Merge remote-tracking branch 'tmj/master' into sim

audiorenderer_extra.h

@@ -0,0 +1,55 @@
+// separate file because of include dependecies mess
+
+namespace audio {
+template <class Iterator_>
+openal_source &
+openal_source::bind( sound_source *Controller, uint32_sequence Sounds, Iterator_ First, Iterator_ Last ) {
+
+    controller = Controller;
+    sounds = Sounds;
+    // look up and queue assigned buffers
+    std::vector<ALuint> buffers;
+    std::for_each(
+        First, Last,
+        [&]( audio::buffer_handle const &bufferhandle ) {
+            auto const &buffer { audio::renderer.buffer( bufferhandle ) };
+			if (buffer.id != null_resource) buffers.emplace_back( buffer.id ); } );
+
+    is_multipart = ( buffers.size() > 1 );
+
+    if( id != audio::null_resource ) {
+        ::alSourceQueueBuffers( id, static_cast<ALsizei>( buffers.size() ), buffers.data() );
+        ::alSourceRewind( id );
+        // sound controller can potentially request playback to start from certain buffer point
+        if( controller->start() == 0.f ) {
+            // regular case with no offset, reset bound source just in case
+            ::alSourcei( id, AL_SAMPLE_OFFSET, 0 );
+        }
+        else {
+            // move playback start to specified point in 0-1 range
+            ALint buffersize;
+            ::alGetBufferi( buffers.front(), AL_SIZE, &buffersize );
+            ::alSourcei(
+                id,
+                AL_SAMPLE_OFFSET,
+                static_cast<ALint>( controller->start() * ( buffersize / sizeof( std::int16_t ) ) ) );
+        }
+    }
+
+    return *this;
+}
+
+inline
+float
+amplitude_to_db( float const Amplitude ) {
+
+    return 20.f * std::log10( Amplitude );
+}
+
+inline
+float
+db_to_amplitude( float const Decibels ) {
+
+    return std::pow( 10.f, Decibels / 20.f );
+}
+}