+	WasmDisableRenderOnStart bool
 }
 
 // Copy makes a deep copy of a Score.

templates/wasm/player.wat

@@ -880,7 +880,9 @@
 (export "render_128_samples" (func $render_128_samples))
 (export "update_voices" (func $su_update_voices))
 
+{{- if  .RenderOnStart }}
 (start $render) ;; we run render automagically when the module is instantiated
+{{- end}}
 
 (func $render (param)
 {{- if  .Output16Bit }} (local $channel i32) {{- end }}

tests/test_diff_wasm_x86.yml

@@ -1,6 +1,7 @@
 bpm: 120
 rowsperbeat: 4
 createemptypatterns: true
+wasmdisablerenderonstart: false
 score:
   length: 1
   rowsperpattern: 16

vm/compiler/compiler.go

@@ -126,7 +126,8 @@ func (com *Compiler) Song(song *sointu.Song) (map[string]string, error) {
 				PatternLength  int
 				SequenceLength int
 				Hold           int
-			}{compilerMacros, featureSetMacros, wasmMacros, songMacros, encodedPatch, patterns, sequences, len(patterns[0]), len(sequences[0]), 1}
+				RenderOnStart  bool
+			}{compilerMacros, featureSetMacros, wasmMacros, songMacros, encodedPatch, patterns, sequences, len(patterns[0]), len(sequences[0]), 1, !song.WasmDisableRenderOnStart}
 			populatedTemplate, extension, err = com.compile(templateName, &data)
 		}
 		if err != nil {