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165 lines
6.1 KiB
165 lines
6.1 KiB
/*******************************************************************************************
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*
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* raylib [audio] example - Raw audio streaming
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*
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* NOTE: This example requires OpenAL Soft library installed
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*
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* This example has been created using raylib 1.6 (www.raylib.com)
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* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
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*
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* Copyright (c) 2015-2019 Ramon Santamaria (@raysan5) and James Hofmann (@triplefox)
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*
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********************************************************************************************/
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#include "raylib.h"
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#include <stdlib.h> // Required for: malloc(), free()
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#include <math.h> // Required for: sinf()
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#include <string.h> // Required for: memcpy()
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#define MAX_SAMPLES 512
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#define MAX_SAMPLES_PER_UPDATE 4096
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int main(void)
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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const int screenWidth = 800;
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const int screenHeight = 450;
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InitWindow(screenWidth, screenHeight, "raylib [audio] example - raw audio streaming");
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InitAudioDevice(); // Initialize audio device
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// Init raw audio stream (sample rate: 22050, sample size: 16bit-short, channels: 1-mono)
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AudioStream stream = InitAudioStream(22050, 16, 1);
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// Buffer for the single cycle waveform we are synthesizing
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short *data = (short *)malloc(sizeof(short)*MAX_SAMPLES);
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// Frame buffer, describing the waveform when repeated over the course of a frame
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short *writeBuf = (short *)malloc(sizeof(short)*MAX_SAMPLES_PER_UPDATE);
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PlayAudioStream(stream); // Start processing stream buffer (no data loaded currently)
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// Position read in to determine next frequency
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Vector2 mousePosition = { -100.0f, -100.0f };
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// Cycles per second (hz)
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float frequency = 440.0f;
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// Previous value, used to test if sine needs to be rewritten, and to smoothly modulate frequency
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float oldFrequency = 1.0f;
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// Cursor to read and copy the samples of the sine wave buffer
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int readCursor = 0;
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// Computed size in samples of the sine wave
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int waveLength = 1;
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Vector2 position = { 0, 0 };
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SetTargetFPS(30); // Set our game to run at 30 frames-per-second
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//--------------------------------------------------------------------------------------
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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// Update
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//----------------------------------------------------------------------------------
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// Sample mouse input.
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mousePosition = GetMousePosition();
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if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
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{
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float fp = (float)(mousePosition.y);
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frequency = 40.0f + (float)(fp);
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}
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// Rewrite the sine wave.
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// Compute two cycles to allow the buffer padding, simplifying any modulation, resampling, etc.
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if (frequency != oldFrequency)
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{
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// Compute wavelength. Limit size in both directions.
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int oldWavelength = waveLength;
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waveLength = (int)(22050/frequency);
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if (waveLength > MAX_SAMPLES/2) waveLength = MAX_SAMPLES/2;
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if (waveLength < 1) waveLength = 1;
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// Write sine wave.
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for (int i = 0; i < waveLength*2; i++)
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{
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data[i] = (short)(sinf(((2*PI*(float)i/waveLength)))*32000);
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}
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// Scale read cursor's position to minimize transition artifacts
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readCursor = (int)(readCursor * ((float)waveLength / (float)oldWavelength));
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oldFrequency = frequency;
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}
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// Refill audio stream if required
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if (IsAudioBufferProcessed(stream))
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{
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// Synthesize a buffer that is exactly the requested size
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int writeCursor = 0;
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while (writeCursor < MAX_SAMPLES_PER_UPDATE)
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{
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// Start by trying to write the whole chunk at once
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int writeLength = MAX_SAMPLES_PER_UPDATE-writeCursor;
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// Limit to the maximum readable size
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int readLength = waveLength-readCursor;
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if (writeLength > readLength) writeLength = readLength;
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// Write the slice
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memcpy(writeBuf + writeCursor, data + readCursor, writeLength*sizeof(short));
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// Update cursors and loop audio
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readCursor = (readCursor + writeLength) % waveLength;
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writeCursor += writeLength;
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}
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// Copy finished frame to audio stream
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UpdateAudioStream(stream, writeBuf, MAX_SAMPLES_PER_UPDATE);
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}
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(RAYWHITE);
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DrawText(FormatText("sine frequency: %i",(int)frequency), GetScreenWidth() - 220, 10, 20, RED);
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DrawText("click mouse button to change frequency", 10, 10, 20, DARKGRAY);
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// Draw the current buffer state proportionate to the screen
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for (int i = 0; i < screenWidth; i++)
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{
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position.x = i;
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position.y = 250 + 50*data[i*MAX_SAMPLES/screenWidth]/32000;
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DrawPixelV(position, RED);
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}
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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// De-Initialization
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//--------------------------------------------------------------------------------------
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free(data); // Unload sine wave data
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free(writeBuf); // Unload write buffer
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CloseAudioStream(stream); // Close raw audio stream and delete buffers from RAM
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CloseAudioDevice(); // Close audio device (music streaming is automatically stopped)
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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}
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