[ui] Viewer3D: Use directional light & add light controller

Use a single light entity instead of one per camera.
Use directional light instead of point light.
Add camera relative directional light controller.

Author: gregoire-dl

meshroom/ui/qml/Viewer3D/Inspector3D.qml

@@ -70,6 +70,12 @@ FloatingPane {
                         checked: Viewer3DSettings.displayOrigin
                         onClicked: Viewer3DSettings.displayOrigin = !Viewer3DSettings.displayOrigin
                     }
+                    MaterialToolButton {
+                        text: MaterialIcons.light_mode
+                        ToolTip.text: "Display Light Controller"
+                        checked: Viewer3DSettings.displayLightController
+                        onClicked: Viewer3DSettings.displayLightController = !Viewer3DSettings.displayLightController
+                    }
                 }
                 MaterialLabel {
                     text: MaterialIcons.grain

meshroom/ui/qml/Viewer3D/Viewer3D.qml

@@ -107,15 +107,6 @@ FocusScope {
                 upVector: defaultCamUpVector
                 viewCenter: defaultCamViewCenter
                 aspectRatio: width/height
-
-                // Scene light, attached to the camera
-                Entity {
-                    components: [
-                        PointLight {
-                            color: "white"
-                        }
-                    ]
-                }
             }
 
             ViewpointCamera {
@@ -125,6 +116,15 @@ FocusScope {
                 camera.aspectRatio: width/height
             }
 
+            Entity {
+                components: [
+                    DirectionalLight{
+                        color: "white"
+                        worldDirection: Transformations3DHelper.getRotatedCameraViewVector(cameraSelector.camera.viewVector, cameraSelector.camera.upVector, directionalLightPane.lightPitchValue, directionalLightPane.lightYawValue).normalized()
+                    }
+                ]
+            }
+
             TrackballGizmo {
                 beamRadius: 4.0/root.height
                 alpha: cameraController.moving ? 1.0 : 0.7
@@ -318,6 +318,17 @@ FocusScope {
         }
     }
 
+    // Directional light controller
+    DirectionalLightPane {
+        id: directionalLightPane
+        anchors {
+            bottom: parent.bottom
+            right: parent.right
+            margins: 2
+        }
+        visible: Viewer3DSettings.displayLightController
+    }
+
     // Menu
     Menu {
         id: contextMenu

meshroom/ui/qml/Viewer3D/Viewer3DSettings.qml

@@ -51,6 +51,7 @@ Item {
     property bool displayGrid: true
     property bool displayGizmo: true
     property bool displayOrigin: false
+    property bool displayLightController: false
     // Camera
     property bool syncViewpointCamera: false
     property bool syncWithPickedViewId: false  // Sync active camera with picked view ID from sequence player if the setting is enabled

meshroom/ui/qml/Viewer3D/ViewpointCamera.qml

@@ -16,15 +16,6 @@ Entity {
         nearPlane : 0.1
         farPlane : 10000.0
         viewCenter: Qt.vector3d(0.0, 0.0, -1.0)
-
-        // Scene light, attached to the camera
-        Entity {
-            components: [
-                PointLight {
-                    color: "white"
-                }
-            ]
-        }
     }
 
     components: [