Generate default channel values as needed

Change-Id: I20871448ba10cf6459b156d00bebdf7a7c8a319b
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

4 files changed, 53 insertions, 5 deletions

diff --git a/src/animation/backend/animationutils_p.h b/src/animation/backend/animationutils_p.h
index 6a1b18936..8946eb755 100644
--- a/src/animation/backend/animationutils_p.h
+++ b/src/animation/backend/animationutils_p.h
@@ -191,6 +191,13 @@ inline QDebug operator<<(QDebug dbg, const ChannelNameAndType &nameAndType)
 }
 #endif
 
+struct ComponentValue
+{
+    int componentIndex;
+    float value;
+};
+QT3D_DECLARE_TYPEINFO_2(Qt3DAnimation, Animation, ComponentValue, Q_PRIMITIVE_TYPE)
+
 struct ClipFormat
 {
     // TODO: Remove the mask and store both the sourceClipIndices and
@@ -200,6 +207,7 @@ struct ClipFormat
     QVector<QBitArray> sourceClipMask;
     QVector<ComponentIndices> formattedComponentIndices;
     QVector<ChannelNameAndType> namesAndTypes;
+    QVector<ComponentValue> defaultComponentValues;
 };
 
 #ifndef QT_NO_DEBUG_STREAM
diff --git a/src/animation/backend/buildblendtreesjob.cpp b/src/animation/backend/buildblendtreesjob.cpp
index a08aa2a34..581b133b5 100644
--- a/src/animation/backend/buildblendtreesjob.cpp
+++ b/src/animation/backend/buildblendtreesjob.cpp
@@ -90,10 +90,17 @@ void BuildBlendTreesJob::run()
         QVector<QBitArray> blendTreeChannelMask;
         const QVector<Qt3DCore::QNodeId> valueNodeIds
                 = gatherValueNodesToEvaluate(m_handler, blendClipAnimator->blendTreeRootId());
+
+        // Store the clip value nodes to avoid further lookups below.
+        // TODO: Refactor this next block into a function in animationutils.cpp that takes
+        // a QVector<QClipBlendValue*> as input.
+        QVector<ClipBlendValue *> valueNodes;
+        valueNodes.reserve(valueNodeIds.size());
         for (const auto valueNodeId : valueNodeIds) {
             ClipBlendValue *valueNode
                     = static_cast<ClipBlendValue *>(m_handler->clipBlendNodeManager()->lookupNode(valueNodeId));
             Q_ASSERT(valueNode);
+            valueNodes.push_back(valueNode);
 
             const Qt3DCore::QNodeId clipId = valueNode->clipId();
             AnimationClip *clip = m_handler->animationClipLoaderManager()->lookupResource(clipId);
@@ -132,6 +139,34 @@ void BuildBlendTreesJob::run()
             }
         }
 
+        // Now that we know the overall blend tree mask, go back and compare this to
+        // the masks from each of the value nodes. If the overall mask requires a
+        // channel but the value node does not provide it, we need to store default
+        // values to use for that channel so that the blending evaluation works as
+        // expected.
+        for (const auto valueNode : valueNodes) {
+            ClipFormat &f = valueNode->clipFormat(blendClipAnimator->peerId());
+
+            const int channelCount = blendTreeChannelMask.size();
+            for (int i = 0; i < channelCount; ++i) {
+                if (blendTreeChannelMask[i] == f.sourceClipMask[i])
+                    continue; // Masks match, nothing to do
+
+                // If we get to here then we need to obtain a default value
+                // for this channel and store it for later application to any
+                // missing components of this channel.
+                const QVector<float> defaultValue = defaultValueForChannel(m_handler,
+                                                                           f.namesAndTypes[i]);
+
+                // Find the indices where we later need to inject these default
+                // values and store them in the format.
+                const ComponentIndices &componentIndices = f.formattedComponentIndices[i];
+                Q_ASSERT(componentIndices.size() == defaultValue.size());
+                for (int j = 0; j < defaultValue.size(); ++j)
+                    f.defaultComponentValues.push_back({componentIndices[j], defaultValue[j]});
+            }
+        }
+
         // Finally, build the mapping data vector for this blended clip animator. This
         // gets used during the final stage of evaluation when sending the property changes
         // out to the targets of the animation. We do the costly work once up front.
diff --git a/src/animation/backend/clipblendvalue.cpp b/src/animation/backend/clipblendvalue.cpp
index c1de1fea7..5685d5191 100644
--- a/src/animation/backend/clipblendvalue.cpp
+++ b/src/animation/backend/clipblendvalue.cpp
@@ -102,12 +102,16 @@ void ClipBlendValue::setClipFormat(Qt3DCore::QNodeId animatorId, const ClipForma
     }
 }
 
-ClipFormat ClipBlendValue::clipFormat(Qt3DCore::QNodeId animatorId)
+ClipFormat &ClipBlendValue::clipFormat(Qt3DCore::QNodeId animatorId)
 {
     const int animatorIndex = m_animatorIds.indexOf(animatorId);
-    if (animatorIndex != -1)
-        return m_clipFormats[animatorIndex];
-    return ClipFormat();
+    return m_clipFormats[animatorIndex];
+}
+
+const ClipFormat &ClipBlendValue::clipFormat(Qt3DCore::QNodeId animatorId) const
+{
+    const int animatorIndex = m_animatorIds.indexOf(animatorId);
+    return m_clipFormats[animatorIndex];
 }
 
 } // namespace Animation
diff --git a/src/animation/backend/clipblendvalue_p.h b/src/animation/backend/clipblendvalue_p.h
index 3e2987ed7..7b028583c 100644
--- a/src/animation/backend/clipblendvalue_p.h
+++ b/src/animation/backend/clipblendvalue_p.h
@@ -79,7 +79,8 @@ public:
     double duration() const Q_DECL_OVERRIDE;
 
     void setClipFormat(Qt3DCore::QNodeId animatorId, const ClipFormat &formatIndices);
-    ClipFormat clipFormat(Qt3DCore::QNodeId animatorId);
+    ClipFormat &clipFormat(Qt3DCore::QNodeId animatorId);
+    const ClipFormat &clipFormat(Qt3DCore::QNodeId animatorId) const;
 
 protected:
     ClipResults doBlend(const QVector<ClipResults> &blendData) const Q_DECL_OVERRIDE;