Copy core GL functionality to QtGui with QGL -> QOpenGL naming.

Change-Id: Ibc989afa4a30dd184d41d1a1cd89f97196e48855
Reviewed-on: http://codereview.qt.nokia.com/3710
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>

1 files changed, 175 insertions, 0 deletions

diff --git a/src/gui/opengl/qopengl2pexvertexarray.cpp b/src/gui/opengl/qopengl2pexvertexarray.cpp
new file mode 100644
index 0000000000..ec26fdbf5b
--- /dev/null
+++ b/src/gui/opengl/qopengl2pexvertexarray.cpp
@@ -0,0 +1,175 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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, Nokia gives you certain additional
+** rights. These rights are described in the Nokia 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.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qopengl2pexvertexarray_p.h"
+
+#include <private/qbezier_p.h>
+
+QT_BEGIN_NAMESPACE
+
+void QOpenGL2PEXVertexArray::clear()
+{
+    vertexArray.reset();
+    vertexArrayStops.reset();
+    boundingRectDirty = true;
+}
+
+
+QOpenGLRect QOpenGL2PEXVertexArray::boundingRect() const
+{
+    if (boundingRectDirty)
+        return QOpenGLRect(0.0, 0.0, 0.0, 0.0);
+    else
+        return QOpenGLRect(minX, minY, maxX, maxY);
+}
+
+void QOpenGL2PEXVertexArray::addClosingLine(int index)
+{
+    QPointF point(vertexArray.at(index));
+    if (point != QPointF(vertexArray.last()))
+        vertexArray.add(point);
+}
+
+void QOpenGL2PEXVertexArray::addCentroid(const QVectorPath &path, int subPathIndex)
+{
+    const QPointF *const points = reinterpret_cast<const QPointF *>(path.points());
+    const QPainterPath::ElementType *const elements = path.elements();
+
+    QPointF sum = points[subPathIndex];
+    int count = 1;
+
+    for (int i = subPathIndex + 1; i < path.elementCount() && (!elements || elements[i] != QPainterPath::MoveToElement); ++i) {
+        sum += points[i];
+        ++count;
+    }
+
+    const QPointF centroid = sum / qreal(count);
+    vertexArray.add(centroid);
+}
+
+void QOpenGL2PEXVertexArray::addPath(const QVectorPath &path, GLfloat curveInverseScale, bool outline)
+{
+    const QPointF* const points = reinterpret_cast<const QPointF*>(path.points());
+    const QPainterPath::ElementType* const elements = path.elements();
+
+    if (boundingRectDirty) {
+        minX = maxX = points[0].x();
+        minY = maxY = points[0].y();
+        boundingRectDirty = false;
+    }
+
+    if (!outline && !path.isConvex())
+        addCentroid(path, 0);
+
+    int lastMoveTo = vertexArray.size();
+    vertexArray.add(points[0]); // The first element is always a moveTo
+
+    do {
+        if (!elements) {
+//             qDebug("QVectorPath has no elements");
+            // If the path has a null elements pointer, the elements implicitly
+            // start with a moveTo (already added) and continue with lineTos:
+            for (int i=1; i<path.elementCount(); ++i)
+                lineToArray(points[i].x(), points[i].y());
+
+            break;
+        }
+//         qDebug("QVectorPath has element types");
+
+        for (int i=1; i<path.elementCount(); ++i) {
+            switch (elements[i]) {
+            case QPainterPath::MoveToElement:
+                if (!outline)
+                    addClosingLine(lastMoveTo);
+//                qDebug("element[%d] is a MoveToElement", i);
+                vertexArrayStops.add(vertexArray.size());
+                if (!outline) {
+                    if (!path.isConvex()) addCentroid(path, i);
+                    lastMoveTo = vertexArray.size();
+                }
+                lineToArray(points[i].x(), points[i].y()); // Add the moveTo as a new vertex
+                break;
+            case QPainterPath::LineToElement:
+//                qDebug("element[%d] is a LineToElement", i);
+                lineToArray(points[i].x(), points[i].y());
+                break;
+            case QPainterPath::CurveToElement: {
+                QBezier b = QBezier::fromPoints(*(((const QPointF *) points) + i - 1),
+                                                points[i],
+                                                points[i+1],
+                                                points[i+2]);
+                QRectF bounds = b.bounds();
+                // threshold based on same algorithm as in qtriangulatingstroker.cpp
+                int threshold = qMin<float>(64, qMax(bounds.width(), bounds.height()) * 3.14f / (curveInverseScale * 6));
+                if (threshold < 3) threshold = 3;
+                qreal one_over_threshold_minus_1 = qreal(1) / (threshold - 1);
+                for (int t=0; t<threshold; ++t) {
+                    QPointF pt = b.pointAt(t * one_over_threshold_minus_1);
+                    lineToArray(pt.x(), pt.y());
+                }
+                i += 2;
+                break; }
+            default:
+                break;
+            }
+        }
+    } while (0);
+
+    if (!outline)
+        addClosingLine(lastMoveTo);
+    vertexArrayStops.add(vertexArray.size());
+}
+
+void QOpenGL2PEXVertexArray::lineToArray(const GLfloat x, const GLfloat y)
+{
+    vertexArray.add(QOpenGLPoint(x, y));
+
+    if (x > maxX)
+        maxX = x;
+    else if (x < minX)
+        minX = x;
+    if (y > maxY)
+        maxY = y;
+    else if (y < minY)
+        minY = y;
+}
+
+QT_END_NAMESPACE