Technique: add a flag to check for compatibility

Will allow to avoid doing the expensive GraphicsApiFilterData comparison every
frame but only when the Technique has actually changed.

Change-Id: Ife4b6a03b7da5d157df33c7fc2770fea2d7b76fc
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 40 insertions, 0 deletions

diff --git a/src/render/materialsystem/technique.cpp b/src/render/materialsystem/technique.cpp
index a3a650f7a..bf141ad28 100644
--- a/src/render/materialsystem/technique.cpp
+++ b/src/render/materialsystem/technique.cpp
@@ -63,6 +63,7 @@ namespace Render {
 
 Technique::Technique()
     : BackendNode()
+    , m_isCompatibleWithRenderer(false)
 {
 }
 
@@ -77,6 +78,7 @@ void Technique::cleanup()
     m_parameterPack.clear();
     m_renderPasses.clear();
     m_filterKeyList.clear();
+    m_isCompatibleWithRenderer = false;
 }
 
 void Technique::initializeFromPeer(const Qt3DCore::QNodeCreatedChangeBasePtr &change)
@@ -98,6 +100,9 @@ void Technique::sceneChangeEvent(const Qt3DCore::QSceneChangePtr &e)
         if (change->propertyName() == QByteArrayLiteral("graphicsApiFilterData")) {
             GraphicsApiFilterData filterData = change->value().value<GraphicsApiFilterData>();
             m_graphicsApiFilterData = filterData;
+            // Notify the manager that our graphicsApiFilterData has changed
+            // and that we therefore need to be check for compatibility again
+            m_isCompatibleWithRenderer = false;
         }
         break;
     }
@@ -162,6 +167,16 @@ const GraphicsApiFilterData *Technique::graphicsApiFilter() const
     return &m_graphicsApiFilterData;
 }
 
+bool Technique::isCompatibleWithRenderer() const
+{
+    return m_isCompatibleWithRenderer;
+}
+
+void Technique::setCompatibleWithRenderer(bool compatible)
+{
+    m_isCompatibleWithRenderer = compatible;
+}
+
 void Technique::appendFilterKey(Qt3DCore::QNodeId criterionId)
 {
     if (!m_filterKeyList.contains(criterionId))
diff --git a/src/render/materialsystem/technique_p.h b/src/render/materialsystem/technique_p.h
index 9686495b9..61e27550a 100644
--- a/src/render/materialsystem/technique_p.h
+++ b/src/render/materialsystem/technique_p.h
@@ -93,6 +93,9 @@ public:
     QVector<Qt3DCore::QNodeId> renderPasses() const;
     const GraphicsApiFilterData *graphicsApiFilter() const;
 
+    bool isCompatibleWithRenderer() const;
+    void setCompatibleWithRenderer(bool compatible);
+
 private:
     void initializeFromPeer(const Qt3DCore::QNodeCreatedChangeBasePtr &change) Q_DECL_FINAL;
 
@@ -100,6 +103,7 @@ private:
     ParameterPack m_parameterPack;
     QVector<Qt3DCore::QNodeId> m_filterKeyList;
     QVector<Qt3DCore::QNodeId> m_renderPasses;
+    bool m_isCompatibleWithRenderer;
 };
 
 } // namespace Render
diff --git a/tests/auto/render/technique/tst_technique.cpp b/tests/auto/render/technique/tst_technique.cpp
index 06d560ee9..c5b8802ed 100644
--- a/tests/auto/render/technique/tst_technique.cpp
+++ b/tests/auto/render/technique/tst_technique.cpp
@@ -65,6 +65,7 @@ private Q_SLOTS:
         QCOMPARE(backendTechnique.parameters().size(), 0);
         QCOMPARE(backendTechnique.filterKeys().size(), 0);
         QCOMPARE(backendTechnique.renderPasses().size(), 0);
+        QCOMPARE(backendTechnique.isCompatibleWithRenderer(), false);
     }
 
     void checkCleanupState()
@@ -74,6 +75,7 @@ private Q_SLOTS:
 
         // WHEN
         backendTechnique.setEnabled(true);
+        backendTechnique.setCompatibleWithRenderer(true);
 
         {
             Qt3DRender::QTechnique technique;
@@ -95,6 +97,7 @@ private Q_SLOTS:
         QCOMPARE(backendTechnique.parameters().size(), 0);
         QCOMPARE(backendTechnique.filterKeys().size(), 0);
         QCOMPARE(backendTechnique.renderPasses().size(), 0);
+        QCOMPARE(backendTechnique.isCompatibleWithRenderer(), false);
     }
 
     void checkInitializeFromPeer()
@@ -125,6 +128,7 @@ private Q_SLOTS:
             QCOMPARE(backendTechnique.filterKeys().first(), filterKey.id());
             QCOMPARE(backendTechnique.renderPasses().size(), 1);
             QCOMPARE(backendTechnique.renderPasses().first(), pass.id());
+            QCOMPARE(backendTechnique.isCompatibleWithRenderer(), false);
         }
         {
             // WHEN
@@ -138,6 +142,21 @@ private Q_SLOTS:
         }
     }
 
+    void checkSetCompatibleWithRenderer()
+    {
+        // GIVEN
+        Qt3DRender::Render::Technique backendTechnique;
+
+        // THEN
+        QCOMPARE(backendTechnique.isCompatibleWithRenderer(), false);
+
+        // WHEN
+        backendTechnique.setCompatibleWithRenderer(true);
+
+        // THEN
+        QCOMPARE(backendTechnique.isCompatibleWithRenderer(), true);
+    }
+
     void checkSceneChangeEvents()
     {
         // GIVEN
@@ -158,6 +177,7 @@ private Q_SLOTS:
         }
         {
             // WHEN
+            backendTechnique.setCompatibleWithRenderer(true);
             Qt3DRender::GraphicsApiFilterData newValue;
             newValue.m_major = 4;
             newValue.m_minor = 5;
@@ -170,6 +190,7 @@ private Q_SLOTS:
 
             // THEN
             QCOMPARE(*backendTechnique.graphicsApiFilter(), newValue);
+            QCOMPARE(backendTechnique.isCompatibleWithRenderer(), false);
         }
         {
             Qt3DRender::QParameter parameter;