audio: allow to load a sample from raw data.

doc/tutorial/09_sound.cpp

@@ -17,6 +17,7 @@
 #include <lol/engine.h>
 
 #include <functional>
+#include <array>
 
 using namespace lol;
 
@@ -25,8 +26,17 @@ class sound_demo : public WorldEntity
 public:
     sound_demo()
     {
-        for (auto &val : m_streams)
-            val = -1;
+        for (int i = 0; i < 2; ++i)
+        {
+            auto f = std::bind(&sound_demo::synth, this, i,
+                               std::placeholders::_1,
+                               std::placeholders::_2);
+            m_streams[i] = audio::start_streaming(f);
+        }
+
+        for (size_t i = 0; i < m_instrument.size(); ++i)
+            m_instrument[i] = (int16_t)(i % 80 * (10000 - lol::abs(i - 10000)) * 40 / 10000);
+        m_sample = sample::create(m_instrument.data(), 40000);
 
         m_text = new Text("SPACE for sine wave, Left Click for white noise",
                           "data/font/ascii.png");
@@ -39,18 +49,25 @@ public:
         Ticker::Unref(m_text);
     }
 
-    void synth(int mode, void *buf, int bytes)
+    void synth(int channel, void *buf, int bytes)
     {
+        int mode = (1 << channel) & m_mask;
+
         int16_t *stream = (int16_t *)buf;
-        for (int i = 0; i < bytes / 2; ++i)
+        for (int i = 0; i < bytes / 2; i += 2)
         {
             switch (mode)
             {
-            case 0: // sine wave
-                stream[i] = lol::sin(4 * i * F_TAU / bytes) > 0 ? 800 : -800;
+            case 2: // square / triangle signals
+                stream[i] = 800 * (i % 128 > 64 ? -1 : 1);
+                stream[i + 1] = (i % 128 - 64) * 15;
                 break;
             case 1: // white noise
-                stream[i] = lol::rand(-200, 200);
+                stream[i] = lol::rand(-2000, 2000);
+                stream[i + 1] = lol::rand(-1000, 1000);
+                break;
+            case 0: // inactive
+                stream[i] = stream[i + 1] = 0;
                 break;
             }
         }
@@ -63,35 +80,28 @@ public:
         auto mouse = input::mouse();
         auto keyboard = input::keyboard();
 
-        for (int i = 0; i < 2; ++i)
-        {
-            if (i == 0 && !keyboard->key_pressed(input::key::SC_Space))
-                continue;
-            if (i == 1 && !mouse->button_pressed(input::button::BTN_Left))
-                continue;
+        if (keyboard->key_pressed(input::key::SC_Return))
+            m_sample->play();
 
-            if (m_streams[i] < 0)
-            {
-                auto f = std::bind(&sound_demo::synth, this, i,
-                                   std::placeholders::_1,
-                                   std::placeholders::_2);
-                m_streams[i] = audio::start_streaming(f);
-            }
-            else
-            {
-                audio::stop_streaming(m_streams[i]);
-                m_streams[i] = -1;
-            }
-        }
+        if (keyboard->key_pressed(input::key::SC_Space))
+            m_mask ^= 2;
+
+        if (mouse->button_pressed(input::button::BTN_Left))
+            m_mask ^= 1;
     }
 
-    virtual void tick_draw(float seconds, Scene &scene) override
+    virtual bool release_game() override
     {
-        WorldEntity::tick_draw(seconds, scene);
+        for (int i = 0; i < 2; ++i)
+            audio::stop_streaming(m_streams[i]);
+        return true;
     }
 
 private:
     int m_streams[2];
+    int m_mask = 0;
+    std::array<int16_t, 20000> m_instrument;
+    sample* m_sample;
     Text *m_text;
 };
 

src/audio/audio.cpp

@@ -12,6 +12,7 @@
 
 #include <lol/engine-internal.h>
 
+#include <array>
 #include <unordered_set>
 #include <functional>
 
@@ -25,6 +26,13 @@
 #   endif
 #endif
 
+// Buffer size, in samples (https://wiki.libsdl.org/SDL_AudioSpec)
+// “[…] refers to the size of the audio buffer in sample frames. A sample frame
+// is a chunk of audio data of the size specified in format multiplied by the
+// number of channels.”
+#define LOL_AUDIO_SAMPLE_FRAMES 1024
+#define LOL_AUDIO_CHANNELS 2
+
 namespace lol
 {
 
@@ -32,8 +40,8 @@ struct audio_streamer
 {
     int m_channel;
     std::function<void(void *, int)> m_callback;
+    std::array<uint16_t, LOL_AUDIO_CHANNELS * LOL_AUDIO_SAMPLE_FRAMES> m_empty; // SDL needs a reference to this
 #if defined LOL_USE_SDL_MIXER
-    std::vector<uint8_t> m_empty; // SDL keeps a reference to this
     Mix_Chunk *m_chunk;
 #endif
 };
@@ -47,7 +55,7 @@ std::unordered_set<std::shared_ptr<audio_streamer>> audio::m_streamers;
 #if defined LOL_USE_SDL_MIXER
 void audio::init()
 {
-    Mix_OpenAudio(22050, AUDIO_S16, 2, 1024);
+    Mix_OpenAudio(22050, AUDIO_S16, LOL_AUDIO_CHANNELS, LOL_AUDIO_SAMPLE_FRAMES);
     set_channels(8);
 }
 
@@ -79,12 +87,13 @@ int audio::start_streaming(std::function<void(void *, int)> const &f)
         s->m_callback(stream, bytes);
     };
 
-    std::shared_ptr<audio_streamer> s = std::make_shared<audio_streamer>();
+    auto s = std::make_shared<audio_streamer>();
     m_streamers.insert(s);
 
-    s->m_empty.resize(1024);
-    s->m_chunk = Mix_QuickLoad_RAW(s->m_empty.data(),
-            (Uint32)(s->m_empty.size() * sizeof(uint8_t)));
+    Uint8* audio_data = (Uint8*)s->m_empty.data();
+    Uint32 audio_size = (Uint32)(s->m_empty.size() * sizeof(s->m_empty[0]));
+    memset(audio_data, 17, audio_size);
+    s->m_chunk = Mix_QuickLoad_RAW(audio_data, audio_size);
     s->m_channel = Mix_PlayChannel(-1, s->m_chunk, -1);
     s->m_callback = f;
     Mix_RegisterEffect(s->m_channel, trampoline, nullptr, s.get());

src/audio/sample.cpp

@@ -58,6 +58,11 @@ sample *sample::create(std::string const &path)
     return ret ? ret : sample_cache.set(path, new sample(path));
 }
 
+sample *sample::create(void const *samples, size_t len)
+{
+    return new sample(samples, len);
+}
+
 void sample::destroy(sample *s)
 {
     // FIXME: decrement!
@@ -65,7 +70,7 @@ void sample::destroy(sample *s)
 }
 
 sample::sample(std::string const &path)
-  : data(new sample_data())
+  : data(std::make_unique<sample_data>())
 {
     data->m_name = std::string("<sample> ") + path;
 
@@ -84,13 +89,23 @@ sample::sample(std::string const &path)
 #endif
 }
 
+sample::sample(void const *samples, size_t len)
+  : data(std::make_unique<sample_data>())
+{
+    data->m_name = std::string("<sample>");
+
+#if defined LOL_USE_SDL_MIXER
+    data->m_chunk = Mix_QuickLoad_RAW((Uint8 *)samples, (Uint32)len);
+    data->m_channel = -1;
+#endif
+}
+
 sample::~sample()
 {
 #if defined LOL_USE_SDL_MIXER
     if (data->m_chunk)
         Mix_FreeChunk(data->m_chunk);
 #endif
-    delete data;
 }
 
 void sample::tick_game(float seconds)

src/lol/audio/sample.h

@@ -25,16 +25,16 @@
 namespace lol
 {
 
-class sample_data;
-
 class sample : public entity
 {
 public:
     static sample *create(std::string const &path);
+    static sample* create(void const* samples, size_t len);
     static void destroy(sample *s);
 
 protected:
     sample(std::string const &path);
+    sample(void const *samples, size_t len);
     virtual ~sample();
 
     /* Inherited from entity */
@@ -48,7 +48,7 @@ public:
     void stop();
 
 private:
-    sample_data *data;
+    std::unique_ptr<class sample_data> data;
 };
 
 } /* namespace lol */

src/ui/sdl-input.cpp

@@ -197,8 +197,8 @@ void SdlInput::tick(float seconds)
 
         //case SDL_TEXTEDITING: //TODO: handle that?
         case SDL_TEXTINPUT:
-                keyboard->internal_add_text(event.text.text);
-                break;
+            keyboard->internal_add_text(event.text.text);
+            break;
 
         case SDL_MOUSEBUTTONDOWN:
         case SDL_MOUSEBUTTONUP: