From d055098540df99a5d426360e9322c659e678e5ee Mon Sep 17 00:00:00 2001
From: Paolo Angelelli <paolo.angelelli.qt@gmail.com>
Date: Wed, 27 Nov 2019 15:37:07 +0100
Subject: 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>
---
 .../location/geojson_viewer/GeoJsonDelegate.qml    | 12 +++++++----
 examples/location/geojson_viewer/main.qml          | 23 ++++++++++++++++++++--
 2 files changed, 29 insertions(+), 6 deletions(-)

(limited to 'examples')

diff --git a/examples/location/geojson_viewer/GeoJsonDelegate.qml b/examples/location/geojson_viewer/GeoJsonDelegate.qml
index ff0fbffa..afbafe95 100644
--- a/examples/location/geojson_viewer/GeoJsonDelegate.qml
+++ b/examples/location/geojson_viewer/GeoJsonDelegate.qml
@@ -51,14 +51,15 @@
 
 import QtQuick 2.12
 import QtPositioning 5.12
-import QtLocation 5.12
+import QtLocation 5.15
 import Qt.labs.qmlmodels 1.0
 
 DelegateChooser {
     id: dc
     role: "type"
     property color defaultColor: "grey"
-    property real defaultOpacity: 0.7
+    property real defaultOpacity: 0.6
+    property bool openGLBackends: false
 
     DelegateChoice {
         roleValue: "Point"
@@ -82,8 +83,9 @@ DelegateChooser {
         delegate: MapPolyline {
             property string geojsonType: "LineString"
             property var props: modelData.properties
+            backend: (dc.openGLBackends) ? MapPolyline.OpenGLExtruded : MapPolyline.Software
             geoShape: modelData.data
-            line.width: 3
+            line.width: 4
             opacity: dc.defaultOpacity
             line.color: (props && props.color) || (parent && parent.props && parent.props.color) || dc.defaultColor
         }
@@ -97,7 +99,9 @@ DelegateChooser {
             geoShape: modelData.data
             opacity: dc.defaultOpacity
             color: (props && props.color) || (parent && parent.props && parent.props.color) || dc.defaultColor
-            border.width: 0
+            border.width: 4
+            border.color: 'black'
+            backend: (dc.openGLBackends) ? MapPolygon.OpenGL : MapPolygon.Software
             MouseArea {
                 anchors.fill: parent
                 onClicked: {
diff --git a/examples/location/geojson_viewer/main.qml b/examples/location/geojson_viewer/main.qml
index 01faef5f..b2fc3524 100644
--- a/examples/location/geojson_viewer/main.qml
+++ b/examples/location/geojson_viewer/main.qml
@@ -61,11 +61,13 @@ import Qt.labs.qmlmodels 1.0
 import Qt.GeoJson 1.0
 
 C1.ApplicationWindow {
+    id: win
     visible: true
     width: 1024
     height: 1024
     menuBar: mainMenu
     title: qsTr("GeoJSON Viewer")
+    property bool openGLBackends: glBackendSelector.checked
 
     FileDialog {
         visible: false
@@ -141,6 +143,12 @@ C1.ApplicationWindow {
                     geoJsoner.print(miv)
                 }
             }
+            C1.MenuItem {
+                text: "&OpenGL Item backends"
+                id: glBackendSelector
+                checkable: true
+                checked: false
+            }
         }
 
     }
@@ -149,17 +157,28 @@ C1.ApplicationWindow {
         id: geoJsoner
     }
 
+    Shortcut {
+        sequence: "Ctrl+P"
+        onActivated: {
+
+            console.log("Center : QtPositioning.coordinate(",map.center.latitude,",",map.center.longitude,")")
+            console.log("Zoom   : ",map.zoomLevel)
+        }
+    }
+
     Map {
         id: map
         anchors.fill: parent
         center: QtPositioning.coordinate(43.59, 13.50) // Starting coordinates: Ancona, the city where I am studying :)
-        plugin: Plugin { name: "mapboxgl" }
+        plugin: Plugin { name: "osm" }
         zoomLevel: 4
 
         MapItemView {
             id: miv
             model: geoJsoner.model
-            delegate: GeoJsonDelegate {}
+            delegate: GeoJsonDelegate {
+                openGLBackends: win.openGLBackends
+            }
         }
     }
 }
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