Topics

1

Audio / Does SFML Audio support float format Stream?

« on: January 10, 2019, 04:20:19 pm »

Give a quick look at source code,seems there is only int16(short) format,is it possible to use stream format like SDL2 does,fill in some struct and choose which format to use for audiocallback?

Right now I want to add reverb to audio like music or sound.I have get some reverb work on SDL2.
Base on float format[-1, +1],it is possible to convert from float to short,but could be a lot of work to do.
And I may add more audio effect like filter, compressor and so on.And they are all float format.
If I manually do these, time will be wasted meaninglessly.

And one more question,let's say I solve this format problem.Does SFML Audio have some ability to modify to final master audio out?Let's say I want to add reverb to all sound,but I don't want to apply to each of them,I just want to add reverb to the final master audio data,is it possible to do so?

2

Audio / How to usse Music::setLoopPoints

« on: January 08, 2019, 05:19:38 am »

Got trouble using this function.

This function requires TimeSpan,and TimeSpan requires Time.

And Time can't pass number direct into it.

Like float start = 1.807;
float loop = 3.371;

So how can I pass time to it?Any example?

3

Audio / Simple Real-time Audio Synthesizer with SFML2 Audio(Solved by myself)

« on: December 16, 2018, 11:15:26 am »

I have read this tutorial.

https://github.com/SFML/SFML/wiki/Tutorial:-Play-Sine-Wave

This is good if I can change the sound buffer tone real time.

Means if I press some key,then I will change the sine wave buffer to other pitch or completely change sine wave to saw or square wave or noise.

And I need to play an editable buffer and the buffer will play endlessly,or loop I guess.

========================================

OK.After a few days work,finally figure it out.

I will paste the code here in case someone may need it.

This is a Simple Real-time Audio Synthesizer which can generate tones on the fly.

I'm using Win7 VS2017 SFML2.5.1.And I only tested this on my computer.Not sure if it is 100% work for others.

Use Keys QWERT ... or ZXCVB ... just below Keys 12345 will trigger the notes,similar to FL Studio Keys.

Code is not optimized, but should be easy enough to understand how to fill audio callback real-time with SFML Audio.

#include <string>
#include <vector>

#include <SFML/Audio.hpp>
#include <SFML/Graphics.hpp>

using namespace std;

int ScreenWidth = 800;
int ScreenHeight = 600;

#define MAXVOL (0.22*32768)
#define DECAY (MAXVOL/4000)

#define KEYS 32
#define M_PI 3.14159265358979323846

float vol[KEYS] = { 0 };
float phase[KEYS] = { 0 };

int sampleRate = 44100;
int numChannel = 2;

int audioBufSize = 2048;

int octave = 0;

//0 sin
//1 triangle
//2 saw
//3 square
//4 white noise
int waveShapeType = 0;

class ShapeMode
{
public:
        static int const sine = 0;
        static int const triangle = 1;
        static int const saw = 2;
        static int const square = 3;
        static int const whiteNoise = 4;
};

sf::RenderWindow window;

string titleStr = "";
string noteStr = "0";
string octStr = "0";
string waveShapeStr = "0";

void UpdateAllString()
{
        titleStr = "waveShape: " + waveShapeStr + ", octave: " + octStr + ", note: " + noteStr;
        window.setTitle(titleStr);
}

const double PI2 = M_PI * 2;

float baseAFreq = 440;

bool keyBuf[sf::Keyboard::Key::KeyCount] = { false };
bool keyBuf_last[sf::Keyboard::Key::KeyCount] = { false };

int keymap[]{
        sf::Keyboard::Key::Z,
        sf::Keyboard::Key::S,
        sf::Keyboard::Key::X,
        sf::Keyboard::Key::D,
        sf::Keyboard::Key::C,
        sf::Keyboard::Key::V,
        sf::Keyboard::Key::G,
        sf::Keyboard::Key::B,
        sf::Keyboard::Key::H,
        sf::Keyboard::Key::N,
        sf::Keyboard::Key::J,
        sf::Keyboard::Key::M,
        sf::Keyboard::Key::Q,
        sf::Keyboard::Key::Num2,
        sf::Keyboard::Key::W,
        sf::Keyboard::Key::Num3,
        sf::Keyboard::Key::E,
        sf::Keyboard::Key::R,
        sf::Keyboard::Key::Num5,
        sf::Keyboard::Key::T,
        sf::Keyboard::Key::Num6,
        sf::Keyboard::Key::Y,
        sf::Keyboard::Key::Num7,
        sf::Keyboard::Key::U,
        sf::Keyboard::Key::I,
        sf::Keyboard::Key::Num9,
        sf::Keyboard::Key::O,
        sf::Keyboard::Key::Num0,
        sf::Keyboard::Key::P,
        sf::Keyboard::Key::LBracket,
        sf::Keyboard::Key::RBracket,
        sf::Keyboard::Key::Backslash
};

int numKeys = sizeof(keymap) / sizeof(keymap[0]);

bool IsKeyPressOnce(int keyCode)
{
        if (keyBuf[keyCode] && !keyBuf_last[keyCode]) return true;
        else return false;
}

class MyStream : public sf::SoundStream
{
public:

        void SetBufSize(int sz, int numChannel, int sampleRate)
        {
                m_samples.resize(sz, 0);
                m_currentSample = 0;
                initialize(numChannel, sampleRate);
        }

private:

        virtual bool onGetData(Chunk& data)
        {
                int len = m_samples.size();
                for (int i = 0; i < len; ++i)
                {
                        m_samples[i] = 0;
                }

                data.samples = &m_samples[m_currentSample];

                int k = 0;
                int c = 0;
                float s = 0;
                float increment = 0;

                for (k = 0; k < numKeys; k++)
                {
                        if (vol[k] <= 0) continue;

                        increment = PI2 * pow(2.0, (k + 3 + 12 * octave) / 12.0) * baseAFreq / sampleRate;

                        for (c = 0; c < audioBufSize; c += numChannel)
                        {
                                if (waveShapeType == ShapeMode::sine)
                                {
                                        s = m_samples[c] + sin(phase[k])*vol[k];
                                }
                                else if (waveShapeType == ShapeMode::triangle)
                                {
                                        double t2 = fmodf(phase[k], PI2) / (PI2);
                                        int t3 = floor(t2 + 0.5f);
                                        double t4 = fabs(t2 - t3) * 4 - 1;
                                        s = m_samples[c] + t4 * vol[k];
                                }
                                else if (waveShapeType == ShapeMode::saw)
                                {
                                        double t2 = phase[k] / PI2;
                                        int t3 = floor(t2 + 0.5f);
                                        double t4 = (t2 - t3) * 2;
                                        s = m_samples[c] + t4 * vol[k];
                                }
                                else if (waveShapeType == ShapeMode::square)
                                {
                                        double t2 = fmodf(phase[k], PI2) / (PI2);
                                        double t3 = t2 > 0.5 ? 1 : -1;
                                        s = m_samples[c] + t3 * vol[k];
                                }
                                else if (waveShapeType == ShapeMode::whiteNoise)
                                {
                                        s = rand() % 65536 - 32768;
                                }
                               
                                if (s > 32767) s = 32767;
                                else if (s < -32768) s = -32768;

                                m_samples[c] = s;
                                m_samples[c + 1] = s;

                                phase[k] += increment;

                                if (vol[k] < MAXVOL)
                                {
                                        vol[k] -= DECAY;
                                        if (vol[k] <= 0)
                                        {
                                                vol[k] = 0;
                                                break;
                                        }
                                }
                        }
                        phase[k] = fmod(phase[k], PI2);
                }

                data.sampleCount = audioBufSize;
                m_currentSample = 0;

                return true;
        }

        virtual void onSeek(sf::Time timeOffset)
        {
                m_currentSample = static_cast<std::size_t>(timeOffset.asSeconds() * getSampleRate() * getChannelCount());
        }

        std::vector<sf::Int16> m_samples;
        std::size_t m_currentSample;
};



int main()
{
        window.create(sf::VideoMode(ScreenWidth, ScreenHeight), "SFML2 Simple Audio Synth");

        MyStream stream;
        stream.SetBufSize(audioBufSize, numChannel, sampleRate);
        stream.play();

        while (window.isOpen())
        {
                sf::Event ev;
                while (window.pollEvent(ev))
                {
                        switch (ev.type)
                        {
                        case sf::Event::Closed: window.close(); break;
                        case sf::Event::KeyPressed:
                                keyBuf[ev.key.code] = true;
                                break;
                        case sf::Event::KeyReleased:
                                keyBuf[ev.key.code] = false;
                                break;
                        default:
                                break;
                        }
                }

                if (keyBuf[sf::Keyboard::Escape])
                {
                        window.close();
                }

                for (int key = 0; key < numKeys; ++key)
                {
                        if (keyBuf[keymap[key]] && vol[key] < MAXVOL)
                        {
                                phase[key] = 0;
                                vol[key] = MAXVOL + DECAY / 2;

                                int note = key + 12 * octave;

                                noteStr = to_string(note);
                                UpdateAllString();

                        }
                       
                        if(!keyBuf[keymap[key]] && vol[key] > 0)
                        {
                                vol[key] -= DECAY;
                        }
                }

                if (IsKeyPressOnce(sf::Keyboard::Key::Left))
                {
                        --waveShapeType;
                        waveShapeType = waveShapeType < 0 ? 4 : waveShapeType;

                        waveShapeStr = to_string(waveShapeType);
                        UpdateAllString();
                }
                if (IsKeyPressOnce(sf::Keyboard::Key::Right))
                {
                        ++waveShapeType;
                        waveShapeType = waveShapeType > 4 ? 0 : waveShapeType;

                        waveShapeStr = to_string(waveShapeType);
                        UpdateAllString();
                }

                if (IsKeyPressOnce(sf::Keyboard::Key::Down))
                {
                        --octave;
                        octave = octave < -3 ? -3 : octave;

                        octStr = to_string(octave);
                        UpdateAllString();
                }
                if (IsKeyPressOnce(sf::Keyboard::Key::Up))
                {
                        ++octave;
                        octave = octave > 4 ? 4 : octave;

                        octStr = to_string(octave);
                        UpdateAllString();
                }

                window.display();
                window.clear();

                sf::sleep(sf::microseconds(1));

                for (int k = 0; k < sf::Keyboard::Key::KeyCount; ++k)
                {
                        keyBuf_last[k] = keyBuf[k];
                }

        }

        return 0;
}

 

4

Feature requests / Drag drop file message information needed!

« on: December 15, 2018, 11:09:52 pm »

I'm using windows version,and SFML 2.5.1 does not support this.
Other framework such as SDL2,GLFW,bgfx,they all support drag drop file message.

It's easy to achieve with about 10 line codes,but I suggest SFML official built-in to do this.
That means I don't need to re-do this when I update SFML.

Just search WM_DROPFILES with SDL2 or GLFW or bgfx source code you will see how it works.