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288 lines
11 KiB
288 lines
11 KiB
/*******************************************************************************************
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*
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* raylib [audio] example - fft spectrum visualizer
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*
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* Example complexity rating: [★★★☆] 3/4
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*
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* Example originally created with raylib 6.0, last time updated with raylib 5.6-dev
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*
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* Inspired by Inigo Quilez's https://www.shadertoy.com/
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* Resources/specification: https://gist.github.com/soulthreads/2efe50da4be1fb5f7ab60ff14ca434b8
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*
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* Example created by created by IANN (@meisei4) 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) 2025 IANN (@meisei4)
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*
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********************************************************************************************/
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#include "raylib.h"
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#include "raymath.h"
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#if defined(PLATFORM_DESKTOP)
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#define GLSL_VERSION 330
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#else // PLATFORM_ANDROID, PLATFORM_WEB
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#define GLSL_VERSION 100
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#endif
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#define MONO 1
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#define SAMPLE_RATE 44100
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#define SAMPLE_RATE_F 44100.0f
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#define FFT_WINDOW_SIZE 1024
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#define BUFFER_SIZE 512
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#define PER_SAMPLE_BIT_DEPTH 16
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#define AUDIO_STREAM_RING_BUFFER_SIZE (FFT_WINDOW_SIZE*2)
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#define EFFECTIVE_SAMPLE_RATE (SAMPLE_RATE_F*0.5f)
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#define WINDOW_TIME ((double)FFT_WINDOW_SIZE/(double)EFFECTIVE_SAMPLE_RATE)
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#define FFT_HISTORICAL_SMOOTHING_DUR 2.0f
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#define MIN_DECIBELS (-100.0f) // https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/minDecibels
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#define MAX_DECIBELS (-30.0f) // https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/maxDecibels
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#define INVERSE_DECIBEL_RANGE (1.0f/(MAX_DECIBELS - MIN_DECIBELS))
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#define DB_TO_LINEAR_SCALE (20.0f/2.302585092994046f)
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#define SMOOTHING_TIME_CONSTANT 0.8f // https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/smoothingTimeConstant
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#define TEXTURE_HEIGHT 1
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#define FFT_ROW 0
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#define UNUSED_CHANNEL 0.0f
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typedef struct FFTComplex { float real, imaginary; } FFTComplex;
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typedef struct FFTData {
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FFTComplex *spectrum;
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FFTComplex *workBuffer;
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float *prevMagnitudes;
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float (*fftHistory)[BUFFER_SIZE];
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int fftHistoryLen;
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int historyPos;
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double lastFftTime;
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float tapbackPos;
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} FFTData;
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static void CaptureFrame(FFTData *fftData, const float *audioSamples);
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static void RenderFrame(const FFTData *fftData, Image *fftImage);
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static void CooleyTukeyFFTSlow(FFTComplex *spectrum, int n);
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//------------------------------------------------------------------------------------
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// Program main entry point
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//------------------------------------------------------------------------------------
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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 - fft spectrum visualizer");
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Image fftImage = GenImageColor(BUFFER_SIZE, TEXTURE_HEIGHT, WHITE);
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Texture2D fftTexture = LoadTextureFromImage(fftImage);
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RenderTexture2D bufferA = LoadRenderTexture(screenWidth, screenHeight);
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Vector2 iResolution = { (float)screenWidth, (float)screenHeight };
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Shader shader = LoadShader(0, TextFormat("resources/shaders/glsl%i/fft.fs", GLSL_VERSION));
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int iResolutionLocation = GetShaderLocation(shader, "iResolution");
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int iChannel0Location = GetShaderLocation(shader, "iChannel0");
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SetShaderValue(shader, iResolutionLocation, &iResolution, SHADER_UNIFORM_VEC2);
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SetShaderValueTexture(shader, iChannel0Location, fftTexture);
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InitAudioDevice();
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SetAudioStreamBufferSizeDefault(AUDIO_STREAM_RING_BUFFER_SIZE);
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// WARNING: Memory out-of-bounds on PLATFORM_WEB
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Wave wav = LoadWave("resources/country.mp3");
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WaveFormat(&wav, SAMPLE_RATE, PER_SAMPLE_BIT_DEPTH, MONO);
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AudioStream audioStream = LoadAudioStream(SAMPLE_RATE, PER_SAMPLE_BIT_DEPTH, MONO);
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PlayAudioStream(audioStream);
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int fftHistoryLen = (int)ceilf(FFT_HISTORICAL_SMOOTHING_DUR/WINDOW_TIME) + 1;
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FFTData fft = {
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.spectrum = RL_CALLOC(sizeof(FFTComplex), FFT_WINDOW_SIZE),
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.workBuffer = RL_CALLOC(sizeof(FFTComplex), FFT_WINDOW_SIZE),
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.prevMagnitudes = RL_CALLOC(BUFFER_SIZE, sizeof(float)),
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.fftHistory = RL_CALLOC(fftHistoryLen, sizeof(float[BUFFER_SIZE])),
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.fftHistoryLen = fftHistoryLen,
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.historyPos = 0,
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.lastFftTime = 0.0,
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.tapbackPos = 0.01f
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};
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size_t wavCursor = 0;
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const short *wavPCM16 = wav.data;
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short chunkSamples[AUDIO_STREAM_RING_BUFFER_SIZE] = { 0 };
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float audioSamples[FFT_WINDOW_SIZE] = { 0 };
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SetTargetFPS(60);
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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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while (IsAudioStreamProcessed(audioStream))
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{
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for (int i = 0; i < AUDIO_STREAM_RING_BUFFER_SIZE; i++)
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{
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int left = (wav.channels == 2)? wavPCM16[wavCursor*2 + 0] : wavPCM16[wavCursor];
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int right = (wav.channels == 2)? wavPCM16[wavCursor*2 + 1] : left;
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chunkSamples[i] = (short)((left + right)/2);
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if (++wavCursor >= wav.frameCount) wavCursor = 0;
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}
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UpdateAudioStream(audioStream, chunkSamples, AUDIO_STREAM_RING_BUFFER_SIZE);
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for (int i = 0; i < FFT_WINDOW_SIZE; i++) audioSamples[i] = (chunkSamples[i*2] + chunkSamples[i*2 + 1])*0.5f/32767.0f;
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}
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CaptureFrame(&fft, audioSamples);
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RenderFrame(&fft, &fftImage);
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UpdateTexture(fftTexture, fftImage.data);
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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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BeginShaderMode(shader);
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SetShaderValueTexture(shader, iChannel0Location, fftTexture);
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DrawTextureRec(bufferA.texture,
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(Rectangle){ 0, 0, (float)screenWidth, (float)-screenHeight },
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(Vector2){ 0, 0 }, WHITE);
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EndShaderMode();
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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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UnloadShader(shader);
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UnloadRenderTexture(bufferA);
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UnloadTexture(fftTexture);
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UnloadImage(fftImage);
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UnloadAudioStream(audioStream);
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UnloadWave(wav);
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CloseAudioDevice();
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RL_FREE(fft.spectrum);
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RL_FREE(fft.workBuffer);
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RL_FREE(fft.prevMagnitudes);
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RL_FREE(fft.fftHistory);
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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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// Cooley–Tukey FFT https://en.wikipedia.org/wiki/Cooley%E2%80%93Tukey_FFT_algorithm#Data_reordering,_bit_reversal,_and_in-place_algorithms
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static void CooleyTukeyFFTSlow(FFTComplex *spectrum, int n)
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{
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int j = 0;
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for (int i = 1; i < n - 1; i++)
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{
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int bit = n >> 1;
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while (j >= bit)
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{
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j -= bit;
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bit >>= 1;
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}
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j += bit;
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if (i < j)
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{
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FFTComplex temp = spectrum[i];
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spectrum[i] = spectrum[j];
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spectrum[j] = temp;
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}
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}
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for (int len = 2; len <= n; len <<= 1)
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{
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float angle = -2.0f*PI/len;
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FFTComplex twiddleUnit = { cosf(angle), sinf(angle) };
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for (int i = 0; i < n; i += len)
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{
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FFTComplex twiddleCurrent = { 1.0f, 0.0f };
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for (int j = 0; j < len/2; j++)
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{
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FFTComplex even = spectrum[i + j];
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FFTComplex odd = spectrum[i + j + len/2];
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FFTComplex twiddledOdd = {
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odd.real*twiddleCurrent.real - odd.imaginary*twiddleCurrent.imaginary,
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odd.real*twiddleCurrent.imaginary + odd.imaginary*twiddleCurrent.real
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};
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spectrum[i + j].real = even.real + twiddledOdd.real;
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spectrum[i + j].imaginary = even.imaginary + twiddledOdd.imaginary;
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spectrum[i + j + len/2].real = even.real - twiddledOdd.real;
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spectrum[i + j + len/2].imaginary = even.imaginary - twiddledOdd.imaginary;
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float twiddleRealNext = twiddleCurrent.real*twiddleUnit.real - twiddleCurrent.imaginary*twiddleUnit.imaginary;
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twiddleCurrent.imaginary = twiddleCurrent.real*twiddleUnit.imaginary + twiddleCurrent.imaginary*twiddleUnit.real;
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twiddleCurrent.real = twiddleRealNext;
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}
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}
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}
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}
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static void CaptureFrame(FFTData *fftData, const float *audioSamples)
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{
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for (int i = 0; i < FFT_WINDOW_SIZE; i++)
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{
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float x = (2.0f*PI*i)/(FFT_WINDOW_SIZE - 1.0f);
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float blackmanWeight = 0.42f - 0.5f*cosf(x) + 0.08f*cosf(2.0f*x); // https://en.wikipedia.org/wiki/Window_function#Blackman_window
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fftData->workBuffer[i].real = audioSamples[i]*blackmanWeight;
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fftData->workBuffer[i].imaginary = 0.0f;
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}
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CooleyTukeyFFTSlow(fftData->workBuffer, FFT_WINDOW_SIZE);
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memcpy(fftData->spectrum, fftData->workBuffer, sizeof(FFTComplex)*FFT_WINDOW_SIZE);
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float smoothedSpectrum[BUFFER_SIZE];
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for (int bin = 0; bin < BUFFER_SIZE; bin++)
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{
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float re = fftData->workBuffer[bin].real;
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float im = fftData->workBuffer[bin].imaginary;
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float linearMagnitude = sqrtf(re*re + im*im)/FFT_WINDOW_SIZE;
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float smoothedMagnitude = SMOOTHING_TIME_CONSTANT*fftData->prevMagnitudes[bin] + (1.0f - SMOOTHING_TIME_CONSTANT)*linearMagnitude;
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fftData->prevMagnitudes[bin] = smoothedMagnitude;
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float db = logf(fmaxf(smoothedMagnitude, 1e-40f))*DB_TO_LINEAR_SCALE;
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float normalized = (db - MIN_DECIBELS)*INVERSE_DECIBEL_RANGE;
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smoothedSpectrum[bin] = Clamp(normalized, 0.0f, 1.0f);
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}
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fftData->lastFftTime = GetTime();
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memcpy(fftData->fftHistory[fftData->historyPos], smoothedSpectrum, sizeof(smoothedSpectrum));
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fftData->historyPos = (fftData->historyPos + 1) % fftData->fftHistoryLen;
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}
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static void RenderFrame(const FFTData *fftData, Image *fftImage)
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{
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double framesSinceTapback = floor(fftData->tapbackPos/WINDOW_TIME);
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framesSinceTapback = Clamp(framesSinceTapback, 0.0, fftData->fftHistoryLen - 1);
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int historyPosition = (fftData->historyPos - 1 - (int)framesSinceTapback) % fftData->fftHistoryLen;
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if (historyPosition < 0)
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historyPosition += fftData->fftHistoryLen;
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const float *amplitude = fftData->fftHistory[historyPosition];
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for (int bin = 0; bin < BUFFER_SIZE; bin++) {
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ImageDrawPixel(fftImage, bin, FFT_ROW, ColorFromNormalized((Vector4){ amplitude[bin], UNUSED_CHANNEL, UNUSED_CHANNEL, UNUSED_CHANNEL }));
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}
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}
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