mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
90 lines
2.2 KiB
Go
90 lines
2.2 KiB
Go
// Copyright 2018 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package convert_test
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import (
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"io/ioutil"
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"math"
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"testing"
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"github.com/hajimehoshi/ebiten/audio"
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. "github.com/hajimehoshi/ebiten/audio/internal/convert"
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)
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func soundAt(timeInSecond float64) float64 {
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const freq = 220
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amp := []float64{1.0, 0.8, 0.6, 0.4, 0.2}
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v := 0.0
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for j := 0; j < len(amp); j++ {
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v += amp[j] * math.Sin(2.0*math.Pi*timeInSecond*freq*float64(j+1))
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}
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if v > 1 {
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v = 1
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}
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if v < -1 {
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v = -1
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}
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return v
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}
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func newSoundBytes(sampleRate int) []byte {
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b := make([]byte, sampleRate*4) // 1 second
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for i := 0; i < len(b)/4; i++ {
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v := soundAt(float64(i) / float64(sampleRate))
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v16 := int16(v * (1<<15 - 1))
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b[4*i] = byte(v16)
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b[4*i+1] = byte(v16 >> 8)
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b[4*i+2] = byte(v16)
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b[4*i+3] = byte(v16 >> 8)
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}
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return b
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}
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func TestResampling(t *testing.T) {
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cases := []struct {
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In int
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Out int
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}{
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{
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In: 44100,
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Out: 48000,
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},
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{
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In: 48000,
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Out: 44100,
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},
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}
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for _, c := range cases {
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inB := newSoundBytes(c.In)
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outS := NewResampling(audio.BytesReadSeekCloser(inB), int64(len(inB)), c.In, c.Out)
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gotB, err := ioutil.ReadAll(outS)
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if err != nil {
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t.Fatal(err)
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}
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wantB := newSoundBytes(c.Out)
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if len(gotB) != len(wantB) {
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t.Errorf("len(gotB) == %d but len(wantB) == %d", len(gotB), len(wantB))
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}
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for i := 0; i < len(gotB)/2; i++ {
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got := float64(int16(gotB[2*i])|(int16(gotB[2*i+1])<<8)) / (1<<15 - 1)
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want := float64(int16(wantB[2*i])|(int16(wantB[2*i+1])<<8)) / (1<<15 - 1)
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if math.Abs(got-want) > 0.025 {
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t.Errorf("sample rate: %d, index: %d: got: %f, want: %f", c.Out, i, got, want)
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}
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}
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}
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}
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