155 lines
4.2 KiB
Go
155 lines
4.2 KiB
Go
/*******************************************************************************************
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*
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* raylib [audio] example - Mixed audio processing
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*
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* Example originally created with raylib 4.2, last time updated with raylib 4.2
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*
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* Example contributed by hkc (@hatkidchan) and reviewed by Ramon Santamaria (@raysan5)
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2023 hkc (@hatkidchan)
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*
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********************************************************************************************/
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package main
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import (
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"fmt"
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"math"
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rl "github.com/gen2brain/raylib-go/raylib"
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)
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const (
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screenWidth = 800
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screenHeight = 450
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)
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var exponent float32 = 1.0 // Audio exponentiation value
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var averageVolume [400]float32 // Average volume history
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func main() {
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rl.InitWindow(screenWidth, screenHeight, "raylib [audio] example - processing mixed output")
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rl.InitAudioDevice() // Initialize audio device
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rl.AttachAudioMixedProcessor(ProcessAudio)
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music := rl.LoadMusicStream("country.mp3")
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sound := rl.LoadSound("coin.wav")
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rl.PlayMusicStream(music)
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rl.SetTargetFPS(60) // Set our game to run at 60 frames-per-second
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// Main game loop
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for !rl.WindowShouldClose() { // Detect window close button or ESC key
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rl.UpdateMusicStream(music) // Update music buffer with new stream data
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// Modify processing variables
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if rl.IsKeyPressed(rl.KeyLeft) {
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exponent -= 0.05
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}
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if rl.IsKeyPressed(rl.KeyRight) {
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exponent += 0.05
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}
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if rl.IsKeyPressed(rl.KeyDown) {
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exponent -= 0.25
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}
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if rl.IsKeyPressed(rl.KeyUp) {
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exponent += 0.25
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}
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// Make sure that exponent stays between 0.5 and 3
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exponent = clamp(exponent, 0.5, 3)
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if rl.IsKeyPressed(rl.KeySpace) {
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rl.PlaySound(sound)
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}
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// Draw
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rl.BeginDrawing()
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rl.ClearBackground(rl.RayWhite)
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rl.DrawText("MUSIC SHOULD BE PLAYING!", 255, 150, 20, rl.LightGray)
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rl.DrawText(fmt.Sprintf("EXPONENT = %.2f", exponent), 215, 180, 20, rl.LightGray)
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rl.DrawRectangle(199, 199, 402, 34, rl.LightGray)
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for i := int32(0); i < 400; i++ {
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rl.DrawLine(201+i, 232-int32(averageVolume[i]*32), 201+i, 232, rl.Maroon)
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}
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rl.DrawRectangleLines(199, 199, 402, 34, rl.Gray)
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rl.DrawText("PRESS SPACE TO PLAY OTHER SOUND", 200, 250, 20, rl.LightGray)
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rl.DrawText("USE LEFT AND RIGHT ARROWS TO ALTER DISTORTION", 140, 280, 20, rl.LightGray)
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rl.EndDrawing()
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}
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// De-Initialization
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rl.UnloadMusicStream(music) // Unload music stream buffers from RAM
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rl.DetachAudioMixedProcessor(ProcessAudio) // Disconnect audio processor
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rl.CloseAudioDevice() // Close audio device (music streaming is automatically stopped)
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rl.CloseWindow() // Close window and OpenGL context
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}
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// ProcessAudio is the audio processing function
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func ProcessAudio(buffer []float32, frames int) {
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var average float32 // Temporary average volume
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maxFrame := frames / 2
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// Each frame has 2 samples (left and right),
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// so we should loop `frames / 2` times
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for frame := 0; frame < maxFrame; frame++ {
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left := &buffer[frame*2+0] // Left channel
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right := &buffer[frame*2+1] // Right channel
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// Modify left and right channel samples with exponent
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*left = pow(abs(*left), exponent) * sgn(*left)
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*right = pow(abs(*right), exponent) * sgn(*right)
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// Accumulating average volume
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average += abs(*left) / float32(maxFrame)
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average += abs(*right) / float32(maxFrame)
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}
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// Shift average volume history buffer to the left
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for i := 0; i < 399; i++ {
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averageVolume[i] = averageVolume[i+1]
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}
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// Add the new average value
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averageVolume[399] = average
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}
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// Helper functions to make the code shorter
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// (using less type conversions)
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// (Golang: Please make the `math` package generic! This is ridiculous :-)
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func abs(value float32) float32 {
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return float32(math.Abs(float64(value)))
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}
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func pow(value, exponent float32) float32 {
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return float32(math.Pow(float64(value), float64(exponent)))
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}
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func sgn(value float32) float32 {
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if value < 0 {
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return -1
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} else if value > 0 {
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return 1
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}
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return 0
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}
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func clamp(value, min, max float32) float32 {
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if value < min {
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return min
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}
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if value > max {
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return max
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}
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return value
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}
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