1 files changed, 165 insertions, 0 deletions
diff --git a/src/plugins/platforms/wasm/qwasmbackingstore.cpp b/src/plugins/platforms/wasm/qwasmbackingstore.cpp
new file mode 100644
index 0000000000..5b40c44807
--- /dev/null
+++ b/src/plugins/platforms/wasm/qwasmbackingstore.cpp
@@ -0,0 +1,165 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) 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.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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qwasmbackingstore.h"
+#include "qwasmwindow.h"
+#include "qwasmcompositor.h"
+
+#include <QtGui/qopengltexture.h>
+#include <QtGui/qmatrix4x4.h>
+#include <QtGui/qpainter.h>
+#include <private/qguiapplication_p.h>
+#include <qpa/qplatformscreen.h>
+
+#include <QtGui/qbackingstore.h>
+
+QT_BEGIN_NAMESPACE
+
+QWasmBackingStore::QWasmBackingStore(QWasmCompositor *compositor, QWindow *window)
+    : QPlatformBackingStore(window)
+    , m_compositor(compositor)
+    , m_texture(new QOpenGLTexture(QOpenGLTexture::Target2D))
+{
+    QWasmWindow *wasmWindow = static_cast<QWasmWindow *>(window->handle());
+    if (wasmWindow)
+        wasmWindow->setBackingStore(this);
+}
+
+QWasmBackingStore::~QWasmBackingStore()
+{
+}
+
+QPaintDevice *QWasmBackingStore::paintDevice()
+{
+    return &m_image;
+}
+
+void QWasmBackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)
+{
+    Q_UNUSED(window);
+    Q_UNUSED(region);
+    Q_UNUSED(offset);
+
+    m_dirty |= region;
+    m_compositor->requestRedraw();
+}
+
+void QWasmBackingStore::updateTexture()
+{
+    if (m_dirty.isNull())
+        return;
+
+    if (!m_texture->isCreated()) {
+        m_texture->setMinificationFilter(QOpenGLTexture::Nearest);
+        m_texture->setMagnificationFilter(QOpenGLTexture::Nearest);
+        m_texture->setWrapMode(QOpenGLTexture::ClampToEdge);
+        m_texture->setData(m_image, QOpenGLTexture::DontGenerateMipMaps);
+        m_texture->create();
+    }
+    m_texture->bind();
+
+    QRegion fixed;
+    QRect imageRect = m_image.rect();
+
+    for (const QRect &rect : m_dirty) {
+
+        // Convert device-independent dirty region to device region
+        qreal dpr = m_image.devicePixelRatio();
+        QRect deviceRect = QRect(rect.topLeft() * dpr, rect.size() * dpr);
+
+        // intersect with image rect to be sure
+        QRect r = imageRect & deviceRect;
+        // if the rect is wide enough it is cheaper to just extend it instead of doing an image copy
+        if (r.width() >= imageRect.width() / 2) {
+            r.setX(0);
+            r.setWidth(imageRect.width());
+        }
+
+        fixed |= r;
+    }
+
+    for (const QRect &rect : fixed) {
+        // if the sub-rect is full-width we can pass the image data directly to
+        // OpenGL instead of copying, since there is no gap between scanlines
+        if (rect.width() == imageRect.width()) {
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, rect.y(), rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE,
+                            m_image.constScanLine(rect.y()));
+        } else {
+            glTexSubImage2D(GL_TEXTURE_2D, 0, rect.x(), rect.y(), rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE,
+                            m_image.copy(rect).constBits());
+        }
+    }
+    /* End of code taken from QEGLPlatformBackingStore */
+
+    m_dirty = QRegion();
+}
+
+void QWasmBackingStore::beginPaint(const QRegion &region)
+{
+    m_dirty |= region;
+    // Keep backing store device pixel ratio in sync with window
+    if (m_image.devicePixelRatio() != window()->devicePixelRatio())
+        resize(backingStore()->size(), backingStore()->staticContents());
+
+    QPainter painter(&m_image);
+    painter.setCompositionMode(QPainter::CompositionMode_Source);
+    const QColor blank = Qt::transparent;
+    for (const QRect &rect : region)
+        painter.fillRect(rect, blank);
+}
+
+void QWasmBackingStore::resize(const QSize &size, const QRegion &staticContents)
+{
+    Q_UNUSED(staticContents)
+
+    m_image = QImage(size * window()->devicePixelRatio(), QImage::Format_RGB32);
+    m_image.setDevicePixelRatio(window()->devicePixelRatio());
+
+    if (m_texture->isCreated())
+        m_texture->destroy();
+}
+
+QImage QWasmBackingStore::toImage() const
+{
+    // used by QPlatformBackingStore::composeAndFlush
+    return m_image;
+}
+
+const QImage &QWasmBackingStore::getImageRef() const
+{
+    return m_image;
+}
+
+const QOpenGLTexture *QWasmBackingStore::getUpdatedTexture()
+{
+    updateTexture();
+    return m_texture.data();
+}
+
+QT_END_NAMESPACE