audio subsystem: openal emitter, minor audio fixes

audiorenderer.h

@@ -10,9 +10,60 @@ http://mozilla.org/MPL/2.0/.
 #pragma once
 
 #include "audio.h"
+#include "resourcemanager.h"
+
+class sound_source;
 
 namespace audio {
 
+// implementation part of the sound emitter
+// TODO: generic interface base, for implementations other than openAL
+struct openal_source {
+
+// types
+    using buffer_sequence = std::vector<audio::buffer_handle>;
+
+// members
+    ALuint id { audio::null_resource }; // associated AL resource
+    sound_source *controller { nullptr }; // source controller 
+    buffer_sequence buffers; // sequence of samples the source will emit
+    int buffer_index; // currently queued sample from the buffer sequence
+    bool is_playing { false };
+
+// methods
+    template <class Iterator_>
+    openal_source &
+        bind( sound_source *Controller, Iterator_ First, Iterator_ Last ) {
+            controller = Controller;
+            buffers.insert( std::end( buffers ), First, Last );
+            if( id == audio::null_resource ) {
+                ::alGenSources( 1, &id ); }
+            // look up and queue assigned buffers
+            std::vector<ALuint> bufferids;
+            for( auto const buffer : buffers ) {
+                bufferids.emplace_back( audio::renderer.buffer( buffer ).id ); }
+            ::alSourceQueueBuffers( id, bufferids.size(), bufferids.data() );
+            return *this; }
+    // starts playback of queued buffers
+    void
+        play();
+    // stops the playback
+    void
+        stop();
+    // updates state of the source
+    void
+        update( int const Deltatime );
+    // toggles looping of the sound emitted by the source
+   void
+        loop( bool const State );
+    // releases bound buffers and resets state of the class variables
+    // NOTE: doesn't release allocated implementation-side source
+    void
+        clear();
+};
+
+
+
 class openal_renderer {
 
 public:
@@ -21,23 +72,46 @@ public:
 // methods
     // buffer methods
     // returns handle to a buffer containing audio data from specified file
-    buffer_handle
+    audio::buffer_handle
         fetch_buffer( std::string const &Filename );
+    // provides direct access to a specified buffer
+    audio::openal_buffer const &
+        buffer( audio::buffer_handle const Buffer ) const;
     // core methods
     // initializes the service
     bool
         init();
+    // schedules playback of provided range of samples, under control of the specified sound emitter
+    template <class Iterator_>
+    void
+        insert( sound_source *Controller, Iterator_ First, Iterator_ Last ) {
+            m_sources.emplace_back( fetch_source().bind( Controller, First, Last ) ); }
+    // schedules playback of specified sample, under control of the specified sound emitter
+    void
+        insert( sound_source *Controller, audio::buffer_handle const Sound );
+    // updates state of all active emitters
+    void
+        update( int const Deltatime );
 
 private:
+// types
+    using source_list = std::list<audio::openal_source>;
+    using source_sequence = std::stack<audio::openal_source>;
 // methods
     bool
         init_caps();
+    // returns an instance of implementation-side part of the sound emitter
+    audio::openal_source
+        fetch_source();
 // members
     ALCdevice * m_device { nullptr };
     ALCcontext * m_context { nullptr };
     bool m_ready { false }; // renderer is initialized and functional
 
     buffer_manager m_buffers;
+    // TBD: list of sources as vector, sorted by distance, for openal implementations with limited number of active sources?
+    source_list m_sources;
+    source_sequence m_sourcespares; // already created and currently unused sound sources
 };
 
 extern openal_renderer renderer;