Add cross-backend simple rect, texture, and ninepatch nodes

QSGSimpleRectNode is deprecated -> use
QSGRectangleNode via QQuickWindow::createRectangleNode() instead.

QSGSimpleTextureNode is deprecated -> use
QSGImageNode via QQuickWindow::createImageNode() instead.

The OpenGL version of the simple rectangle node is switched over to
the vertex color material instead of flat, to allow for better batching.

Use the same concept for nine patch nodes. The "style" node from Quick Controls 1
is now QSGNinePatchNode in order to provide a proper cross-backend solution which
is already necessary due to the software backend, but now generalize it to apply
to the accelerated backends with proper materials as well. QC can now simply call
createNinePatchNode() without further ado.

Also fixes a bug with the D3D12 texture material not enabling blending
when needed.

When it comes to the internal class names, QSGRectangleNode and
QSGImageNode get the Internal prefix in the adaptation layer in order to
differentiate from the public API. This involves quite a lot of renaming,
but results in a nice and clean public API.

Change-Id: Iddf9f9412377843ea6d652bcf25e68d1d74659ea
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 687 insertions, 0 deletions

diff --git a/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp b/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp
new file mode 100644
index 0000000000..8fc850b60c
--- /dev/null
+++ b/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp
@@ -0,0 +1,687 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://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.LGPL3 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-3.0.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 (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qsgbasicinternalrectanglenode_p.h"
+
+#include <QtCore/qmath.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace
+{
+    struct Color4ub
+    {
+        unsigned char r, g, b, a;
+    };
+
+    Color4ub operator *(Color4ub c, float t) { c.a *= t; c.r *= t; c.g *= t; c.b *= t; return c; }
+    Color4ub operator +(Color4ub a, Color4ub b) {  a.a += b.a; a.r += b.r; a.g += b.g; a.b += b.b; return a; }
+
+    inline Color4ub colorToColor4ub(const QColor &c)
+    {
+        Color4ub color = { uchar(qRound(c.redF() * c.alphaF() * 255)),
+                           uchar(qRound(c.greenF() * c.alphaF() * 255)),
+                           uchar(qRound(c.blueF() * c.alphaF() * 255)),
+                           uchar(qRound(c.alphaF() * 255))
+                         };
+        return color;
+    }
+
+    // Same layout as QSGGeometry::ColoredPoint2D, but uses Color4ub for convenience.
+    struct Vertex
+    {
+        float x, y;
+        Color4ub color;
+        void set(float nx, float ny, Color4ub ncolor)
+        {
+            x = nx; y = ny; color = ncolor;
+        }
+    };
+
+    struct SmoothVertex : public Vertex
+    {
+        float dx, dy;
+        void set(float nx, float ny, Color4ub ncolor, float ndx, float ndy)
+        {
+            Vertex::set(nx, ny, ncolor);
+            dx = ndx; dy = ndy;
+        }
+    };
+
+    const QSGGeometry::AttributeSet &smoothAttributeSet()
+    {
+        static QSGGeometry::Attribute data[] = {
+            QSGGeometry::Attribute::createWithSemantic(0, 2, QSGGeometry::TypeFloat, QSGGeometry::Attribute::POSITION),
+            QSGGeometry::Attribute::createWithSemantic(1, 4, QSGGeometry::TypeUnsignedByte, QSGGeometry::Attribute::COLOR),
+            QSGGeometry::Attribute::createWithSemantic(2, 2, QSGGeometry::TypeFloat, QSGGeometry::Attribute::TEXCOORD)
+        };
+        static QSGGeometry::AttributeSet attrs = { 3, sizeof(SmoothVertex), data };
+        return attrs;
+    }
+}
+
+QSGBasicInternalRectangleNode::QSGBasicInternalRectangleNode()
+    : m_radius(0)
+    , m_pen_width(0)
+    , m_aligned(true)
+    , m_antialiasing(false)
+    , m_gradient_is_opaque(true)
+    , m_dirty_geometry(false)
+    , m_geometry(QSGGeometry::defaultAttributes_ColoredPoint2D(), 0)
+{
+    setGeometry(&m_geometry);
+
+#ifdef QSG_RUNTIME_DESCRIPTION
+    qsgnode_set_description(this, QLatin1String("internalrectangle"));
+#endif
+}
+
+void QSGBasicInternalRectangleNode::setRect(const QRectF &rect)
+{
+    if (rect == m_rect)
+        return;
+    m_rect = rect;
+    m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setColor(const QColor &color)
+{
+    if (color == m_color)
+        return;
+    m_color = color;
+    if (m_gradient_stops.isEmpty())
+        m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setPenColor(const QColor &color)
+{
+    if (color == m_border_color)
+        return;
+    m_border_color = color;
+    if (m_pen_width > 0)
+        m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setPenWidth(qreal width)
+{
+    if (width == m_pen_width)
+        return;
+    m_pen_width = width;
+    m_dirty_geometry = true;
+}
+
+
+void QSGBasicInternalRectangleNode::setGradientStops(const QGradientStops &stops)
+{
+    if (stops.constData() == m_gradient_stops.constData())
+        return;
+
+    m_gradient_stops = stops;
+
+    m_gradient_is_opaque = true;
+    for (int i = 0; i < stops.size(); ++i)
+        m_gradient_is_opaque &= stops.at(i).second.alpha() == 0xff;
+    m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setRadius(qreal radius)
+{
+    if (radius == m_radius)
+        return;
+    m_radius = radius;
+    m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setAntialiasing(bool antialiasing)
+{
+    if (!supportsAntialiasing())
+        return;
+
+    if (antialiasing == m_antialiasing)
+        return;
+    m_antialiasing = antialiasing;
+    if (m_antialiasing) {
+        setGeometry(new QSGGeometry(smoothAttributeSet(), 0));
+        setFlag(OwnsGeometry, true);
+    } else {
+        setGeometry(&m_geometry);
+        setFlag(OwnsGeometry, false);
+    }
+    updateMaterialAntialiasing();
+    m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::setAligned(bool aligned)
+{
+    if (aligned == m_aligned)
+        return;
+    m_aligned = aligned;
+    m_dirty_geometry = true;
+}
+
+void QSGBasicInternalRectangleNode::update()
+{
+    if (m_dirty_geometry) {
+        updateGeometry();
+        m_dirty_geometry = false;
+
+        QSGNode::DirtyState state = QSGNode::DirtyGeometry;
+        updateMaterialBlending(&state);
+        markDirty(state);
+    }
+}
+
+void QSGBasicInternalRectangleNode::updateGeometry()
+{
+    float width = float(m_rect.width());
+    float height = float(m_rect.height());
+    float penWidth = qMin(qMin(width, height) * 0.5f, float(m_pen_width));
+
+    if (m_aligned)
+        penWidth = qRound(penWidth);
+
+    QSGGeometry *g = geometry();
+    g->setDrawingMode(QSGGeometry::DrawTriangleStrip);
+    int vertexStride = g->sizeOfVertex();
+
+    union {
+        Vertex *vertices;
+        SmoothVertex *smoothVertices;
+    };
+
+    Color4ub fillColor = colorToColor4ub(m_color);
+    Color4ub borderColor = colorToColor4ub(m_border_color);
+    Color4ub transparent = { 0, 0, 0, 0 };
+    const QGradientStops &stops = m_gradient_stops;
+
+    int nextGradientStop = 0;
+    float gradientPos = penWidth / height;
+    while (nextGradientStop < stops.size() && stops.at(nextGradientStop).first <= gradientPos)
+        ++nextGradientStop;
+    int lastGradientStop = stops.size() - 1;
+    float lastGradientPos = 1.0f - penWidth / height;
+    while (lastGradientStop >= nextGradientStop && stops.at(lastGradientStop).first >= lastGradientPos)
+        --lastGradientStop;
+    int gradientIntersections = (lastGradientStop - nextGradientStop + 1);
+
+    if (m_radius > 0) {
+        // Rounded corners.
+
+        // Radius should never exceeds half of the width or half of the height
+        float radius = qMin(qMin(width, height) * 0.5f, float(m_radius));
+        QRectF innerRect = m_rect;
+        innerRect.adjust(radius, radius, -radius, -radius);
+
+        float innerRadius = radius - penWidth * 1.0f;
+        float outerRadius = radius;
+        float delta = qMin(width, height) * 0.5f;
+
+        // Number of segments per corner, approximately one per 3 pixels.
+        int segments = qBound(3, qCeil(outerRadius * (M_PI / 6)), 18);
+
+        /*
+
+        --+--__
+        --+--__--__
+          |    --__--__
+          |  seg   --__--+
+        --+-__  ment  _+  \
+        --+-__--__   -  \  \
+              --__--+ se \  \
+                  +  \  g \  \
+                   \  \  m \  \
+         -----------+--+  e \  \     <- gradient line
+                     \  \  nt\  \
+           fill       +--+----+--+
+                      |  |    |  |
+                         border
+                  inner AA    outer AA (AA = antialiasing)
+
+        */
+
+        int innerVertexCount = (segments + 1) * 4 + gradientIntersections * 2;
+        int outerVertexCount = (segments + 1) * 4;
+        int vertexCount = innerVertexCount;
+        if (m_antialiasing || penWidth)
+            vertexCount += innerVertexCount;
+        if (penWidth)
+            vertexCount += outerVertexCount;
+        if (m_antialiasing && penWidth)
+            vertexCount += outerVertexCount;
+
+        int fillIndexCount = innerVertexCount;
+        int innerAAIndexCount = innerVertexCount * 2 + 2;
+        int borderIndexCount = innerVertexCount * 2 + 2;
+        int outerAAIndexCount = outerVertexCount * 2 + 2;
+        int indexCount = 0;
+        int fillHead = 0;
+        int innerAAHead = 0;
+        int innerAATail = 0;
+        int borderHead = 0;
+        int borderTail = 0;
+        int outerAAHead = 0;
+        int outerAATail = 0;
+        bool hasFill = m_color.alpha() > 0 || !stops.isEmpty();
+        if (hasFill)
+            indexCount += fillIndexCount;
+        if (m_antialiasing) {
+            innerAATail = innerAAHead = indexCount + (innerAAIndexCount >> 1) + 1;
+            indexCount += innerAAIndexCount;
+        }
+        if (penWidth) {
+            borderTail = borderHead = indexCount + (borderIndexCount >> 1) + 1;
+            indexCount += borderIndexCount;
+        }
+        if (m_antialiasing && penWidth) {
+            outerAATail = outerAAHead = indexCount + (outerAAIndexCount >> 1) + 1;
+            indexCount += outerAAIndexCount;
+        }
+
+        g->allocate(vertexCount, indexCount);
+        vertices = reinterpret_cast<Vertex *>(g->vertexData());
+        memset(vertices, 0, vertexCount * vertexStride);
+        quint16 *indices = g->indexDataAsUShort();
+        quint16 index = 0;
+
+        float py = 0; // previous inner y-coordinate.
+        float plx = 0; // previous inner left x-coordinate.
+        float prx = 0; // previous inner right x-coordinate.
+
+        float angle = 0.5f * float(M_PI) / segments;
+        float cosStep = qFastCos(angle);
+        float sinStep = qFastSin(angle);
+
+        for (int part = 0; part < 2; ++part) {
+            float c = 1 - part;
+            float s = part;
+            for (int i = 0; i <= segments; ++i) {
+                float y, lx, rx;
+                if (innerRadius > 0) {
+                    y = (part ? innerRect.bottom() : innerRect.top()) - innerRadius * c; // current inner y-coordinate.
+                    lx = innerRect.left() - innerRadius * s; // current inner left x-coordinate.
+                    rx = innerRect.right() + innerRadius * s; // current inner right x-coordinate.
+                    gradientPos = ((part ? innerRect.height() : 0) + radius - innerRadius * c) / height;
+                } else {
+                    y = (part ? innerRect.bottom() + innerRadius : innerRect.top() - innerRadius); // current inner y-coordinate.
+                    lx = innerRect.left() - innerRadius; // current inner left x-coordinate.
+                    rx = innerRect.right() + innerRadius; // current inner right x-coordinate.
+                    gradientPos = ((part ? innerRect.height() + innerRadius : -innerRadius) + radius) / height;
+                }
+                float Y = (part ? innerRect.bottom() : innerRect.top()) - outerRadius * c; // current outer y-coordinate.
+                float lX = innerRect.left() - outerRadius * s; // current outer left x-coordinate.
+                float rX = innerRect.right() + outerRadius * s; // current outer right x-coordinate.
+
+                while (nextGradientStop <= lastGradientStop && stops.at(nextGradientStop).first <= gradientPos) {
+                    // Insert vertices at gradient stops.
+                    float gy = (innerRect.top() - radius) + stops.at(nextGradientStop).first * height;
+                    float t = (gy - py) / (y - py);
+                    float glx = plx * (1 - t) + t * lx;
+                    float grx = prx * (1 - t) + t * rx;
+
+                    fillColor = colorToColor4ub(stops.at(nextGradientStop).second);
+
+                    if (hasFill) {
+                        indices[fillHead++] = index;
+                        indices[fillHead++] = index + 1;
+                    }
+
+                    if (penWidth) {
+                        --borderHead;
+                        indices[borderHead] = indices[borderHead + 2];
+                        indices[--borderHead] = index + 2;
+                        indices[borderTail++] = index + 3;
+                        indices[borderTail] = indices[borderTail - 2];
+                        ++borderTail;
+                    }
+
+                    if (m_antialiasing) {
+                        indices[--innerAAHead] = index + 2;
+                        indices[--innerAAHead] = index;
+                        indices[innerAATail++] = index + 1;
+                        indices[innerAATail++] = index + 3;
+
+                        bool lower = stops.at(nextGradientStop).first > 0.5f;
+                        float dy = lower ? qMin(0.0f, height - gy - delta) : qMax(0.0f, delta - gy);
+                        smoothVertices[index++].set(grx, gy, fillColor, width - grx - delta, dy);
+                        smoothVertices[index++].set(glx, gy, fillColor, delta - glx, dy);
+                        if (penWidth) {
+                            smoothVertices[index++].set(grx, gy, borderColor, 0.49f * penWidth * s, -0.49f * penWidth * c);
+                            smoothVertices[index++].set(glx, gy, borderColor, -0.49f * penWidth * s, -0.49f * penWidth * c);
+                        } else {
+                            dy = lower ? delta : -delta;
+                            smoothVertices[index++].set(grx, gy, transparent, delta, dy);
+                            smoothVertices[index++].set(glx, gy, transparent, -delta, dy);
+                        }
+                    } else {
+                        vertices[index++].set(grx, gy, fillColor);
+                        vertices[index++].set(glx, gy, fillColor);
+                        if (penWidth) {
+                            vertices[index++].set(grx, gy, borderColor);
+                            vertices[index++].set(glx, gy, borderColor);
+                        }
+                    }
+                    ++nextGradientStop;
+                }
+
+                if (!stops.isEmpty()) {
+                    if (nextGradientStop == 0) {
+                        fillColor = colorToColor4ub(stops.at(0).second);
+                    } else if (nextGradientStop == stops.size()) {
+                        fillColor = colorToColor4ub(stops.last().second);
+                    } else {
+                        const QGradientStop &prev = stops.at(nextGradientStop - 1);
+                        const QGradientStop &next = stops.at(nextGradientStop);
+                        float t = (gradientPos - prev.first) / (next.first - prev.first);
+                        fillColor = colorToColor4ub(prev.second) * (1 - t) + colorToColor4ub(next.second) * t;
+                    }
+                }
+
+                if (hasFill) {
+                    indices[fillHead++] = index;
+                    indices[fillHead++] = index + 1;
+                }
+
+                if (penWidth) {
+                    indices[--borderHead] = index + 4;
+                    indices[--borderHead] = index + 2;
+                    indices[borderTail++] = index + 3;
+                    indices[borderTail++] = index + 5;
+                }
+
+                if (m_antialiasing) {
+                    indices[--innerAAHead] = index + 2;
+                    indices[--innerAAHead] = index;
+                    indices[innerAATail++] = index + 1;
+                    indices[innerAATail++] = index + 3;
+
+                    float dy = part ? qMin(0.0f, height - y - delta) : qMax(0.0f, delta - y);
+                    smoothVertices[index++].set(rx, y, fillColor, width - rx - delta, dy);
+                    smoothVertices[index++].set(lx, y, fillColor, delta - lx, dy);
+
+                    dy = part ? delta : -delta;
+                    if (penWidth) {
+                        smoothVertices[index++].set(rx, y, borderColor, 0.49f * penWidth * s, -0.49f * penWidth * c);
+                        smoothVertices[index++].set(lx, y, borderColor, -0.49f * penWidth * s, -0.49f * penWidth * c);
+                        smoothVertices[index++].set(rX, Y, borderColor, -0.49f * penWidth * s, 0.49f * penWidth * c);
+                        smoothVertices[index++].set(lX, Y, borderColor, 0.49f * penWidth * s, 0.49f * penWidth * c);
+                        smoothVertices[index++].set(rX, Y, transparent, delta, dy);
+                        smoothVertices[index++].set(lX, Y, transparent, -delta, dy);
+
+                        indices[--outerAAHead] = index - 2;
+                        indices[--outerAAHead] = index - 4;
+                        indices[outerAATail++] = index - 3;
+                        indices[outerAATail++] = index - 1;
+                    } else {
+                        smoothVertices[index++].set(rx, y, transparent, delta, dy);
+                        smoothVertices[index++].set(lx, y, transparent, -delta, dy);
+                    }
+                } else {
+                    vertices[index++].set(rx, y, fillColor);
+                    vertices[index++].set(lx, y, fillColor);
+                    if (penWidth) {
+                        vertices[index++].set(rx, y, borderColor);
+                        vertices[index++].set(lx, y, borderColor);
+                        vertices[index++].set(rX, Y, borderColor);
+                        vertices[index++].set(lX, Y, borderColor);
+                    }
+                }
+
+                py = y;
+                plx = lx;
+                prx = rx;
+
+                // Rotate
+                qreal tmp = c;
+                c = c * cosStep - s * sinStep;
+                s = s * cosStep + tmp * sinStep;
+            }
+        }
+        Q_ASSERT(index == vertexCount);
+
+        // Close the triangle strips.
+        if (m_antialiasing) {
+            indices[--innerAAHead] = indices[innerAATail - 1];
+            indices[--innerAAHead] = indices[innerAATail - 2];
+            Q_ASSERT(innerAATail <= indexCount);
+        }
+        if (penWidth) {
+            indices[--borderHead] = indices[borderTail - 1];
+            indices[--borderHead] = indices[borderTail - 2];
+            Q_ASSERT(borderTail <= indexCount);
+        }
+        if (m_antialiasing && penWidth) {
+            indices[--outerAAHead] = indices[outerAATail - 1];
+            indices[--outerAAHead] = indices[outerAATail - 2];
+            Q_ASSERT(outerAATail == indexCount);
+        }
+    } else {
+        // Straight corners.
+        QRectF innerRect = m_rect;
+        QRectF outerRect = m_rect;
+
+        if (penWidth)
+            innerRect.adjust(1.0f * penWidth, 1.0f * penWidth, -1.0f * penWidth, -1.0f * penWidth);
+
+        float delta = qMin(width, height) * 0.5f;
+        int innerVertexCount = 4 + gradientIntersections * 2;
+        int outerVertexCount = 4;
+        int vertexCount = innerVertexCount;
+        if (m_antialiasing || penWidth)
+            vertexCount += innerVertexCount;
+        if (penWidth)
+            vertexCount += outerVertexCount;
+        if (m_antialiasing && penWidth)
+            vertexCount += outerVertexCount;
+
+        int fillIndexCount = innerVertexCount;
+        int innerAAIndexCount = innerVertexCount * 2 + 2;
+        int borderIndexCount = innerVertexCount * 2 + 2;
+        int outerAAIndexCount = outerVertexCount * 2 + 2;
+        int indexCount = 0;
+        int fillHead = 0;
+        int innerAAHead = 0;
+        int innerAATail = 0;
+        int borderHead = 0;
+        int borderTail = 0;
+        int outerAAHead = 0;
+        int outerAATail = 0;
+        bool hasFill = m_color.alpha() > 0 || !stops.isEmpty();
+        if (hasFill)
+            indexCount += fillIndexCount;
+        if (m_antialiasing) {
+            innerAATail = innerAAHead = indexCount + (innerAAIndexCount >> 1) + 1;
+            indexCount += innerAAIndexCount;
+        }
+        if (penWidth) {
+            borderTail = borderHead = indexCount + (borderIndexCount >> 1) + 1;
+            indexCount += borderIndexCount;
+        }
+        if (m_antialiasing && penWidth) {
+            outerAATail = outerAAHead = indexCount + (outerAAIndexCount >> 1) + 1;
+            indexCount += outerAAIndexCount;
+        }
+
+        g->allocate(vertexCount, indexCount);
+        vertices = reinterpret_cast<Vertex *>(g->vertexData());
+        memset(vertices, 0, vertexCount * vertexStride);
+        quint16 *indices = g->indexDataAsUShort();
+        quint16 index = 0;
+
+        float lx = innerRect.left();
+        float rx = innerRect.right();
+        float lX = outerRect.left();
+        float rX = outerRect.right();
+
+        for (int part = -1; part <= 1; part += 2) {
+            float y = (part == 1 ? innerRect.bottom() : innerRect.top());
+            float Y = (part == 1 ? outerRect.bottom() : outerRect.top());
+            gradientPos = (y - innerRect.top() + penWidth) / height;
+
+            while (nextGradientStop <= lastGradientStop && stops.at(nextGradientStop).first <= gradientPos) {
+                // Insert vertices at gradient stops.
+                float gy = (innerRect.top() - penWidth) + stops.at(nextGradientStop).first * height;
+
+                fillColor = colorToColor4ub(stops.at(nextGradientStop).second);
+
+                if (hasFill) {
+                    indices[fillHead++] = index;
+                    indices[fillHead++] = index + 1;
+                }
+
+                if (penWidth) {
+                    --borderHead;
+                    indices[borderHead] = indices[borderHead + 2];
+                    indices[--borderHead] = index + 2;
+                    indices[borderTail++] = index + 3;
+                    indices[borderTail] = indices[borderTail - 2];
+                    ++borderTail;
+                }
+
+                if (m_antialiasing) {
+                    indices[--innerAAHead] = index + 2;
+                    indices[--innerAAHead] = index;
+                    indices[innerAATail++] = index + 1;
+                    indices[innerAATail++] = index + 3;
+
+                    bool lower = stops.at(nextGradientStop).first > 0.5f;
+                    float dy = lower ? qMin(0.0f, height - gy - delta) : qMax(0.0f, delta - gy);
+                    smoothVertices[index++].set(rx, gy, fillColor, width - rx - delta, dy);
+                    smoothVertices[index++].set(lx, gy, fillColor, delta - lx, dy);
+                    if (penWidth) {
+                        smoothVertices[index++].set(rx, gy, borderColor, 0.49f * penWidth, (lower ? 0.49f : -0.49f) * penWidth);
+                        smoothVertices[index++].set(lx, gy, borderColor, -0.49f * penWidth, (lower ? 0.49f : -0.49f) * penWidth);
+                    } else {
+                        smoothVertices[index++].set(rx, gy, transparent, delta, lower ? delta : -delta);
+                        smoothVertices[index++].set(lx, gy, transparent, -delta, lower ? delta : -delta);
+                    }
+                } else {
+                    vertices[index++].set(rx, gy, fillColor);
+                    vertices[index++].set(lx, gy, fillColor);
+                    if (penWidth) {
+                        vertices[index++].set(rx, gy, borderColor);
+                        vertices[index++].set(lx, gy, borderColor);
+                    }
+                }
+                ++nextGradientStop;
+            }
+
+            if (!stops.isEmpty()) {
+                if (nextGradientStop == 0) {
+                    fillColor = colorToColor4ub(stops.at(0).second);
+                } else if (nextGradientStop == stops.size()) {
+                    fillColor = colorToColor4ub(stops.last().second);
+                } else {
+                    const QGradientStop &prev = stops.at(nextGradientStop - 1);
+                    const QGradientStop &next = stops.at(nextGradientStop);
+                    float t = (gradientPos - prev.first) / (next.first - prev.first);
+                    fillColor = colorToColor4ub(prev.second) * (1 - t) + colorToColor4ub(next.second) * t;
+                }
+            }
+
+            if (hasFill) {
+                indices[fillHead++] = index;
+                indices[fillHead++] = index + 1;
+            }
+
+            if (penWidth) {
+                indices[--borderHead] = index + 4;
+                indices[--borderHead] = index + 2;
+                indices[borderTail++] = index + 3;
+                indices[borderTail++] = index + 5;
+            }
+
+            if (m_antialiasing) {
+                indices[--innerAAHead] = index + 2;
+                indices[--innerAAHead] = index;
+                indices[innerAATail++] = index + 1;
+                indices[innerAATail++] = index + 3;
+
+                float dy = part == 1 ? qMin(0.0f, height - y - delta) : qMax(0.0f, delta - y);
+                smoothVertices[index++].set(rx, y, fillColor, width - rx - delta, dy);
+                smoothVertices[index++].set(lx, y, fillColor, delta - lx, dy);
+
+                if (penWidth) {
+                    smoothVertices[index++].set(rx, y, borderColor, 0.49f * penWidth, 0.49f * penWidth * part);
+                    smoothVertices[index++].set(lx, y, borderColor, -0.49f * penWidth, 0.49f * penWidth * part);
+                    smoothVertices[index++].set(rX, Y, borderColor, -0.49f * penWidth, -0.49f * penWidth * part);
+                    smoothVertices[index++].set(lX, Y, borderColor, 0.49f * penWidth, -0.49f * penWidth * part);
+                    smoothVertices[index++].set(rX, Y, transparent, delta, delta * part);
+                    smoothVertices[index++].set(lX, Y, transparent, -delta, delta * part);
+
+                    indices[--outerAAHead] = index - 2;
+                    indices[--outerAAHead] = index - 4;
+                    indices[outerAATail++] = index - 3;
+                    indices[outerAATail++] = index - 1;
+                } else {
+                    smoothVertices[index++].set(rx, y, transparent, delta, delta * part);
+                    smoothVertices[index++].set(lx, y, transparent, -delta, delta * part);
+                }
+            } else {
+                vertices[index++].set(rx, y, fillColor);
+                vertices[index++].set(lx, y, fillColor);
+                if (penWidth) {
+                    vertices[index++].set(rx, y, borderColor);
+                    vertices[index++].set(lx, y, borderColor);
+                    vertices[index++].set(rX, Y, borderColor);
+                    vertices[index++].set(lX, Y, borderColor);
+                }
+            }
+        }
+        Q_ASSERT(index == vertexCount);
+
+        // Close the triangle strips.
+        if (m_antialiasing) {
+            indices[--innerAAHead] = indices[innerAATail - 1];
+            indices[--innerAAHead] = indices[innerAATail - 2];
+            Q_ASSERT(innerAATail <= indexCount);
+        }
+        if (penWidth) {
+            indices[--borderHead] = indices[borderTail - 1];
+            indices[--borderHead] = indices[borderTail - 2];
+            Q_ASSERT(borderTail <= indexCount);
+        }
+        if (m_antialiasing && penWidth) {
+            indices[--outerAAHead] = indices[outerAATail - 1];
+            indices[--outerAAHead] = indices[outerAATail - 2];
+            Q_ASSERT(outerAATail == indexCount);
+        }
+    }
+}
+
+QT_END_NAMESPACE