Share the mesh in bigscene-cpp

No point loading the same data 1k times. Shaves 35% off the time from
application start to first frame being complete.

Change-Id: I8cd7c8a5aa377c0663c03e35d7a4c03f50b052f6
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

tests/manual/bigscene-cpp/entity.cpp

@@ -58,15 +58,8 @@
 Entity::Entity(Qt3DCore::QNode *parent)
     : QEntity(parent)
     , m_transform(new Qt3DCore::QTransform())
-    , m_mesh(new Qt3DExtras::QCylinderMesh())
     , m_material(new Qt3DExtras::QPhongMaterial())
 {
-    m_mesh->setRings(50.0f);
-    m_mesh->setSlices(30.0f);
-    m_mesh->setRadius(2.5f);
-    m_mesh->setLength(5.0f);
-
-    addComponent(m_mesh);
     addComponent(m_transform);
     addComponent(m_material);
 }

tests/manual/bigscene-cpp/entity.h

@@ -61,6 +61,10 @@ namespace Qt3DCore {
 class QTransform;
 }
 
+namespace Qt3DRender {
+class QGeometryRenderer;
+}
+
 namespace Qt3DExtras {
 class QCylinderMesh;
 class QPhongMaterial;
@@ -101,7 +105,6 @@ private:
 
 private:
     Qt3DCore::QTransform *m_transform;
-    Qt3DExtras::QCylinderMesh *m_mesh;
     Qt3DExtras::QPhongMaterial *m_material;
     float m_theta;
     float m_phi;

tests/manual/bigscene-cpp/main.cpp

@@ -81,6 +81,13 @@ int main(int ac, char **av)
 
     QEntity *root = new QEntity();
 
+    // Mesh
+    auto *mesh = new Qt3DExtras::QCylinderMesh(root);
+    mesh->setRings(50.0f);
+    mesh->setSlices(30.0f);
+    mesh->setRadius(2.5f);
+    mesh->setLength(5.0f);
+
     // Camera
     QCamera *cameraEntity = view.camera();
     cameraEntity->lens()->setPerspectiveProjection(45.0f, 16.0f/9.0f, 0.1f, 1000.0f);
@@ -99,6 +106,7 @@ int main(int ac, char **av)
     // Scene
     for (int i = 0; i < max; i++) {
         Entity *e = new Entity();
+        e->addComponent(mesh);
         const float angle = M_PI * 2.0f * i * det * 10.;
 
         e->setDiffuseColor(QColor(qFabs(qCos(angle)) * 255, 204, 75));