eglfs: Move reusable functionality to eglconvenience

The cursor implementation is generic GL(ES) code that should be shared
by all the present and future egl-based embedded platform
plugins. Follow the pattern of QEGLPlatformContext and move this class
into eglconvenience as QEGLPlatformCursor.

Similarly, the common bits from the context implementation context are
moved back to EGLPlatformContext.

eglconvenience has now base classes for integration, screen, window,
etc. too. By using these, eglfs becomes much smaller and cleaner. This
also paves the way for creating new, separate EGL-based platform
plugins for Android, embedded Linux, etc.

Also added some documentation to each of the base classes.

devicediscovery is now fixed to be usable on any platform. The
implementation in this case is naturally a dummy one. This finally
allows using it from anywhere without myriads of ugly ifdefs.

Change-Id: I02946e360c04e02de7fe234a23a08320eff4ccf5
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>

1 files changed, 353 insertions, 0 deletions

diff --git a/src/platformsupport/eglconvenience/qeglplatformcursor.cpp b/src/platformsupport/eglconvenience/qeglplatformcursor.cpp
new file mode 100644
index 0000000000..55590dbc9e
--- /dev/null
+++ b/src/platformsupport/eglconvenience/qeglplatformcursor.cpp
@@ -0,0 +1,353 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qeglplatformcursor_p.h"
+#include <qpa/qwindowsysteminterface.h>
+#include <QtGui/QOpenGLContext>
+#include <QtGui/QOpenGLShaderProgram>
+#include <QtCore/QJsonDocument>
+#include <QtCore/QJsonArray>
+#include <QtCore/QJsonObject>
+#include <QtDebug>
+
+#include <QtPlatformSupport/private/qdevicediscovery_p.h>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QEGLPlatformCursor
+    \brief Mouse cursor implementation using OpenGL.
+    \since 5.2
+    \internal
+    \ingroup qpa
+ */
+
+QEGLPlatformCursor::QEGLPlatformCursor(QPlatformScreen *screen)
+    : m_visible(true),
+      m_screen(screen),
+      m_program(0),
+      m_vertexCoordEntry(0),
+      m_textureCoordEntry(0),
+      m_textureEntry(0)
+{
+    QByteArray hideCursorVal = qgetenv("QT_QPA_EGLFS_HIDECURSOR");
+    if (hideCursorVal.isEmpty()) {
+        QScopedPointer<QDeviceDiscovery> dis(QDeviceDiscovery::create(QDeviceDiscovery::Device_Mouse));
+        m_visible = !dis->scanConnectedDevices().isEmpty();
+    } else {
+        m_visible = hideCursorVal.toInt() == 0;
+    }
+    if (!m_visible)
+        return;
+
+    // Try to load the cursor atlas. If this fails, m_visible is set to false and
+    // paintOnScreen() and setCurrentCursor() become no-ops.
+    initCursorAtlas();
+
+    // initialize the cursor
+#ifndef QT_NO_CURSOR
+    QCursor cursor(Qt::ArrowCursor);
+    setCurrentCursor(&cursor);
+#endif
+}
+
+QEGLPlatformCursor::~QEGLPlatformCursor()
+{
+    resetResources();
+}
+
+void QEGLPlatformCursor::resetResources()
+{
+    if (QOpenGLContext::currentContext()) {
+        delete m_program;
+        glDeleteTextures(1, &m_cursor.customCursorTexture);
+        glDeleteTextures(1, &m_cursorAtlas.texture);
+    }
+    m_program = 0;
+    m_cursor.customCursorTexture = 0;
+    m_cursor.customCursorPending = !m_cursor.customCursorImage.isNull();
+    m_cursorAtlas.texture = 0;
+}
+
+void QEGLPlatformCursor::createShaderPrograms()
+{
+    static const char *textureVertexProgram =
+        "attribute highp vec2 vertexCoordEntry;\n"
+        "attribute highp vec2 textureCoordEntry;\n"
+        "varying highp vec2 textureCoord;\n"
+        "void main() {\n"
+        "   textureCoord = textureCoordEntry;\n"
+        "   gl_Position = vec4(vertexCoordEntry, 1.0, 1.0);\n"
+        "}\n";
+
+    static const char *textureFragmentProgram =
+        "uniform sampler2D texture;\n"
+        "varying highp vec2 textureCoord;\n"
+        "void main() {\n"
+        "   gl_FragColor = texture2D(texture, textureCoord).bgra;\n"
+        "}\n";
+
+    m_program = new QOpenGLShaderProgram;
+    m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, textureVertexProgram);
+    m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, textureFragmentProgram);
+    m_program->link();
+
+    m_vertexCoordEntry = m_program->attributeLocation("vertexCoordEntry");
+    m_textureCoordEntry = m_program->attributeLocation("textureCoordEntry");
+    m_textureEntry = m_program->attributeLocation("texture");
+}
+
+void QEGLPlatformCursor::createCursorTexture(uint *texture, const QImage &image)
+{
+    if (!*texture)
+        glGenTextures(1, texture);
+    glBindTexture(GL_TEXTURE_2D, *texture);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+    glTexImage2D(GL_TEXTURE_2D, 0 /* level */, GL_RGBA, image.width(), image.height(), 0 /* border */,
+                 GL_RGBA, GL_UNSIGNED_BYTE, image.constBits());
+}
+
+void QEGLPlatformCursor::initCursorAtlas()
+{
+    static QByteArray json = qgetenv("QT_QPA_EGLFS_CURSOR");
+    if (json.isEmpty())
+        json = ":/cursor.json";
+
+    QFile file(QString::fromUtf8(json));
+    if (!file.open(QFile::ReadOnly)) {
+        m_visible = false;
+        return;
+    }
+
+    QJsonDocument doc = QJsonDocument::fromJson(file.readAll());
+    QJsonObject object = doc.object();
+
+    QString atlas = object.value(QLatin1String("image")).toString();
+    Q_ASSERT(!atlas.isEmpty());
+
+    const int cursorsPerRow = object.value(QLatin1String("cursorsPerRow")).toDouble();
+    Q_ASSERT(cursorsPerRow);
+    m_cursorAtlas.cursorsPerRow = cursorsPerRow;
+
+    const QJsonArray hotSpots = object.value(QLatin1String("hotSpots")).toArray();
+    Q_ASSERT(hotSpots.count() == Qt::LastCursor);
+    for (int i = 0; i < hotSpots.count(); i++) {
+        QPoint hotSpot(hotSpots[i].toArray()[0].toDouble(), hotSpots[i].toArray()[1].toDouble());
+        m_cursorAtlas.hotSpots << hotSpot;
+    }
+
+    QImage image = QImage(atlas).convertToFormat(QImage::Format_ARGB32_Premultiplied);
+    m_cursorAtlas.cursorWidth = image.width() / m_cursorAtlas.cursorsPerRow;
+    m_cursorAtlas.cursorHeight = image.height() / ((Qt::LastCursor + cursorsPerRow - 1) / cursorsPerRow);
+    m_cursorAtlas.width = image.width();
+    m_cursorAtlas.height = image.height();
+    m_cursorAtlas.image = image;
+}
+
+#ifndef QT_NO_CURSOR
+void QEGLPlatformCursor::changeCursor(QCursor *cursor, QWindow *window)
+{
+    Q_UNUSED(window);
+    const QRect oldCursorRect = cursorRect();
+    if (setCurrentCursor(cursor))
+        update(oldCursorRect | cursorRect());
+}
+
+bool QEGLPlatformCursor::setCurrentCursor(QCursor *cursor)
+{
+    if (!m_visible)
+        return false;
+
+    const Qt::CursorShape newShape = cursor ? cursor->shape() : Qt::ArrowCursor;
+    if (m_cursor.shape == newShape && newShape != Qt::BitmapCursor)
+        return false;
+
+    if (m_cursor.shape == Qt::BitmapCursor) {
+        m_cursor.customCursorImage = QImage();
+        m_cursor.customCursorPending = false;
+    }
+    m_cursor.shape = newShape;
+    if (newShape != Qt::BitmapCursor) { // standard cursor
+        const float ws = (float)m_cursorAtlas.cursorWidth / m_cursorAtlas.width,
+                    hs = (float)m_cursorAtlas.cursorHeight / m_cursorAtlas.height;
+        m_cursor.textureRect = QRectF(ws * (m_cursor.shape % m_cursorAtlas.cursorsPerRow),
+                                      hs * (m_cursor.shape / m_cursorAtlas.cursorsPerRow),
+                                      ws, hs);
+        m_cursor.hotSpot = m_cursorAtlas.hotSpots[m_cursor.shape];
+        m_cursor.texture = m_cursorAtlas.texture;
+        m_cursor.size = QSize(m_cursorAtlas.cursorWidth, m_cursorAtlas.cursorHeight);
+    } else {
+        QImage image = cursor->pixmap().toImage();
+        m_cursor.textureRect = QRectF(0, 0, 1, 1);
+        m_cursor.hotSpot = cursor->hotSpot();
+        m_cursor.texture = 0; // will get updated in the next render()
+        m_cursor.size = image.size();
+        m_cursor.customCursorImage = image;
+        m_cursor.customCursorPending = true;
+    }
+
+    return true;
+}
+#endif
+
+void QEGLPlatformCursor::update(const QRegion &rgn)
+{
+    QWindowSystemInterface::handleExposeEvent(m_screen->topLevelAt(m_cursor.pos), rgn);
+    QWindowSystemInterface::flushWindowSystemEvents();
+}
+
+QRect QEGLPlatformCursor::cursorRect() const
+{
+    return QRect(m_cursor.pos - m_cursor.hotSpot, m_cursor.size);
+}
+
+QPoint QEGLPlatformCursor::pos() const
+{
+    return m_cursor.pos;
+}
+
+void QEGLPlatformCursor::setPos(const QPoint &pos)
+{
+    const QRect oldCursorRect = cursorRect();
+    m_cursor.pos = pos;
+    update(oldCursorRect | cursorRect());
+}
+
+void QEGLPlatformCursor::pointerEvent(const QMouseEvent &event)
+{
+    if (event.type() != QEvent::MouseMove)
+        return;
+    const QRect oldCursorRect = cursorRect();
+    m_cursor.pos = event.screenPos().toPoint();
+    update(oldCursorRect | cursorRect());
+}
+
+void QEGLPlatformCursor::paintOnScreen()
+{
+    if (!m_visible)
+        return;
+
+    const QRectF cr = cursorRect();
+    const QRect screenRect(m_screen->geometry());
+    const GLfloat x1 = 2 * (cr.left() / screenRect.width()) - 1;
+    const GLfloat x2 = 2 * (cr.right() / screenRect.width()) - 1;
+    const GLfloat y1 = 1 - (cr.top() / screenRect.height()) * 2;
+    const GLfloat y2 = 1 - (cr.bottom() / screenRect.height()) * 2;
+    QRectF r(QPointF(x1, y1), QPointF(x2, y2));
+
+    draw(r);
+}
+
+void QEGLPlatformCursor::draw(const QRectF &r)
+{
+    if (!m_program) {
+        // one time initialization
+        createShaderPrograms();
+
+        if (!m_cursorAtlas.texture) {
+            createCursorTexture(&m_cursorAtlas.texture, m_cursorAtlas.image);
+
+            if (m_cursor.shape != Qt::BitmapCursor)
+                m_cursor.texture = m_cursorAtlas.texture;
+        }
+    }
+
+    if (m_cursor.shape == Qt::BitmapCursor && m_cursor.customCursorPending) {
+        // upload the custom cursor
+        createCursorTexture(&m_cursor.customCursorTexture, m_cursor.customCursorImage);
+        m_cursor.texture = m_cursor.customCursorTexture;
+        m_cursor.customCursorPending = false;
+    }
+
+    Q_ASSERT(m_cursor.texture);
+
+    m_program->bind();
+
+    const GLfloat x1 = r.left();
+    const GLfloat x2 = r.right();
+    const GLfloat y1 = r.top();
+    const GLfloat y2 = r.bottom();
+    const GLfloat cursorCoordinates[] = {
+        x1, y2,
+        x2, y2,
+        x1, y1,
+        x2, y1
+    };
+
+    const GLfloat s1 = m_cursor.textureRect.left();
+    const GLfloat s2 = m_cursor.textureRect.right();
+    const GLfloat t1 = m_cursor.textureRect.top();
+    const GLfloat t2 = m_cursor.textureRect.bottom();
+    const GLfloat textureCoordinates[] = {
+        s1, t2,
+        s2, t2,
+        s1, t1,
+        s2, t1
+    };
+
+    glBindTexture(GL_TEXTURE_2D, m_cursor.texture);
+
+    m_program->enableAttributeArray(m_vertexCoordEntry);
+    m_program->enableAttributeArray(m_textureCoordEntry);
+
+    m_program->setAttributeArray(m_vertexCoordEntry, cursorCoordinates, 2);
+    m_program->setAttributeArray(m_textureCoordEntry, textureCoordinates, 2);
+
+    m_program->setUniformValue(m_textureEntry, 0);
+
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+    glDisable(GL_DEPTH_TEST); // disable depth testing to make sure cursor is always on top
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    glDisable(GL_BLEND);
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+    m_program->disableAttributeArray(m_textureCoordEntry);
+    m_program->disableAttributeArray(m_vertexCoordEntry);
+
+    m_program->release();
+}
+
+QT_END_NAMESPACE