1 files changed, 171 insertions, 0 deletions
diff --git a/core/context.h b/core/context.h
new file mode 100644
index 00000000..bf439053
--- /dev/null
+++ b/core/context.h
@@ -0,0 +1,171 @@
+#ifndef CORE_CONTEXT_H
+#define CORE_CONTEXT_H
+
+#include <array>
+#include <atomic>
+#include <cstddef>
+#include <memory>
+#include <thread>
+
+#include "almalloc.h"
+#include "alspan.h"
+#include "atomic.h"
+#include "core/bufferline.h"
+#include "threads.h"
+#include "vecmat.h"
+#include "vector.h"
+
+struct DeviceBase;
+struct EffectSlot;
+struct EffectSlotProps;
+struct RingBuffer;
+struct Voice;
+struct VoiceChange;
+struct VoicePropsItem;
+
+using uint = unsigned int;
+
+
+constexpr float SpeedOfSoundMetersPerSec{343.3f};
+
+enum class DistanceModel : unsigned char {
+    Disable,
+    Inverse, InverseClamped,
+    Linear, LinearClamped,
+    Exponent, ExponentClamped,
+
+    Default = InverseClamped
+};
+
+
+struct WetBuffer {
+    bool mInUse;
+    al::FlexArray<FloatBufferLine, 16> mBuffer;
+
+    WetBuffer(size_t count) : mBuffer{count} { }
+
+    DEF_FAM_NEWDEL(WetBuffer, mBuffer)
+};
+using WetBufferPtr = std::unique_ptr<WetBuffer>;
+
+
+struct ContextProps {
+    float DopplerFactor;
+    float DopplerVelocity;
+    float SpeedOfSound;
+    bool SourceDistanceModel;
+    DistanceModel mDistanceModel;
+
+    std::atomic<ContextProps*> next;
+
+    DEF_NEWDEL(ContextProps)
+};
+
+struct ListenerProps {
+    std::array<float,3> Position;
+    std::array<float,3> Velocity;
+    std::array<float,3> OrientAt;
+    std::array<float,3> OrientUp;
+    float Gain;
+    float MetersPerUnit;
+
+    std::atomic<ListenerProps*> next;
+
+    DEF_NEWDEL(ListenerProps)
+};
+
+struct ContextParams {
+    /* Pointer to the most recent property values that are awaiting an update. */
+    std::atomic<ContextProps*> ContextUpdate{nullptr};
+    std::atomic<ListenerProps*> ListenerUpdate{nullptr};
+
+    alu::Matrix Matrix{alu::Matrix::Identity()};
+    alu::Vector Velocity{};
+
+    float Gain{1.0f};
+    float MetersPerUnit{1.0f};
+
+    float DopplerFactor{1.0f};
+    float SpeedOfSound{343.3f}; /* in units per sec! */
+
+    bool SourceDistanceModel{false};
+    DistanceModel mDistanceModel{};
+};
+
+struct ContextBase {
+    DeviceBase *const mDevice;
+
+    /* Counter for the pre-mixing updates, in 31.1 fixed point (lowest bit
+     * indicates if updates are currently happening).
+     */
+    RefCount mUpdateCount{0u};
+    std::atomic<bool> mHoldUpdates{false};
+    std::atomic<bool> mStopVoicesOnDisconnect{true};
+
+    float mGainBoost{1.0f};
+
+    /* Linked lists of unused property containers, free to use for future
+     * updates.
+     */
+    std::atomic<ContextProps*> mFreeContextProps{nullptr};
+    std::atomic<ListenerProps*> mFreeListenerProps{nullptr};
+    std::atomic<VoicePropsItem*> mFreeVoiceProps{nullptr};
+    std::atomic<EffectSlotProps*> mFreeEffectslotProps{nullptr};
+
+    /* The voice change tail is the beginning of the "free" elements, up to and
+     * *excluding* the current. If tail==current, there's no free elements and
+     * new ones need to be allocated. The current voice change is the element
+     * last processed, and any after are pending.
+     */
+    VoiceChange *mVoiceChangeTail{};
+    std::atomic<VoiceChange*> mCurrentVoiceChange{};
+
+    void allocVoiceChanges(size_t addcount);
+
+
+    ContextParams mParams;
+
+    using VoiceArray = al::FlexArray<Voice*>;
+    std::atomic<VoiceArray*> mVoices{};
+    std::atomic<size_t> mActiveVoiceCount{};
+
+    void allocVoices(size_t addcount);
+    al::span<Voice*> getVoicesSpan() const noexcept
+    {
+        return {mVoices.load(std::memory_order_relaxed)->data(),
+            mActiveVoiceCount.load(std::memory_order_relaxed)};
+    }
+    al::span<Voice*> getVoicesSpanAcquired() const noexcept
+    {
+        return {mVoices.load(std::memory_order_acquire)->data(),
+            mActiveVoiceCount.load(std::memory_order_acquire)};
+    }
+
+
+    using EffectSlotArray = al::FlexArray<EffectSlot*>;
+    std::atomic<EffectSlotArray*> mActiveAuxSlots{nullptr};
+
+    std::thread mEventThread;
+    al::semaphore mEventSem;
+    std::unique_ptr<RingBuffer> mAsyncEvents;
+    std::atomic<uint> mEnabledEvts{0u};
+
+    /* Asynchronous voice change actions are processed as a linked list of
+     * VoiceChange objects by the mixer, which is atomically appended to.
+     * However, to avoid allocating each object individually, they're allocated
+     * in clusters that are stored in a vector for easy automatic cleanup.
+     */
+    using VoiceChangeCluster = std::unique_ptr<VoiceChange[]>;
+    al::vector<VoiceChangeCluster> mVoiceChangeClusters;
+
+    using VoiceCluster = std::unique_ptr<Voice[]>;
+    al::vector<VoiceCluster> mVoiceClusters;
+
+
+    ContextBase(DeviceBase *device);
+    ContextBase(const ContextBase&) = delete;
+    ContextBase& operator=(const ContextBase&) = delete;
+    ~ContextBase();
+};
+
+#endif /* CORE_CONTEXT_H */