[ui] Viewer3D: TransformGizmo - drawing gizmo on top of the object

- Special entity acting as an object container: we can add the entities we want to control with a gizmo inside it.
- Drawing the gizmo always on top of the object to make sure to see it every time.

meshroom/ui/qml/Viewer3D/DefaultCameraController.qml

@@ -23,6 +23,8 @@ Entity {
     property alias windowSize: trackball.windowSize
     property alias trackballSize: trackball.trackballSize
 
+    property bool loseMouseFocus: false // Must be changed by other entities when they want to take mouse focus
+
     readonly property alias pressed: mouseHandler._pressed
     signal mousePressed(var mouse)
     signal mouseReleased(var mouse, var moved)
@@ -166,6 +168,8 @@ Entity {
     components: [
         FrameAction {
             onTriggered: {
+                if(loseMouseFocus) return
+
                 if(panning) { // translate
                     var d = (root.camera.viewCenter.minus(root.camera.position)).length() * 0.03;
                     var tx = axisMX.value * root.translateSpeed * d;

meshroom/ui/qml/Viewer3D/EntityWithGizmo.qml

@@ -0,0 +1,32 @@
+import Qt3D.Core 2.0
+import Qt3D.Render 2.9
+import Qt3D.Input 2.0
+import Qt3D.Extras 2.10
+import QtQuick 2.9
+import Qt3D.Logic 2.0
+
+Entity {
+    id: root
+    property DefaultCameraController cameraController
+    property Layer frontLayerComponent
+
+    readonly property Camera camera : cameraController.camera
+    readonly property var windowSize: cameraController.windowSize
+    readonly property alias objectTransform : transformGizmo.objectTransform // The Transform the object should use
+    
+    signal pickedChanged(bool pressed)
+
+    onPickedChanged: {
+        cameraController.loseMouseFocus = pressed // Notify the camera if the transform takes/releases the focus
+    }
+
+    TransformGizmo {
+        id: transformGizmo
+        camera: root.camera
+        windowSize: root.windowSize
+        frontLayerComponent: root.frontLayerComponent
+        onPickedChanged: {
+            root.pickedChanged(pressed)
+        }
+    }
+}

meshroom/ui/qml/Viewer3D/TransformGizmo.qml

@@ -7,14 +7,15 @@ import Qt3D.Logic 2.0
 
 Entity {
     id: root
-    property real gizmoScale: 0.20
+    property real gizmoScale: 0.15
     property Camera camera
     property var windowSize
+    property var frontLayerComponent
     readonly property Transform objectTransform : Transform {}
     
     signal pickedChanged(bool pressed)
 
-    components: [gizmoDisplayTransform, mouseHandler]
+    components: [gizmoDisplayTransform, mouseHandler, frontLayerComponent]
 
 
     /***** ENUMS *****/
@@ -194,7 +195,7 @@ Entity {
 
     Entity {
         id: centerSphereEntity
-        components: [centerSphereMesh, centerSphereMaterial]
+        components: [centerSphereMesh, centerSphereMaterial, frontLayerComponent]
 
         SphereMesh {
             id: centerSphereMesh
@@ -238,7 +239,7 @@ Entity {
 
                 Entity {
                     id: axisCylinder
-                    components: [cylinderMesh, cylinderTransform, scaleMaterial]
+                    components: [cylinderMesh, cylinderTransform, scaleMaterial, frontLayerComponent]
 
                     CylinderMesh {
                         id: cylinderMesh
@@ -275,7 +276,7 @@ Entity {
 
                 Entity {
                     id: axisScaleBox
-                    components: [cubeScaleMesh, cubeScaleTransform, scaleMaterial, scalePicker]
+                    components: [cubeScaleMesh, cubeScaleTransform, scaleMaterial, scalePicker, frontLayerComponent]
 
                     CuboidMesh {
                         id: cubeScaleMesh
@@ -334,7 +335,7 @@ Entity {
             // POSITION ENTITY
             Entity {
                 id: positionEntity
-                components: [coneMesh, coneTransform, positionMaterial, positionPicker]
+                components: [coneMesh, coneTransform, positionMaterial, positionPicker, frontLayerComponent]
 
                 ConeMesh {
                     id: coneMesh
@@ -394,7 +395,7 @@ Entity {
             // ROTATION ENTITY
             Entity {
                 id: rotationEntity
-                components: [torusMesh, torusTransform, rotationMaterial, rotationPicker]
+                components: [torusMesh, torusTransform, rotationMaterial, rotationPicker, frontLayerComponent]
 
                 TorusMesh {
                     id: torusMesh

meshroom/ui/qml/Viewer3D/Viewer3D.qml

@@ -207,6 +207,17 @@ FocusScope {
                                             ]
                                         }
                                     }
+                                    LayerFilter {
+                                        filterMode: LayerFilter.DiscardAnyMatchingLayers
+                                        layers: Layer {id: drawOnFront}
+                                    }
+                                    LayerFilter {
+                                        filterMode: LayerFilter.AcceptAnyMatchingLayers
+                                        layers: [drawOnFront]
+                                        RenderStateSet {
+                                            renderStates: DepthTest { depthFunction: DepthTest.Equal }
+                                        }
+                                    }
                                 }
                             }
                         }