Merge pull request 'perf(mesh): release per-mesh scratch buffer for static BLAS (#66)' (#104) from claude/issue-66 into master

implementations/Crafter.Graphics-Mesh.cpp

@@ -152,6 +152,23 @@ namespace {
 
         self.buildFlags          = flags;
         self.builtPrimitiveCount = primitiveCount;
+
+        // Static (!allowUpdate) meshes can never refit, so their per-mesh
+        // scratch is dead weight the moment this build's GPU work completes —
+        // release it instead of keeping a persistent DEVICE_LOCAL allocation
+        // per mesh (the waste that dominates many-mesh scenes, issue #66). The
+        // fresh build recorded above still reads scratchBuffer.address from
+        // this command buffer, so a plain Clear() would be a use-after-free;
+        // DeferredClear() retires the allocation only once the build's frame
+        // has passed its fence (the queue from #101/#102). A later Refit on a
+        // static mesh takes the rebuild fallback, whose Resize sees the nulled
+        // handle and re-Creates the scratch. Refit-capable meshes keep theirs:
+        // an in-place UPDATE reuses it every frame (build scratch ≥ update
+        // scratch, so no resize). Only applies to a fresh build — an UPDATE
+        // never reaches here for a static mesh.
+        if (!update && !self.allowUpdate) {
+            self.scratchBuffer.DeferredClear();
+        }
     }
 
     void RecordBLASBuild(Mesh& self, std::uint32_t vertexCount, std::uint32_t indexCount, VkBuildAccelerationStructureFlagsKHR flags, bool update, VkCommandBuffer cmd) {