Add audio_raw_stream_callback.c

examples/audio/audio_raw_stream_callback.c

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+/*******************************************************************************************
+ *
+ *   raylib [audio] example - raw stream callback
+ *
+ *   Example complexity rating: [★★★☆] 3/4
+ *
+ *   Example originally created with raylib 1.6, last time updated with raylib 4.2
+ *
+ *   Example created by Ramon Santamaria (@raysan5) and reviewed by James Hofmann (@triplefox)
+ *
+ *   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) 2015-2025 Ramon Santamaria (@raysan5) and James Hofmann (@triplefox)
+ *
+ ********************************************************************************************/
+
+#include "raylib.h"
+#include <math.h>
+
+#define BUFFER_SIZE 4096
+#define SAMPLE_RATE 44100
+
+// This example sends a sine wave to the audio device
+int sineFrequency = 440;
+int newSineFrequency = 440;
+int sineIndex = 0;
+double sineStartTime = 0.0;
+
+void AudioStreamCallback(void *framesOut, unsigned int frameCount)
+{
+    for (int i = 0; i < frameCount; i++)
+    {
+        int wavelength = SAMPLE_RATE/sineFrequency;
+        ((float *)framesOut)[i] = sin(2*PI*sineIndex/wavelength);
+
+        sineIndex++;
+
+        if (sineIndex >= wavelength)
+        {
+            sineFrequency = newSineFrequency;
+            sineIndex = 0;
+            sineStartTime = GetTime();
+        }
+    }
+}
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [audio] example - raw stream callback");
+    SetTargetFPS(30);
+
+    InitAudioDevice();
+
+    // Set the number of samples the stream will keep in memory at a time to BUFFER_SIZE
+    SetAudioStreamBufferSizeDefault(BUFFER_SIZE);
+
+    // Init raw audio stream (sample rate: 44100, sample size: 32bit-float, channels: 1-mono)
+    AudioStream stream = LoadAudioStream(SAMPLE_RATE, 32, 1);
+    float pan = 0.0f;
+    SetAudioStreamPan(stream, pan);
+    PlayAudioStream(stream);
+
+    // Configure it so AudioStreamCallback is called whenever stream is out of samples
+    SetAudioStreamCallback(stream, AudioStreamCallback);
+
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+
+        if (IsKeyDown(KEY_UP))
+        {
+            newSineFrequency += 10;
+
+            if (newSineFrequency > 12500)
+                newSineFrequency = 12500;
+        }
+
+        if (IsKeyDown(KEY_DOWN))
+        {
+            newSineFrequency -= 10;
+
+            if (newSineFrequency < 20)
+                newSineFrequency = 20;
+        }
+
+        if (IsKeyDown(KEY_LEFT))
+        {
+            pan -= 0.01f;
+            SetAudioStreamPan(stream, pan);
+
+            if (pan < -1.0f)
+                pan = -1.0f;
+        }
+
+        if (IsKeyDown(KEY_RIGHT))
+        {
+            pan += 0.01f;
+            SetAudioStreamPan(stream, pan);
+
+            if (pan > 1.0f)
+                pan = 1.0f;
+        }
+
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+        ClearBackground(RAYWHITE);
+
+        DrawText(TextFormat("sine frequency: %i", sineFrequency), screenWidth - 220, 10, 20, RED);
+        DrawText(TextFormat("pan: %.2f", pan), screenWidth - 220, 30, 20, RED);
+        DrawText("Up/down to change frequency", 10, 10, 20, DARKGRAY);
+        DrawText("Left/right to pan", 10, 30, 20, DARKGRAY);
+
+        int windowStart = (GetTime() - sineStartTime)*SAMPLE_RATE;
+        int windowSize = 0.1f*SAMPLE_RATE;
+        int wavelength = SAMPLE_RATE/sineFrequency;
+
+        // Draw a sine wave with the same frequency as the one being sent to the audio stream
+        for (int i = 0; i < screenWidth; i++) {
+            int t0 = windowStart + i*windowSize/screenWidth;
+            int t1 = windowStart + (i + 1)*windowSize/screenWidth;
+            Vector2 startPos = { i, 250 + 50*sin(2*PI*t0/wavelength) };
+            Vector2 endPos = { i + 1, 250 + 50*sin(2*PI*t1/wavelength) };
+            DrawLineV(startPos, endPos, RED);
+        }
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    UnloadAudioStream(stream);   // Close raw audio stream and delete buffers from RAM
+    CloseAudioDevice();         // Close audio device (music streaming is automatically stopped)
+
+    CloseWindow();              // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}