Merge pull request #2058 from cameronwhite/dev_extcomp_dependencymap

Fix bug in HdExtComputationUtils::_GenerateDependencyMap() with multiple input computations (Internal change: 2256749)
PixarAnimationStudios · Dec 8, 2022 · c0aed8a · c0aed8a
2 parents ab0ef74 + faa5eda
commit c0aed8a
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Showing 2 changed files with 34 additions and 16 deletions.
diff --git a/pxr/imaging/hd/extComputationUtils.cpp b/pxr/imaging/hd/extComputationUtils.cpp
@@ -68,7 +68,7 @@ HdExtComputationUtils::_GenerateDependencyMap(
     HdExtComputationUtils::ComputationDependencyMap cdm;
     while (!computations.empty()) {
         // Pop head entry and skip if already processed.
-        HdExtComputation const * curComp = computations.back();
+        HdExtComputation const * curComp = computations.front();
         computations.pop_front();
         if (cdm.find(curComp) != cdm.end()) {
             continue;

diff --git a/pxr/imaging/hd/testenv/testHdExtComputationUtils.cpp b/pxr/imaging/hd/testenv/testHdExtComputationUtils.cpp
@@ -36,13 +36,20 @@
 PXR_NAMESPACE_USING_DIRECTIVE
 
 static const SdfPath pathA("/path/to/A");
-static const SdfPath compA("/path/to/A/computation");
+static const SdfPath compA("/path/to/A/computationA");
+static const SdfPath compB("/path/to/A/computationB");
+static const SdfPath compC("/path/to/A/computationC");
 static const TfToken input1("input1");
 static const TfToken input2("input2");
 static const TfToken primvarName("outputPV");
 static const TfToken compOutputName("compOutput");
 
-// Delegate that implements a simple computation (adding together two inputs).
+// Delegate that implements a simple computation, which adds together inputs
+// from two aggregate computations:
+//
+// computationA -> computationB -> input1
+//             \-> computationC -> input2
+//
 class ExtComputationTestDelegate : public HdUnitTestDelegate {
 public:
     ExtComputationTestDelegate(HdRenderIndex *parentIndex)
@@ -71,13 +78,26 @@ class ExtComputationTestDelegate : public HdUnitTestDelegate {
 
     virtual TfTokenVector
     GetExtComputationSceneInputNames(SdfPath const& computationId) override {
-        if (computationId == compA) {
-            return {input1, input2};
+        if (computationId == compB) {
+            return {input1};
+        } else if (computationId == compC) {
+            return {input2};
         }
 
         return {};
     }
 
+    virtual HdExtComputationInputDescriptorVector
+    GetExtComputationInputDescriptors(SdfPath const& computationId) override {
+        HdExtComputationInputDescriptorVector inputs;
+        if (computationId == compA) {
+            inputs.emplace_back(input1, compB, input1);
+            inputs.emplace_back(input2, compC, input2);
+        }
+
+        return inputs;
+    }
+
     virtual HdExtComputationOutputDescriptorVector
     GetExtComputationOutputDescriptors(SdfPath const& computationId) override {
         HdExtComputationOutputDescriptorVector outputs;
@@ -96,21 +116,17 @@ class ExtComputationTestDelegate : public HdUnitTestDelegate {
                                              size_t maxSampleCount,
                                              float *sampleTimes,
                                              VtValue *sampleValues) override {
-        if (computationId != compA) {
-            return 0;
-        }
-
         const size_t numSamples = std::min(size_t(4), maxSampleCount);
 
         // The two inputs have different sample times (0,1,2,3 and 0,2,4,6).
-        if (input == input1) {
+        if (computationId == compB && input == input1) {
             for (size_t i = 0; i < numSamples; ++i) {
                 sampleTimes[i] = i;
                 sampleValues[i] = VtValue(double(i));
             }
             return numSamples;
         }
-        else if (input == input2) {
+        else if (computationId == compC && input == input2) {
             for (size_t i = 0; i < numSamples; ++i) {
                 sampleTimes[i] = i * 2;
                 sampleValues[i] = VtValue(double(i));
@@ -218,11 +234,13 @@ void RunTest()
         HdRenderIndex::New(&renderDelegate, {}));
     ExtComputationTestDelegate delegate(index.get());
 
-    // Create an sprim for the computation.
-    index->InsertSprim(HdPrimTypeTokens->extComputation, &delegate, compA);
-    auto sprim = index->GetSprim(HdPrimTypeTokens->extComputation, compA);
-    HdDirtyBits dirty = HdExtComputation::DirtyBits::AllDirty;
-    sprim->Sync(&delegate, nullptr, &dirty);
+    // Create an sprim for each computation.
+    for (const SdfPath &comp : {compA, compB, compC}) {
+        index->InsertSprim(HdPrimTypeTokens->extComputation, &delegate, comp);
+        auto sprim = index->GetSprim(HdPrimTypeTokens->extComputation, comp);
+        HdDirtyBits dirty = HdExtComputation::DirtyBits::AllDirty;
+        sprim->Sync(&delegate, nullptr, &dirty);
+    }
 
     auto compPrimvars = delegate.GetExtComputationPrimvarDescriptors(
         pathA, HdInterpolationConstant);