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fix(asm/wasm): oscillator phase was causing rounding errors once large enough

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gopher had fixed this, but we foolishly removed it. reintroducing fix, although this could be optional only for those who really care. ultimate size optimizers could still want to get rid of it.
This commit is contained in:
Veikko Sariola
2020-12-30 21:19:27 +02:00
parent 7974f0ff82
commit c02c5c3c3d
47 changed files with 43 additions and 25 deletions
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47
templates/wasm/sources.wat
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@ -121,27 +121,34 @@
{{- end}}
(f32.store ;; update phase
(global.get $WRK)
;; Transpose calculation starts
(f32.div
(call $inputSigned (i32.const {{.InputNumber "oscillator" "transpose"}}))
(f32.const 0.015625)
) ;; scale back to 0 - 128
(f32.add (local.get $detune)) ;; add detune. detune is -1 to 1 so can detune a full note up or down at max
(f32.add (select
(f32.const 0)
(f32.convert_i32_u (i32.load (global.get $voice)))
(i32.and (local.get $flags) (i32.const 0x8))
)) ;; if lfo is not enabled, add the note number to it
(f32.mul (f32.const 0.0833333)) ;; /12, in full octaves
(call $pow2)
(f32.mul (select
(f32.const 0.000038) ;; pretty random scaling constant to get LFOs into reasonable range. Historical reasons, goes all the way back to 4klang
(f32.const 0.000092696138) ;; scaling constant to get middle-C to where it should be
(i32.and (local.get $flags) (i32.const 0x8))
))
(f32.add (f32.load (global.get $WRK))) ;; add the current phase of the oscillator
(local.tee $phase
(f32.sub
(local.tee $phase
;; Transpose calculation starts
(f32.div
(call $inputSigned (i32.const {{.InputNumber "oscillator" "transpose"}}))
(f32.const 0.015625)
) ;; scale back to 0 - 128
(f32.add (local.get $detune)) ;; add detune. detune is -1 to 1 so can detune a full note up or down at max
(f32.add (select
(f32.const 0)
(f32.convert_i32_u (i32.load (global.get $voice)))
(i32.and (local.get $flags) (i32.const 0x8))
)) ;; if lfo is not enabled, add the note number to it
(f32.mul (f32.const 0.0833333)) ;; /12, in full octaves
(call $pow2)
(f32.mul (select
(f32.const 0.000038) ;; pretty random scaling constant to get LFOs into reasonable range. Historical reasons, goes all the way back to 4klang
(f32.const 0.000092696138) ;; scaling constant to get middle-C to where it should be
(i32.and (local.get $flags) (i32.const 0x8))
))
(f32.add (f32.load (global.get $WRK))) ;; add the current phase of the oscillator
)
(f32.floor (local.get $phase))
)
)
)
(f32.add (f32.load (global.get $WRK)) (call $input (i32.const {{.InputNumber "oscillator" "phase"}})))
(f32.add (local.get $phase) (call $input (i32.const {{.InputNumber "oscillator" "phase"}})))
(local.set $phase (f32.sub (local.tee $phase) (f32.floor (local.get $phase)))) ;; phase = phase mod 1.0
(local.set $color (call $input (i32.const {{.InputNumber "oscillator" "color"}})))
{{- if .SupportsParamValue "oscillator" "type" .Sine}}