Support for changing the game's timescale

Context-specific (like per-world) timescales can also be added later

2 files changed, 17 insertions, 2 deletions

diff --git a/source/base/StarMixer.cpp b/source/base/StarMixer.cpp
index c38d17e..2ec6b9e 100644
--- a/source/base/StarMixer.cpp
+++ b/source/base/StarMixer.cpp
@@ -172,6 +172,8 @@ Mixer::Mixer(unsigned sampleRate, unsigned channels) {
   m_groupVolumes[MixerGroup::Effects] = {1.0f, 1.0f, 0};
   m_groupVolumes[MixerGroup::Music] = {1.0f, 1.0f, 0};
   m_groupVolumes[MixerGroup::Cinematic] = {1.0f, 1.0f, 0};
+
+  m_speed = 1.0f;
 }
 
 unsigned Mixer::sampleRate() const {
@@ -203,6 +205,10 @@ bool Mixer::hasEffect(String const& effectName) {
   return m_effects.contains(effectName);
 }
 
+void Mixer::setSpeed(float speed) {
+  m_speed = speed;
+}
+
 void Mixer::setVolume(float volume, float rampTime) {
   MutexLocker locker(m_mutex);
   m_volume.target = volume;
@@ -259,6 +265,8 @@ void Mixer::read(int16_t* outBuffer, size_t frameCount, ExtraMixFunction extraMi
   for (size_t i = 0; i < bufferSize; ++i)
     outBuffer[i] = 0;
 
+  float speed = m_speed;
+
   {
     MutexLocker locker(m_queueMutex);
     // Mix all active sounds
@@ -288,6 +296,9 @@ void Mixer::read(int16_t* outBuffer, size_t frameCount, ExtraMixFunction extraMi
           ? approach(audioInstance->m_pitchMultiplierTarget, audioInstance->m_pitchMultiplier, audioInstance->m_pitchMultiplierVelocity * time)
           : audioInstance->m_pitchMultiplier;
 
+      if (audioInstance->m_mixerGroup == MixerGroup::Effects)
+        pitchMultiplier *= speed;
+
       if (audioStopVolEnd == 0.0f && audioInstance->m_stopping)
         finished = true;
 
@@ -461,7 +472,7 @@ void Mixer::setGroupVolume(MixerGroup group, float targetValue, float rampTime)
   }
 }
 
-void Mixer::update(PositionalAttenuationFunction positionalAttenuationFunction) {
+void Mixer::update(float dt, PositionalAttenuationFunction positionalAttenuationFunction) {
   {
     MutexLocker locker(m_queueMutex);
     eraseWhere(m_audios, [&](auto& p) {
diff --git a/source/base/StarMixer.hpp b/source/base/StarMixer.hpp
index d369cfb..f87f5be 100644
--- a/source/base/StarMixer.hpp
+++ b/source/base/StarMixer.hpp
@@ -115,6 +115,9 @@ public:
   StringList currentEffects();
   bool hasEffect(String const& effectName);
 
+  // Global speed
+  void setSpeed(float speed);
+
   // Global volume
   void setVolume(float volume, float rampTime);
 
@@ -131,7 +134,7 @@ public:
 
   // Call within the main loop of the program using Mixer, calculates
   // positional attenuation of audio and does cleanup.
-  void update(PositionalAttenuationFunction positionalAttenuationFunction = {});
+  void update(float dt, PositionalAttenuationFunction positionalAttenuationFunction = {});
 
 private:
   struct EffectInfo {
@@ -161,6 +164,7 @@ private:
   List<int16_t> m_mixBuffer;
 
   Map<MixerGroup, RampedValue> m_groupVolumes;
+  atomic<float> m_speed;
 };
 
 }