Merge pull request #1276 from CesiumGS/removed-credit-sources

Report credits with destroyed source as removed.

CesiumUtility/include/CesiumUtility/CreditSystem.h

@@ -315,6 +315,11 @@ private:
   CreditsSnapshot _snapshot;
   std::vector<int32_t> _referenceCountScratch;
 
+  // These are credits that were shown in the last snapshot but whose
+  // CreditSources have since been destroyed. They need to be reported in
+  // removedCredits in the next snapshot.
+  std::vector<Credit> _shownCreditsDestroyed;
+
   // Each entry in this vector is an index into _credits that is unused and can
   // be reused for a new credit.
   std::vector<size_t> _unusedCreditRecords;

CesiumUtility/src/CreditSystem.cpp

@@ -191,7 +191,11 @@ CreditSystem::getSnapshot(CreditFilteringMode filteringMode) noexcept {
   std::vector<Credit>& currentCredits = this->_snapshot.currentCredits;
   std::vector<Credit>& removedCredits = this->_snapshot.removedCredits;
   currentCredits.clear();
-  removedCredits.clear();
+
+  // Any credits that were shown last snapshot and whose sources have since been
+  // destroyed need to be reported in removedCredits.
+  removedCredits = this->_shownCreditsDestroyed;
+  this->_shownCreditsDestroyed.clear();
 
   std::vector<int32_t>& effectiveReferenceCounts = this->_referenceCountScratch;
   effectiveReferenceCounts.assign(this->_credits.size(), 0);
@@ -290,6 +294,12 @@ void CreditSystem::createCreditSource(CreditSource& creditSource) noexcept {
 void CreditSystem::destroyCreditSource(CreditSource& creditSource) noexcept {
   for (CreditRecord& record : this->_credits) {
     if (record.pSource == &creditSource) {
+      if (record.shownLastSnapshot) {
+        this->_shownCreditsDestroyed.emplace_back(Credit(
+            uint32_t(&record - this->_credits.data()),
+            record.generation));
+      }
+
       record.pSource = nullptr;
       ++record.generation;
       this->_unusedCreditRecords.emplace_back(&record - this->_credits.data());

CesiumUtility/test/TestCreditSystem.cpp

@@ -243,7 +243,7 @@ TEST_CASE("Test CreditSystem with CreditSources") {
   }
 
   SUBCASE("when the source of a credit last frame is destroyed, that credit is "
-          "not reported") {
+          "reported in removedCredits") {
     std::unique_ptr<CreditSource> pTempSourceA =
         std::make_unique<CreditSource>(creditSystem);
     Credit credit0 = creditSystem.createCredit(*pTempSourceA, html0);
@@ -257,13 +257,14 @@ TEST_CASE("Test CreditSystem with CreditSources") {
     // this credit would show up in the `removedCredits`.
     creditSystem.removeCreditReference(credit0);
 
-    // Destroy the source. Now, the removed credit should no longer be reported
-    // in the next snapshot.
+    // Destroy the source. The removed credit should still be reported in the
+    // next snapshot.
     pTempSourceA.reset();
 
     const CreditsSnapshot& snapshot1 = creditSystem.getSnapshot();
     CHECK(snapshot1.currentCredits.empty());
-    CHECK(snapshot1.removedCredits.empty());
+    CHECK(snapshot1.removedCredits.size() == 1);
+    CHECK(snapshot1.removedCredits[0] == credit0);
   }
 
   SUBCASE("CreditSystem may be destroyed before CreditSource") {