copy audio_raw_stream.c to new file as-is

Author: meisei4

examples/Makefile

@@ -707,6 +707,7 @@ AUDIO = \
     audio/audio_module_playing \
     audio/audio_music_stream \
     audio/audio_raw_stream \
+    audio/audio_raw_stream_callback \
     audio/audio_sound_loading \
     audio/audio_sound_multi \
     audio/audio_sound_positioning \

examples/audio/audio_raw_stream_callback.c

@@ -0,0 +1,214 @@
+/*******************************************************************************************
+*
+*   raylib [audio] example - raw stream
+*
+*   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 <stdlib.h>         // Required for: malloc(), free()
+#include <math.h>           // Required for: sinf()
+#include <string.h>         // Required for: memcpy()
+
+#define MAX_SAMPLES               512
+#define MAX_SAMPLES_PER_UPDATE   4096
+
+// Cycles per second (hz)
+float frequency = 440.0f;
+
+// Audio frequency, for smoothing
+float audioFrequency = 440.0f;
+
+// Previous value, used to test if sine needs to be rewritten, and to smoothly modulate frequency
+float oldFrequency = 1.0f;
+
+// Index for audio rendering
+float sineIdx = 0.0f;
+
+// Audio input processing callback
+void AudioInputCallback(void *buffer, unsigned int frames)
+{
+    audioFrequency = frequency + (audioFrequency - frequency)*0.95f;
+
+    float incr = audioFrequency/44100.0f;
+    short *d = (short *)buffer;
+
+    for (unsigned int i = 0; i < frames; i++)
+    {
+        d[i] = (short)(32000.0f*sinf(2*PI*sineIdx));
+        sineIdx += incr;
+        if (sineIdx > 1.0f) sineIdx -= 1.0f;
+    }
+}
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [audio] example - raw stream");
+
+    InitAudioDevice();              // Initialize audio device
+
+    SetAudioStreamBufferSizeDefault(MAX_SAMPLES_PER_UPDATE);
+
+    // Init raw audio stream (sample rate: 44100, sample size: 16bit-short, channels: 1-mono)
+    AudioStream stream = LoadAudioStream(44100, 16, 1);
+
+    SetAudioStreamCallback(stream, AudioInputCallback);
+
+    // Buffer for the single cycle waveform we are synthesizing
+    short *data = (short *)malloc(sizeof(short)*MAX_SAMPLES);
+
+    // Frame buffer, describing the waveform when repeated over the course of a frame
+    short *writeBuf = (short *)malloc(sizeof(short)*MAX_SAMPLES_PER_UPDATE);
+
+    PlayAudioStream(stream);        // Start processing stream buffer (no data loaded currently)
+
+    // Position read in to determine next frequency
+    Vector2 mousePosition = { -100.0f, -100.0f };
+
+    /*
+    // Cycles per second (hz)
+    float frequency = 440.0f;
+
+    // Previous value, used to test if sine needs to be rewritten, and to smoothly modulate frequency
+    float oldFrequency = 1.0f;
+
+    // Cursor to read and copy the samples of the sine wave buffer
+    int readCursor = 0;
+    */
+
+    // Computed size in samples of the sine wave
+    int waveLength = 1;
+
+    Vector2 position = { 0, 0 };
+
+    SetTargetFPS(30);               // Set our game to run at 30 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        mousePosition = GetMousePosition();
+
+        if (IsMouseButtonDown(MOUSE_BUTTON_LEFT))
+        {
+            float fp = (float)(mousePosition.y);
+            frequency = 40.0f + (float)(fp);
+
+            float pan = (float)(mousePosition.x)/(float)screenWidth;
+            SetAudioStreamPan(stream, pan);
+        }
+
+        // Rewrite the sine wave
+        // Compute two cycles to allow the buffer padding, simplifying any modulation, resampling, etc.
+        if (frequency != oldFrequency)
+        {
+            // Compute wavelength. Limit size in both directions
+            //int oldWavelength = waveLength;
+            waveLength = (int)(22050/frequency);
+            if (waveLength > MAX_SAMPLES/2) waveLength = MAX_SAMPLES/2;
+            if (waveLength < 1) waveLength = 1;
+
+            // Write sine wave
+            for (int i = 0; i < waveLength*2; i++)
+            {
+                data[i] = (short)(sinf(((2*PI*(float)i/waveLength)))*32000);
+            }
+            // Make sure the rest of the line is flat
+            for (int j = waveLength*2; j < MAX_SAMPLES; j++)
+            {
+                data[j] = (short)0;
+            }
+
+            // Scale read cursor's position to minimize transition artifacts
+            //readCursor = (int)(readCursor*((float)waveLength/(float)oldWavelength));
+            oldFrequency = frequency;
+        }
+
+        /*
+        // Refill audio stream if required
+        if (IsAudioStreamProcessed(stream))
+        {
+            // Synthesize a buffer that is exactly the requested size
+            int writeCursor = 0;
+
+            while (writeCursor < MAX_SAMPLES_PER_UPDATE)
+            {
+                // Start by trying to write the whole chunk at once
+                int writeLength = MAX_SAMPLES_PER_UPDATE-writeCursor;
+
+                // Limit to the maximum readable size
+                int readLength = waveLength-readCursor;
+
+                if (writeLength > readLength) writeLength = readLength;
+
+                // Write the slice
+                memcpy(writeBuf + writeCursor, data + readCursor, writeLength*sizeof(short));
+
+                // Update cursors and loop audio
+                readCursor = (readCursor + writeLength) % waveLength;
+
+                writeCursor += writeLength;
+            }
+
+            // Copy finished frame to audio stream
+            UpdateAudioStream(stream, writeBuf, MAX_SAMPLES_PER_UPDATE);
+        }
+        */
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            DrawText(TextFormat("sine frequency: %i",(int)frequency), GetScreenWidth() - 220, 10, 20, RED);
+            DrawText("click mouse button to change frequency or pan", 10, 10, 20, DARKGRAY);
+
+            // Draw the current buffer state proportionate to the screen
+            for (int i = 0; i < screenWidth; i++)
+            {
+                position.x = (float)i;
+                position.y = 250 + 50*data[i*MAX_SAMPLES/screenWidth]/32000.0f;
+
+                DrawPixelV(position, RED);
+            }
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    free(data);                 // Unload sine wave data
+    free(writeBuf);             // Unload write buffer
+
+    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;
+}