Enable mercator-to-screen projection in GLSL

With this change, all the geo-to-screen conversion,
and the triangulation operations for geo polylines
and geo polygon are performed either at set time
or in the shader.
A separate bounding box geometry is processed
in the old way to provide a correct QtQuick Item
geometry, that can be used for nesting mouse areas,
performing translations, input event delivery, etc.

With this approach, performance are improved by more
than one order of magnitude in average, but complex
geometries will of course benefit more.

It also adds correct rendering support for polygons
with holes, previously only rendered correctly
by the MapboxGL plugin.

The polyline shader has basic miter joins. The miter is
skipped if the angle is too sharp to avoid complicating
the implementation.
This shader introduces some glitches when the polyline
is minified, for which the real fix is to
have LOD for the geometry, and render simplified
geometries at low zoom levels (added in a subsequent patch).

Note: this approach, at least in its current implementation,
does not support enabling layers on individual items, only
on the Map element.

Task-number: QTBUG-49303
Task-number: QTBUG-38459
Change-Id: I0c2dc0bf364d32f74ca7c4014f6d66e6219c8ae4
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

1 files changed, 416 insertions, 0 deletions

diff --git a/src/location/declarativemaps/qdeclarativerectanglemapitem_p_p.h b/src/location/declarativemaps/qdeclarativerectanglemapitem_p_p.h
new file mode 100644
index 00000000..520abdf3
--- /dev/null
+++ b/src/location/declarativemaps/qdeclarativerectanglemapitem_p_p.h
@@ -0,0 +1,416 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Paolo Angelelli <paolo.angelelli@gmail.com>
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtLocation module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QDECLARATIVERECTANGLEMAPITEM_P_P_H
+#define QDECLARATIVERECTANGLEMAPITEM_P_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtLocation/private/qlocationglobal_p.h>
+#include <QtLocation/private/qdeclarativepolygonmapitem_p_p.h>
+#include <QtLocation/private/qdeclarativerectanglemapitem_p.h>
+#include <QtPositioning/private/qwebmercator_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class Q_LOCATION_PRIVATE_EXPORT QDeclarativeRectangleMapItemPrivate
+{
+public:
+    QDeclarativeRectangleMapItemPrivate(QDeclarativeRectangleMapItem &rect) : m_rect(rect)
+    {
+
+    }
+    QDeclarativeRectangleMapItemPrivate(QDeclarativeRectangleMapItemPrivate &other) : m_rect(other.m_rect)
+    {
+    }
+
+    virtual ~QDeclarativeRectangleMapItemPrivate();
+    virtual void onLinePropertiesChanged() = 0;
+    virtual void markSourceDirtyAndUpdate() = 0;
+    virtual void onMapSet() = 0;
+    virtual void onGeoGeometryChanged() = 0;
+    virtual void onItemGeometryChanged() = 0;
+    virtual void updatePolish() = 0;
+    virtual void afterViewportChanged() = 0;
+    virtual QSGNode * updateMapItemPaintNode(QSGNode *oldNode, QQuickItem::UpdatePaintNodeData *data) = 0;
+    virtual bool contains(const QPointF &point) const = 0;
+
+    QDeclarativeRectangleMapItem &m_rect;
+};
+
+class Q_LOCATION_PRIVATE_EXPORT QDeclarativeRectangleMapItemPrivateCPU: public QDeclarativeRectangleMapItemPrivate
+{
+public:
+    QDeclarativeRectangleMapItemPrivateCPU(QDeclarativeRectangleMapItem &rect) : QDeclarativeRectangleMapItemPrivate(rect)
+    {
+    }
+
+    QDeclarativeRectangleMapItemPrivateCPU(QDeclarativeRectangleMapItemPrivate &other)
+    : QDeclarativeRectangleMapItemPrivate(other)
+    {
+    }
+
+    ~QDeclarativeRectangleMapItemPrivateCPU() override;
+
+    void onLinePropertiesChanged() override
+    {
+        // mark dirty just in case we're a width change
+        markSourceDirtyAndUpdate();
+    }
+    virtual void markSourceDirtyAndUpdate() override
+    {
+        m_geometry.markSourceDirty();
+        m_borderGeometry.markSourceDirty();
+        m_rect.polishAndUpdate();
+    }
+    virtual void onMapSet() override
+    {
+        markSourceDirtyAndUpdate();
+    }
+    virtual void onGeoGeometryChanged() override
+    {
+        markSourceDirtyAndUpdate();
+    }
+    virtual void onItemGeometryChanged() override
+    {
+        m_geometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        m_borderGeometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        markSourceDirtyAndUpdate();
+    }
+    virtual void afterViewportChanged() override
+    {
+        m_geometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        m_borderGeometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        markSourceDirtyAndUpdate();
+    }
+    virtual void updatePolish() override
+    {
+        if (!m_rect.topLeft().isValid() || !m_rect.bottomRight().isValid()) {
+            m_geometry.clear();
+            m_borderGeometry.clear();
+            m_rect.setWidth(0);
+            m_rect.setHeight(0);
+            return;
+        }
+
+        const QGeoProjectionWebMercator &p = static_cast<const QGeoProjectionWebMercator&>(m_rect.map()->geoProjection());
+
+        QScopedValueRollback<bool> rollback(m_rect.m_updatingGeometry);
+        m_rect.m_updatingGeometry = true;
+
+        const QList<QGeoCoordinate> perimeter = path(m_rect.m_rectangle);
+        const QList<QDoubleVector2D> pathMercator_ = pathMercator(perimeter);
+        m_geometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        m_geometry.updateSourcePoints(*m_rect.map(), pathMercator_);
+        m_geometry.updateScreenPoints(*m_rect.map(), m_rect.m_border.width());
+
+        QList<QGeoMapItemGeometry *> geoms;
+        geoms << &m_geometry;
+        m_borderGeometry.clear();
+
+        if (m_rect.m_border.color().alpha() != 0 && m_rect.m_border.width() > 0) {
+            QList<QDoubleVector2D> closedPath = pathMercator_;
+            closedPath << closedPath.first();
+
+            m_borderGeometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+            const QGeoCoordinate &geometryOrigin = m_geometry.origin();
+
+            m_borderGeometry.srcPoints_.clear();
+            m_borderGeometry.srcPointTypes_.clear();
+
+            QDoubleVector2D borderLeftBoundWrapped;
+            QList<QList<QDoubleVector2D > > clippedPaths = m_borderGeometry.clipPath(*m_rect.map(), closedPath, borderLeftBoundWrapped);
+            if (clippedPaths.size()) {
+                borderLeftBoundWrapped = p.geoToWrappedMapProjection(geometryOrigin);
+                m_borderGeometry.pathToScreen(*m_rect.map(), clippedPaths, borderLeftBoundWrapped);
+                m_borderGeometry.updateScreenPoints(*m_rect.map(), m_rect.m_border.width());
+
+                geoms << &m_borderGeometry;
+            } else {
+                m_borderGeometry.clear();
+            }
+        }
+
+        QRectF combined = QGeoMapItemGeometry::translateToCommonOrigin(geoms);
+        m_rect.setWidth(combined.width()  + 2 * m_rect.m_border.width()); // ToDo: fix this! 2 is incorrect
+        m_rect.setHeight(combined.height()  + 2 * m_rect.m_border.width());
+
+        m_rect.setPositionOnMap(m_geometry.origin(), m_geometry.firstPointOffset());
+    }
+
+    virtual QSGNode * updateMapItemPaintNode(QSGNode *oldNode, QQuickItem::UpdatePaintNodeData *data) override
+    {
+        Q_UNUSED(data);
+        if (!m_node || !oldNode) {
+            m_node = new MapPolygonNode();
+            if (oldNode) {
+                delete oldNode;
+                oldNode = nullptr;
+            }
+        } else {
+            m_node = static_cast<MapPolygonNode *>(oldNode);
+        }
+
+        //TODO: update only material
+        if (m_geometry.isScreenDirty() || m_borderGeometry.isScreenDirty() || m_rect.m_dirtyMaterial) {
+            m_node->update(m_rect.m_color, m_rect.m_border.color(), &m_geometry, &m_borderGeometry);
+            m_geometry.setPreserveGeometry(false);
+            m_borderGeometry.setPreserveGeometry(false);
+            m_geometry.markClean();
+            m_borderGeometry.markClean();
+            m_rect.m_dirtyMaterial = false;
+        }
+        return m_node;
+    }
+    virtual bool contains(const QPointF &point) const override
+    {
+        return (m_geometry.contains(point) || m_borderGeometry.contains(point));
+    }
+
+    static QList<QGeoCoordinate> path(const QGeoRectangle &rect)
+    {
+        QList<QGeoCoordinate> res;
+        res << rect.topLeft();
+        res << QGeoCoordinate(rect.topLeft().latitude(), rect.bottomRight().longitude());
+        res << rect.bottomRight();
+        res << QGeoCoordinate(rect.bottomRight().latitude(), rect.topLeft().longitude());
+        return res;
+    }
+
+    static QList<QGeoCoordinate> perimeter(const QGeoRectangle &rect)
+    {
+        QList<QGeoCoordinate> res;
+        res << rect.topLeft();
+        res << QGeoCoordinate(rect.topLeft().latitude(), rect.bottomRight().longitude());
+        res << rect.bottomRight();
+        res << QGeoCoordinate(rect.bottomRight().latitude(), rect.topLeft().longitude());
+        res << res.first();
+        return res;
+    }
+
+    static QList<QDoubleVector2D> pathMercator(const QList<QGeoCoordinate> &p)
+    {
+        QList<QDoubleVector2D> res;
+        for (const auto &c: p)
+            res << QWebMercator::coordToMercator(c);
+        return res;
+    }
+
+    QGeoMapPolygonGeometry m_geometry;
+    QGeoMapPolylineGeometry m_borderGeometry;
+    MapPolygonNode *m_node = nullptr;
+};
+
+class Q_LOCATION_PRIVATE_EXPORT QDeclarativeRectangleMapItemPrivateOpenGL: public QDeclarativeRectangleMapItemPrivate
+{
+public:
+    QDeclarativeRectangleMapItemPrivateOpenGL(QDeclarativeRectangleMapItem &rect) : QDeclarativeRectangleMapItemPrivate(rect)
+    {
+    }
+
+    QDeclarativeRectangleMapItemPrivateOpenGL(QDeclarativeRectangleMapItemPrivate &other)
+    : QDeclarativeRectangleMapItemPrivate(other)
+    {
+    }
+
+    ~QDeclarativeRectangleMapItemPrivateOpenGL() override;
+
+    void markScreenDirtyAndUpdate()
+    {
+        // preserveGeometry is cleared in updateMapItemPaintNode
+        m_geometry.markScreenDirty();
+        m_borderGeometry.markScreenDirty();
+        m_rect.polishAndUpdate();
+    }
+    void onLinePropertiesChanged() override
+    {
+        m_rect.m_dirtyMaterial = true;
+        afterViewportChanged();
+    }
+    virtual void markSourceDirtyAndUpdate() override
+    {
+        m_geometry.markSourceDirty();
+        m_borderGeometry.markSourceDirty();
+        m_rect.polishAndUpdate();
+    }
+    void preserveGeometry()
+    {
+        m_geometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+        m_borderGeometry.setPreserveGeometry(true, m_rect.m_rectangle.topLeft());
+    }
+    virtual void onMapSet() override
+    {
+        markSourceDirtyAndUpdate();
+    }
+    virtual void onGeoGeometryChanged() override
+    {
+        preserveGeometry();
+        markSourceDirtyAndUpdate();
+    }
+    virtual void onItemGeometryChanged() override
+    {
+        onGeoGeometryChanged();
+    }
+    virtual void afterViewportChanged() override
+    {
+        preserveGeometry();
+        markScreenDirtyAndUpdate();
+    }
+    virtual void updatePolish() override
+    {
+        if (!m_rect.topLeft().isValid() || !m_rect.bottomRight().isValid()) {
+            m_geometry.clear();
+            m_borderGeometry.clear();
+            m_rect.setWidth(0);
+            m_rect.setHeight(0);
+            return;
+        }
+
+        QScopedValueRollback<bool> rollback(m_rect.m_updatingGeometry);
+        m_rect.m_updatingGeometry = true;
+        const qreal lineWidth = m_rect.m_border.width();
+        const QColor &lineColor = m_rect.m_border.color();
+        const QColor &fillColor = m_rect.color();
+        if (fillColor.alpha() != 0) {
+            m_geometry.updateSourcePoints(*m_rect.map(), m_rect.m_rectangle);
+            m_geometry.markScreenDirty();
+            m_geometry.updateScreenPoints(*m_rect.map(), lineWidth, lineColor);
+        } else {
+            m_geometry.clearBounds();
+        }
+
+        QGeoMapItemGeometry * geom = &m_geometry;
+        m_borderGeometry.clearScreen();
+        if (lineColor.alpha() != 0 && lineWidth > 0) {
+            m_borderGeometry.updateSourcePoints(*m_rect.map(), m_rect.m_rectangle);
+            m_borderGeometry.markScreenDirty();
+            m_borderGeometry.updateScreenPoints(*m_rect.map(), lineWidth);
+            geom = &m_borderGeometry;
+        }
+        m_rect.setWidth(geom->sourceBoundingBox().width());
+        m_rect.setHeight(geom->sourceBoundingBox().height());
+        m_rect.setPosition(1.0 * geom->firstPointOffset() - QPointF(lineWidth * 0.5,lineWidth * 0.5));
+    }
+
+    virtual QSGNode * updateMapItemPaintNode(QSGNode *oldNode, QQuickItem::UpdatePaintNodeData *data) override
+    {
+        Q_UNUSED(data);
+
+        if (!m_rootNode || !oldNode) {
+            m_rootNode = new QDeclarativePolygonMapItemPrivateOpenGL::RootNode();
+            m_node = new MapPolygonNodeGL();
+            m_rootNode->appendChildNode(m_node);
+            m_polylinenode = new MapPolylineNodeOpenGLExtruded();
+            m_rootNode->appendChildNode(m_polylinenode);
+            m_rootNode->markDirty(QSGNode::DirtyNodeAdded);
+            if (oldNode)
+                delete oldNode;
+        } else {
+            m_rootNode = static_cast<QDeclarativePolygonMapItemPrivateOpenGL::RootNode *>(oldNode);
+        }
+
+        const QGeoMap *map = m_rect.map();
+        const QMatrix4x4 &combinedMatrix = map->geoProjection().qsgTransform();
+        const QDoubleVector3D &cameraCenter = map->geoProjection().centerMercator();
+
+        if (m_borderGeometry.isScreenDirty()) {
+            /* Do the border update first */
+            m_polylinenode->update(m_rect.m_border.color(),
+                                   float(m_rect.m_border.width()),
+                                   &m_borderGeometry,
+                                   combinedMatrix,
+                                   cameraCenter,
+                                   Qt::SquareCap,
+                                   true);
+            m_borderGeometry.setPreserveGeometry(false);
+            m_borderGeometry.markClean();
+        } else {
+            m_polylinenode->setSubtreeBlocked(true);
+        }
+        if (m_geometry.isScreenDirty()) {
+            m_node->update(m_rect.m_color,
+                         &m_geometry,
+                         combinedMatrix,
+                         cameraCenter);
+            m_geometry.setPreserveGeometry(false);
+            m_geometry.markClean();
+        } else {
+            m_node->setSubtreeBlocked(true);
+        }
+
+        m_rootNode->setSubtreeBlocked(false);
+        return m_rootNode;
+    }
+    virtual bool contains(const QPointF &point) const override
+    {
+        const qreal lineWidth = m_rect.m_border.width();
+        const QColor &lineColor = m_rect.m_border.color();
+        const QRectF &bounds = (lineColor.alpha() != 0 && lineWidth > 0) ? m_borderGeometry.sourceBoundingBox() : m_geometry.sourceBoundingBox();
+        if (bounds.contains(point)) {
+            QDeclarativeGeoMap *m = m_rect.quickMap();
+            if (m) {
+                const QGeoCoordinate crd = m->toCoordinate(m->mapFromItem(&m_rect, point));
+                return  m_rect.m_rectangle.contains(crd) || m_borderGeometry.contains(m_rect.mapToItem(m_rect.quickMap(), point),
+                                                                                      m_rect.border()->width(),
+                                                                                      static_cast<const QGeoProjectionWebMercator&>(m_rect.map()->geoProjection()));
+            } else {
+                return  true;
+            }
+        }
+        return false;
+    }
+
+    QGeoMapPolygonGeometryOpenGL m_geometry;
+    QGeoMapPolylineGeometryOpenGL m_borderGeometry;
+    QDeclarativePolygonMapItemPrivateOpenGL::RootNode *m_rootNode = nullptr;
+    MapPolygonNodeGL *m_node = nullptr;
+    MapPolylineNodeOpenGLExtruded *m_polylinenode = nullptr;
+};
+
+QT_END_NAMESPACE
+
+#endif // QDECLARATIVERECTANGLEMAPITEM_P_P_H
+