mixed processor
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Is it the same as C?
- Desktop:builds The Zig version builds, but it is not compared with C, because the C example does not give the same frame twice: self-nondeterministic under CPU load (C vs C 0/6 under load, passes idle): volume history drawn from the audio thread.
- Browser:not checked yet The browser comparison does not cover this example yet.
//! raylib [audio] example - mixed processor
//!
//! Zig-API translation of examples/audio/audio_mixed_processor.c (raylib 6.2).
//! Example contributed by hkc (@hatkidchan) and reviewed by Ramon Santamaria (@raysan5)
//! Example licensed under an unmodified zlib/libpng license.
//! Copyright (c) 2023-2025 hkc (@hatkidchan)
const std = @import("std");
const rl = @import("raylib");
var exponent: f32 = 1.0; // Audio exponentiation value
var average_volume: [400]f32 = @splat(0.0); // Average volume history
/// Audio processing function: runs on the audio thread for the whole mix.
fn processAudio(buffer: ?*anyopaque, frames: c_uint) callconv(.c) void {
// Samples internally stored as <float>s, interleaved stereo
const samples: [*]f32 = @ptrCast(@alignCast(buffer.?));
const frame_count: f32 = @floatFromInt(frames);
var average: f32 = 0.0; // Temporary average volume
for (samples[0 .. frames * 2]) |*sample| {
const sign: f32 = if (sample.* < 0.0) -1.0 else 1.0;
sample.* = std.math.pow(f32, @abs(sample.*), exponent) * sign;
average += @abs(sample.*) / frame_count; // accumulating average volume
}
// Moving history to the left
std.mem.copyForwards(f32, average_volume[0..399], average_volume[1..]);
average_volume[399] = average; // Adding last average value
}
pub fn main() !void {
// Initialization
const screen_width = 800;
const screen_height = 450;
rl.initWindow(screen_width, screen_height, "raylib [audio] example - mixed processor");
defer rl.closeWindow(); // Close window and OpenGL context
rl.initAudioDevice(); // Initialize audio device
defer rl.closeAudioDevice(); // Close audio device (music streaming is automatically stopped)
rl.attachAudioMixedProcessor(processAudio);
defer rl.detachAudioMixedProcessor(processAudio); // Disconnect audio processor
const music = try rl.loadMusicStream("resources/country.mp3");
defer rl.unloadMusicStream(music); // Unload music stream buffers from RAM
const sound = try rl.loadSound("resources/coin.wav");
defer rl.unloadSound(sound);
rl.playMusicStream(music);
rl.setTargetFPS(60); // Set our game to run at 60 frames-per-second
// Main game loop
while (!rl.windowShouldClose()) { // Detect window close button or ESC key
// Update
rl.updateMusicStream(music); // Update music buffer with new stream data
// Modify processing variables
if (rl.isKeyPressed(.left)) exponent -= 0.05;
if (rl.isKeyPressed(.right)) exponent += 0.05;
if (exponent <= 0.5) exponent = 0.5;
if (exponent >= 3.0) exponent = 3.0;
if (rl.isKeyPressed(.space)) rl.playSound(sound);
// Draw
rl.beginDrawing();
defer rl.endDrawing();
rl.clearBackground(.ray_white);
rl.drawText("MUSIC SHOULD BE PLAYING!", 255, 150, 20, .light_gray);
rl.drawText(rl.textFormat("EXPONENT = {d:.2}", .{exponent}), 215, 180, 20, .light_gray);
rl.drawRectangle(199, 199, 402, 34, .light_gray);
for (average_volume, 0..) |volume, i| {
const x = 201 + @as(i32, @intCast(i));
rl.drawLine(x, 232 - @as(i32, @intFromFloat(volume * 32)), x, 232, .maroon);
}
rl.drawRectangleLines(199, 199, 402, 34, .gray);
rl.drawText("PRESS SPACE TO PLAY OTHER SOUND", 200, 250, 20, .light_gray);
rl.drawText("USE LEFT AND RIGHT ARROWS TO ALTER DISTORTION", 140, 280, 20, .light_gray);
}
}/*******************************************************************************************
*
* raylib [audio] example - mixed processor
*
* Example complexity rating: [★★★★] 4/4
*
* Example originally created with raylib 4.2, last time updated with raylib 4.2
*
* Example contributed by hkc (@hatkidchan) and reviewed by Ramon Santamaria (@raysan5)
*
* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
* BSD-like license that allows static linking with closed source software
*
* Copyright (c) 2023-2025 hkc (@hatkidchan)
*
********************************************************************************************/
#include "raylib.h"
#include <math.h>
static float exponent = 1.0f; // Audio exponentiation value
static float averageVolume[400] = { 0.0f }; // Average volume history
//------------------------------------------------------------------------------------
// Audio processing function
//------------------------------------------------------------------------------------
void ProcessAudio(void *buffer, unsigned int frames)
{
float *samples = (float *)buffer; // Samples internally stored as <float>s
float average = 0.0f; // Temporary average volume
for (unsigned int frame = 0; frame < frames; frame++)
{
float *left = &samples[frame*2 + 0], *right = &samples[frame*2 + 1];
*left = powf(fabsf(*left), exponent)*( (*left < 0.0f)? -1.0f : 1.0f );
*right = powf(fabsf(*right), exponent)*( (*right < 0.0f)? -1.0f : 1.0f );
average += fabsf(*left)/frames; // accumulating average volume
average += fabsf(*right)/frames;
}
// Moving history to the left
for (int i = 0; i < 399; i++) averageVolume[i] = averageVolume[i + 1];
averageVolume[399] = average; // Adding last average value
}
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [audio] example - mixed processor");
InitAudioDevice(); // Initialize audio device
AttachAudioMixedProcessor(ProcessAudio);
Music music = LoadMusicStream("resources/country.mp3");
Sound sound = LoadSound("resources/coin.wav");
PlayMusicStream(music);
SetTargetFPS(60); // Set our game to run at 60 frames-per-second
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Update
//----------------------------------------------------------------------------------
UpdateMusicStream(music); // Update music buffer with new stream data
// Modify processing variables
//----------------------------------------------------------------------------------
if (IsKeyPressed(KEY_LEFT)) exponent -= 0.05f;
if (IsKeyPressed(KEY_RIGHT)) exponent += 0.05f;
if (exponent <= 0.5f) exponent = 0.5f;
if (exponent >= 3.0f) exponent = 3.0f;
if (IsKeyPressed(KEY_SPACE)) PlaySound(sound);
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
DrawText("MUSIC SHOULD BE PLAYING!", 255, 150, 20, LIGHTGRAY);
DrawText(TextFormat("EXPONENT = %.2f", exponent), 215, 180, 20, LIGHTGRAY);
DrawRectangle(199, 199, 402, 34, LIGHTGRAY);
for (int i = 0; i < 400; i++)
{
DrawLine(201 + i, 232 - (int)(averageVolume[i]*32), 201 + i, 232, MAROON);
}
DrawRectangleLines(199, 199, 402, 34, GRAY);
DrawText("PRESS SPACE TO PLAY OTHER SOUND", 200, 250, 20, LIGHTGRAY);
DrawText("USE LEFT AND RIGHT ARROWS TO ALTER DISTORTION", 140, 280, 20, LIGHTGRAY);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadMusicStream(music); // Unload music stream buffers from RAM
UnloadSound(sound);
DetachAudioMixedProcessor(ProcessAudio); // Disconnect audio processor
CloseAudioDevice(); // Close audio device (music streaming is automatically stopped)
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}From raylib 6.2. The original on GitHub.