Add function to format clip results using a gather operation

If an index in the format is -1 put a default value of 0 into the
formatted results. This will allow clips to not have to provide every
channel used anywhere by the blend tree.

Change-Id: I9e18d0840e75a959ef680cbd54259a74c9331fa8
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

3 files changed, 90 insertions, 0 deletions

diff --git a/src/animation/backend/animationutils.cpp b/src/animation/backend/animationutils.cpp
index 8f1a681d4..8b2ba6821 100644
--- a/src/animation/backend/animationutils.cpp
+++ b/src/animation/backend/animationutils.cpp
@@ -369,6 +369,24 @@ QVector<Qt3DCore::QNodeId> gatherValueNodesToEvaluate(Handler *handler,
     return clipIds;
 }
 
+ClipResults formatClipResults(const ClipResults &rawClipResults,
+                              const ComponentIndices &format)
+{
+    // Resize the output to match the number of indices
+    const int elementCount = format.size();
+    ClipResults formattedClipResults(elementCount);
+
+    // Perform a gather operation to format the data
+    // TODO: For large numbers of components do this in parallel with
+    // for e.g. a parallel_for() like construct
+    for (int i = 0; i < elementCount; ++i) {
+        const float value = format[i] != -1 ? rawClipResults[format[i]] : 0.0f;
+        formattedClipResults[i] = value;
+    }
+
+    return formattedClipResults;
+}
+
 ClipResults evaluateBlendTree(Handler *handler,
                               BlendedClipAnimator *animator,
                               Qt3DCore::QNodeId blendTreeRootId)
diff --git a/src/animation/backend/animationutils_p.h b/src/animation/backend/animationutils_p.h
index da85451f8..705e37c34 100644
--- a/src/animation/backend/animationutils_p.h
+++ b/src/animation/backend/animationutils_p.h
@@ -173,6 +173,10 @@ QVector<Qt3DCore::QNodeId> gatherValueNodesToEvaluate(Handler *handler,
                                                       Qt3DCore::QNodeId blendTreeRootId);
 
 Q_AUTOTEST_EXPORT
+ClipResults formatClipResults(const ClipResults &rawClipResults,
+                              const ComponentIndices &format);
+
+Q_AUTOTEST_EXPORT
 ClipResults evaluateBlendTree(Handler *handler,
                               BlendedClipAnimator *animator,
                               Qt3DCore::QNodeId blendNodeId);
diff --git a/tests/auto/animation/animationutils/tst_animationutils.cpp b/tests/auto/animation/animationutils/tst_animationutils.cpp
index dcdbafdae..6f0c998e6 100644
--- a/tests/auto/animation/animationutils/tst_animationutils.cpp
+++ b/tests/auto/animation/animationutils/tst_animationutils.cpp
@@ -1885,6 +1885,74 @@ private Q_SLOTS:
         // Cleanup
         delete handler;
     }
+
+    void checkFormatClipResults_data()
+    {
+        QTest::addColumn<ClipResults>("rawClipResults");
+        QTest::addColumn<ComponentIndices>("format");
+        QTest::addColumn<ClipResults>("expectedResults");
+
+        {
+            ClipResults rawClipResults = { 1.0f, 2.0f, 3.0f };
+            ComponentIndices format = { 0, 1, 2 };
+            ClipResults expectedResults = { 1.0f, 2.0f, 3.0f };
+
+            QTest::newRow("identity")
+                    << rawClipResults << format << expectedResults;
+        }
+
+        {
+            ClipResults rawClipResults = { 1.0f, 2.0f };
+            ComponentIndices format = { 1, 0 };
+            ClipResults expectedResults = { 2.0f, 1.0f };
+
+            QTest::newRow("swap")
+                    << rawClipResults << format << expectedResults;
+        }
+
+        {
+            ClipResults rawClipResults = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
+            ComponentIndices format = { 0, 2, 1, 3, 4 };
+            ClipResults expectedResults = { 1.0f, 3.0f, 2.0f, 4.0f, 5.0f };
+
+            QTest::newRow("swap subset")
+                    << rawClipResults << format << expectedResults;
+        }
+
+        {
+            ClipResults rawClipResults = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
+            ComponentIndices format = { 4, 3, 2, 1, 0 };
+            ClipResults expectedResults = { 5.0f, 4.0f, 3.0f, 2.0f, 1.0f };
+
+            QTest::newRow("reverse")
+                    << rawClipResults << format << expectedResults;
+        }
+
+        {
+            ClipResults rawClipResults = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
+            ComponentIndices format = { 0, 1, -1, 3, 4 };
+            ClipResults expectedResults = { 1.0f, 2.0f, 0.0f, 4.0f, 5.0f };
+
+            QTest::newRow("include missing")
+                    << rawClipResults << format << expectedResults;
+        }
+    }
+
+    void checkFormatClipResults()
+    {
+        // GIVEN
+        QFETCH(ClipResults, rawClipResults);
+        QFETCH(ComponentIndices, format);
+        QFETCH(ClipResults, expectedResults);
+
+        // WHEN
+        const ClipResults actualResults = formatClipResults(rawClipResults, format);
+
+        // THEN
+        QCOMPARE(actualResults.size(), expectedResults.size());
+        for (int i = 0; i < actualResults.size(); ++i)
+            QCOMPARE(actualResults[i], expectedResults[i]);
+    }
 };
 
 QTEST_MAIN(tst_AnimationUtils)