refactor(oto): reuse temp buffers for repeated calls to convert buffer

oto/convertbuffer.go

@@ -1,29 +1,25 @@
 package oto
 
 import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
 	"math"
 )
 
 // FloatBufferTo16BitLE is a naive helper method to convert []float32 buffers to
-// 16-bit little-endian integer buffers.
-// TODO: optimize/refactor this, current is far from the best solution
-func FloatBufferTo16BitLE(buff []float32) ([]byte, error) {
-	var buf bytes.Buffer
-	for i, v := range buff {
+// 16-bit little-endian, but encoded in byte buffer
+//
+// Appends the encoded bytes into "to" slice, allowing you to preallocate the
+// capacity or just use nil
+func FloatBufferTo16BitLE(from []float32, to []byte) []byte {
+	for _, v := range from {
 		var uv int16
 		if v < -1.0 {
-			uv = -math.MaxInt16
+			uv = -math.MaxInt16 // we are a bit lazy: -1.0 is encoded as -32767, as this makes math easier, and -32768 is unused
 		} else if v > 1.0 {
 			uv = math.MaxInt16
 		} else {
 			uv = int16(v * math.MaxInt16)
 		}
-		if err := binary.Write(&buf, binary.LittleEndian, uv); err != nil {
-			return nil, fmt.Errorf("error converting buffer (@ %v, value %v) to bytes: %w", i, v, err)
-		}
+		to = append(to, byte(uv&255), byte(uv>>8))
 	}
-	return buf.Bytes(), nil
+	return to
 }