[Perf] (MG_Backend/DirectVulkan): cache resolved VkSampler per binding to skip the per-draw sampler key hash, keyed on a new sampler lifetime id

MobileGL/MG_State/GLState/SamplerState/SamplerObject.cpp

@@ -8,10 +8,19 @@
 
 #include "SamplerObject.h"
 
+#include <atomic>
+
 namespace MobileGL {
     namespace MG_State {
         namespace GLState {
-            SamplerObject::SamplerObject(Uint externalIndex) : m_externalIndex(externalIndex) {}
+            static std::atomic<Uint64> s_nextSamplerLifetimeId = 1;
+
+            Uint64 SamplerObject::AllocateLifetimeId() {
+                return s_nextSamplerLifetimeId.fetch_add(1, std::memory_order_relaxed);
+            }
+
+            SamplerObject::SamplerObject(Uint externalIndex)
+                : m_externalIndex(externalIndex), m_lifetimeId(AllocateLifetimeId()) {}
 
             void SamplerObject::SetWrapS(SamplerWrapMode mode) {
                 if (mode == m_samplerParameters.wrapS) return;
@@ -138,6 +147,10 @@ namespace MobileGL {
             Uint16 SamplerObject::GetVersion() const {
                 return m_version;
             }
+
+            Uint64 SamplerObject::GetLifetimeId() const {
+                return m_lifetimeId;
+            }
         } // namespace GLState
     } // namespace MG_State
 } // namespace MobileGL

MobileGL/MG_State/GLState/SamplerState/SamplerObject.h

@@ -99,10 +99,18 @@ namespace MobileGL {
                 SamplerCompareFunc GetSamplerCompareFunc() const;
                 Uint GetExternalIndex() const;
                 Uint16 GetVersion() const;
+                // Globally-unique, never-reused id for this sampler object's lifetime. Lets a
+                // cache distinguish a freed-and-reallocated sampler (same heap address, GL name,
+                // or version count) from the original - the sampler analogue of the texture
+                // lifetime id. Used by the Vulkan backend's per-binding sampler fast path.
+                Uint64 GetLifetimeId() const;
                 const SamplerParameters& GetAllSamplerParameters() const;
 
             private:
+                static Uint64 AllocateLifetimeId();
+
                 const Uint m_externalIndex;
+                const Uint64 m_lifetimeId;
                 Uint16 m_version = 0;
                 SamplerParameters m_samplerParameters;
             };