Add an example to exercise tessellation shader support

Also extended Renderer and friends to support setting the number
of vertices per patch with glPathParameteri(GL_PATCH_VERTICES, n).
To support this QMeshData now also stores the vertices per patch.

This demonstrates how to tessellate using quad tessellation mode.

Follow-up commits will add objects to show triangle and isoline
modes.

Change-Id: I68afb31815db430d0b4d8d9cc525efcfb9a216fc
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/examples/tessellation-modes/TessellatedWireframeMaterial.qml b/examples/tessellation-modes/TessellatedWireframeMaterial.qml
new file mode 100644
index 000000000..edd24795c
--- /dev/null
+++ b/examples/tessellation-modes/TessellatedWireframeMaterial.qml
@@ -0,0 +1,82 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 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 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import Qt3D 2.0
+import Qt3D.Render 2.0
+
+// For Qt.vector3d() and friends. For some reason this is provided by
+// QQuickValueTypeProvider in QtQuick rather than the default value
+// type provider in QtQml. So we will need to replicate this in Qt3D
+// for the types that we wish to support. Otherwise we'll have to import
+// QtQuick 2.1 all over the place.
+import QtQuick 2.1 as QQ2
+
+Material {
+    id: root
+
+    property color ambient: Qt.rgba( 0.05, 0.05, 0.05, 1.0 )
+    property color diffuse: Qt.rgba( 0.7, 0.7, 0.7, 1.0 )
+    property color specular: Qt.rgba( 0.95, 0.95, 0.95, 1.0 )
+    property real shininess: 150.0
+    property real lineWidth: 1.0
+    property color lineColor: Qt.rgba( 1.0, 1.0, 1.0, 1.0 )
+    property real innerTessLevel0: 1.0
+    property real innerTessLevel1: 1.0
+    property real outerTessLevel0: 1.0
+    property real outerTessLevel1: 1.0
+    property real outerTessLevel2: 1.0
+    property real outerTessLevel3: 1.0
+
+    parameters: [
+        Parameter { name: "ambient"; value: Qt.vector3d(root.ambient.r, root.ambient.g, root.ambient.b) },
+        Parameter { name: "diffuse"; value: Qt.vector3d(root.diffuse.r, root.diffuse.g, root.diffuse.b) },
+        Parameter { name: "specular"; value: Qt.vector3d(root.specular.r, root.specular.g, root.specular.b) },
+        Parameter { name: "shininess"; value: root.shininess },
+        Parameter { name: "line.width"; value: root.lineWidth },
+        Parameter { name: "line.color"; value: root.lineColor },
+        Parameter { name: "innerTessLevel0"; value: root.innerTessLevel0 },
+        Parameter { name: "innerTessLevel1"; value: root.innerTessLevel1 },
+        Parameter { name: "outerTessLevel0"; value: root.outerTessLevel0 },
+        Parameter { name: "outerTessLevel1"; value: root.outerTessLevel1 },
+        Parameter { name: "outerTessLevel2"; value: root.outerTessLevel2 },
+        Parameter { name: "outerTessLevel3"; value: root.outerTessLevel3 }
+    ]
+}