mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 21:32:20 +02:00
88 lines
1.9 KiB
Go
88 lines
1.9 KiB
Go
// Copyright 2015 Hajime Hoshi
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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 main
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import (
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"fmt"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/ebitenutil"
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"log"
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"math/rand"
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)
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const (
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screenWidth = 320
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screenHeight = 240
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)
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var frames = 0
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const (
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hzA = 440.0
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hzAS = 466.2
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hzB = 493.9
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hzC = 523.3
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hzCS = 554.4
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hzD = 587.3
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hzDS = 622.3
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hzE = 659.3
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hzF = 698.5
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hzFS = 740.0
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hzG = 784.0
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hzGS = 830.6
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)
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// TODO: Need API to get sample rate?
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const sampleRate = 44100
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func square(out []float32, hz float64, sequence float64) {
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length := int(sampleRate / hz)
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if length == 0 {
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panic("invalid hz")
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}
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for i := 0; i < len(out); i++ {
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a := float32(1.0)
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if i%length < int(float64(length)*sequence) {
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a = 0
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}
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out[i] = a
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}
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}
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func update(screen *ebiten.Image) error {
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defer func() {
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frames++
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}()
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const size = sampleRate / 60 // 3600 BPM
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notes := []float64{hzA, hzB, hzC, hzD, hzE, hzF, hzG, hzA * 2}
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if frames%30 == 0 {
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l := make([]float32, size*30)
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r := make([]float32, size*30)
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note := notes[rand.Intn(len(notes))]
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square(l, note, 0.5)
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square(r, note, 0.5)
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ebiten.AppendAudioBuffer(l, r)
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}
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ebitenutil.DebugPrint(screen, fmt.Sprintf("%0.2f", ebiten.CurrentFPS()))
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return nil
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}
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func main() {
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if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Rotate (Ebiten Demo)"); err != nil {
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log.Fatal(err)
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}
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}
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