Streaming Audio

Problem: The current implementation reads the entire sound file in to memory in order to play it.
For OGG background music, this uses 91 Megs of RAM by injesting all ogg songs as well as all
wav assets.

Solution: Change StarAudio to play the asset from a file handle and stream it off the disk.
This results in a massive savings of RAM and doesn't really affect audio quality unless you're
doing massive disk operations such as compiling Starbound.

1 files changed, 39 insertions, 0 deletions

diff --git a/source/core/StarIODeviceCallbacks.cpp b/source/core/StarIODeviceCallbacks.cpp
new file mode 100644
index 0000000..ca8b692
--- /dev/null
+++ b/source/core/StarIODeviceCallbacks.cpp
@@ -0,0 +1,39 @@
+#include "StarIODeviceCallbacks.hpp"
+#include "vorbis/vorbisfile.h"
+
+namespace Star {
+
+IODeviceCallbacks::IODeviceCallbacks(IODevicePtr device) 
+  : m_device(std::move(device)) {
+  if (!m_device->isOpen())
+    m_device->open(IOMode::Read);
+}
+
+IODevicePtr const& IODeviceCallbacks::device() const {
+  return m_device;
+}
+
+size_t IODeviceCallbacks::readFunc(void* ptr, size_t size, size_t nmemb, void* datasource) {
+  auto* callbacks = static_cast<IODeviceCallbacks*>(datasource);
+  return callbacks->m_device->read((char*)ptr, size * nmemb) / size;
+}
+
+int IODeviceCallbacks::seekFunc(void* datasource, ogg_int64_t offset, int whence) {
+  auto* callbacks = static_cast<IODeviceCallbacks*>(datasource);
+  callbacks->m_device->seek(offset, (IOSeek)whence);
+  return 0;
+}
+
+long int IODeviceCallbacks::tellFunc(void* datasource) {
+  auto* callbacks = static_cast<IODeviceCallbacks*>(datasource);
+  return (long int)callbacks->m_device->pos();
+}
+
+void IODeviceCallbacks::setupOggCallbacks(ov_callbacks& callbacks) {
+  callbacks.read_func = readFunc;
+  callbacks.seek_func = seekFunc;
+  callbacks.tell_func = tellFunc;
+  callbacks.close_func = nullptr;
+}
+
+}
\ No newline at end of file