QmlDesigner: Implement grid zooming

Grid zooms in and out according to camera zoom so that grid spacing is
neither too condense nor too sparse. Also changed the grid color to be
a bit darker and few other small tweaks.
PS: if the view camera is panned, the grid will not work correctly.
This is due to issues with the camera zoom calculations and is not part
of this commit.

Task-number: QDS-1566
Change-Id: Ib08d5387b028b8d870df9ecf88a5766eae5a509e
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

share/qtcreator/qml/qmlpuppet/mockfiles/EditView3D.qml

@@ -79,9 +79,11 @@ Window {
                                                   {"usePerspective": usePerspective,
                                                    "showSceneLight": showEditLight,
                                                    "importScene": activeScene,
+                                                   "cameraZoomFactor": cameraControl._zoomFactor,
                                                    "z": 1});
                 editView.usePerspective = Qt.binding(function() {return usePerspective;});
                 editView.showSceneLight = Qt.binding(function() {return showEditLight;});
+                editView.cameraZoomFactor = Qt.binding(function() {return cameraControl._zoomFactor;});
 
                 selectionBoxes.length = 0;
             }

share/qtcreator/qml/qmlpuppet/mockfiles/HelperGrid.qml

@@ -32,11 +32,13 @@ Node {
 
     property alias lines: gridGeometry.lines
     property alias step: gridGeometry.step
+    property alias subdivAlpha: subGridMaterial.opacity
 
     rotation.x: 90
 
     // Note: Only one instance of HelperGrid is supported, as the geometry names are fixed
-    Model {
+
+    Model { // Main grid lines
         geometry: GridGeometry {
             id: gridGeometry
             name: "3D Edit View Helper Grid"
@@ -45,13 +47,32 @@ Node {
         materials: [
             DefaultMaterial {
                 id: mainGridMaterial
-                emissiveColor: "#cccccc"
+                emissiveColor: "#aaaaaa"
                 lighting: DefaultMaterial.NoLighting
                 cullingMode: Material.DisableCulling
             }
         ]
     }
-    Model {
+
+    Model { // Subdivision lines
+        geometry: GridGeometry {
+            lines: gridGeometry.lines
+            step: gridGeometry.step
+            isSubdivision: true
+            name: "3D Edit View Helper Grid subdivisions"
+        }
+
+        materials: [
+            DefaultMaterial {
+                id: subGridMaterial
+                emissiveColor: mainGridMaterial.emissiveColor
+                lighting: DefaultMaterial.NoLighting
+                cullingMode: Material.DisableCulling
+            }
+        ]
+    }
+
+    Model { // Z Axis
         geometry: GridGeometry {
             lines: gridGeometry.lines
             step: gridGeometry.step
@@ -67,7 +88,7 @@ Node {
             }
         ]
     }
-    Model {
+    Model { // X Axis
         rotation.z: 90
         geometry: GridGeometry {
             lines: gridGeometry.lines

share/qtcreator/qml/qmlpuppet/mockfiles/SceneView3D.qml

@@ -35,16 +35,29 @@ View3D {
     property alias sceneHelpers: sceneHelpers
     property alias perpectiveCamera: scenePerspectiveCamera
     property alias orthoCamera: sceneOrthoCamera
+    property double cameraZoomFactor: .55;
+
+    // Empirical cameraZoomFactor values at which the grid zoom level is doubled. The values are
+    // approximately uniformally distributed over the non-linear range of cameraZoomFactor.
+    readonly property var grid_thresholds: [0.1, 0.265, 0.55, 1.10, 2.35, 4.9, 10.0, 20.5, 42.0, 85.0, 999999.0]
+    property var thresIdx: 1
+    property var thresPerc: 1.0 // percentage of cameraZoomFactor to the current grid zoom threshold (0.0 - 1.0)
 
     camera: usePerspective ? scenePerspectiveCamera : sceneOrthoCamera
 
+    onCameraZoomFactorChanged: {
+        thresIdx = Math.max(1, grid_thresholds.findIndex(v => v > cameraZoomFactor));
+        thresPerc = (grid_thresholds[thresIdx] - cameraZoomFactor) / (grid_thresholds[thresIdx] - grid_thresholds[thresIdx - 1]);
+    }
+
     Node {
         id: sceneHelpers
 
         HelperGrid {
             id: helperGrid
-            lines: 50
+            lines: 20 + Math.round((1 - thresPerc) * 20);
-            step: 50
+            step: 100 * grid_thresholds[0] * Math.pow(2, thresIdx - 1);
+            subdivAlpha: thresPerc;
         }
 
         PointLight {

share/qtcreator/qml/qmlpuppet/qml2puppet/editor3d/gridgeometry.cpp

@@ -114,16 +114,18 @@ QSSGRenderGraphObject *GridGeometry::updateSpatialNode(QSSGRenderGraphObject *no
 
 void GridGeometry::fillVertexData(QByteArray &vertexData)
 {
-    const int size = m_isCenterLine
+    const int numSubdivs = 1; // number of subdivision lines (i.e. lines between main grid lines)
-            ? int(sizeof(float)) * 3 * 2
+    const int vtxSize = int(sizeof(float)) * 3 * 2;
-            : 4 * m_lines * int(sizeof(float)) * 3 * 2;
+    const int size = m_isCenterLine ? vtxSize
+                  : m_isSubdivision ? 4 * m_lines * vtxSize * numSubdivs
+                                    : 4 * m_lines * vtxSize;
     vertexData.resize(size);
     float *dataPtr = reinterpret_cast<float *>(vertexData.data());
 
-    float y0 = -float(m_lines) * m_step;
     float x0 = -float(m_lines) * m_step;
-    float y1 = -y0;
+    float y0 = x0;
     float x1 = -x0;
+    float y1 = x1;
 
     if (m_isCenterLine) {
         // start position
@@ -134,6 +136,28 @@ void GridGeometry::fillVertexData(QByteArray &vertexData)
         dataPtr[3] = 0.f;
         dataPtr[4] = y1;
         dataPtr[5] = 0.f;
+    } else {
+        // Lines are created so that bounding box can later be calculated from first and last vertex
+        if (m_isSubdivision) {
+            const float subdivStep = m_step / float(numSubdivs + 1);
+            const int subdivMainLines = m_lines * 2;
+            auto generateSubLines = [&](float x0, float y0, float x1, float y1, bool vertical) {
+                for (int i = 0; i < subdivMainLines; ++i) {
+                    for (int j = 1; j <= numSubdivs; ++j) {
+                        // start position
+                        dataPtr[0] = vertical ? x0 + i * m_step + j * subdivStep : x0;
+                        dataPtr[1] = vertical ? y0 : y0 + i * m_step + j * subdivStep;
+                        dataPtr[2] = .0f;
+                        // end position
+                        dataPtr[3] = vertical ? x0 + i * m_step + j * subdivStep : x1;
+                        dataPtr[4] = vertical ? y1 : y0 + i * m_step + j * subdivStep;
+                        dataPtr[5] = .0f;
+                        dataPtr += 6;
+                    }
+                }
+            };
+            generateSubLines(x0, y0, x1, y1, true);
+            generateSubLines(x0, y0, x1, y1, false);
         } else {
             auto generateLines = [this, &dataPtr](float x0, float y0, float x1, float y1, bool vertical) {
                 for (int i = 0; i < m_lines; ++i) {
@@ -148,13 +172,12 @@ void GridGeometry::fillVertexData(QByteArray &vertexData)
                     dataPtr += 6;
                 }
             };
-
-        // Lines are created so that bounding box can later be calculated from first and last vertex
             generateLines(x0, y0, x1, y1, true);
             generateLines(x0, y0, x1, y1, false);
             generateLines(x0, m_step, x1, y1, false);
             generateLines(m_step, y0, x1, y1, true);
         }
+    }
 }
 
 }

share/qtcreator/qml/qmlpuppet/qml2puppet/editor3d/gridgeometry.h

@@ -35,9 +35,11 @@ namespace Internal {
 class GridGeometry : public QQuick3DGeometry
 {
     Q_OBJECT
+
     Q_PROPERTY(int lines READ lines WRITE setLines NOTIFY linesChanged)
     Q_PROPERTY(float step READ step WRITE setStep NOTIFY stepChanged)
     Q_PROPERTY(bool isCenterLine READ isCenterLine WRITE setIsCenterLine NOTIFY isCenterLineChanged)
+    Q_PROPERTY(bool isSubdivision MEMBER m_isSubdivision)
 
 public:
     GridGeometry();
@@ -63,9 +65,10 @@ protected:
 private:
     void fillVertexData(QByteArray &vertexData);
 
-    int m_lines = 1000;
+    int m_lines = 20; // number of lines on 1 side of an axis (so total number of grid lines in 1 direction = 2 * m_lines + 1)
     float m_step = .1f;
     bool m_isCenterLine = false;
+    bool m_isSubdivision = false;
 };
 
 }