Introduce layerering support (ShaderEffectSource) directly in Item

This is enabled by doing "Item.layer.enabled: true". The implementation
is solely based on the existing shader effect (source) and simply
swaps in a sibling next to the item when enabled.

This change also adds the QSGTextureProvider to the public API,
as it is now a natural part of the QQuickItem API since all items
can be textures.

Change-Id: I26705c11e92d5623a5121300acc123782b784077
Reviewed-by: Kim M. Kalland <kim.kalland@nokia.com>

10 files changed, 592 insertions, 0 deletions

diff --git a/tests/auto/qtquick2/qquickitemlayer/data/Effect.qml b/tests/auto/qtquick2/qquickitemlayer/data/Effect.qml
new file mode 100644
index 0000000000..630c8f90ed
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/Effect.qml
@@ -0,0 +1,34 @@
+import QtQuick 2.0
+
+Item
+{
+    width: 100
+    height: 100
+
+    Rectangle {
+        id: box
+        width: 100
+        height: 100
+
+        color: "#0000ff"
+
+        Rectangle {
+            x: 50
+            width: 50
+            height: 100
+            color: "#00ff00"
+        }
+
+        layer.enabled: true
+        layer.effect: ShaderEffect {
+            fragmentShader: "
+            uniform lowp sampler2D source;
+            uniform lowp float qt_Opacity;
+            varying highp vec2 qt_TexCoord0;
+            void main() {
+                gl_FragColor = texture2D(source, qt_TexCoord0).bgra * qt_Opacity;
+            }"
+        }
+
+    }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/Enabled.qml b/tests/auto/qtquick2/qquickitemlayer/data/Enabled.qml
new file mode 100644
index 0000000000..0e7d4f56b8
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/Enabled.qml
@@ -0,0 +1,25 @@
+import QtQuick 2.0
+
+Item
+{
+    width: 200
+    height: 200
+
+    Item {
+        width: 20
+        height: 20
+        scale: 10
+
+        layer.enabled: true
+        anchors.centerIn: parent
+
+        Rectangle {
+            width: 20
+            height: 20
+            gradient: Gradient {
+                GradientStop { position: 0; color: "white" }
+                GradientStop { position: 1; color: "black" }
+            }
+        }
+    }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/Mipmap.qml b/tests/auto/qtquick2/qquickitemlayer/data/Mipmap.qml
new file mode 100644
index 0000000000..8de41076e9
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/Mipmap.qml
@@ -0,0 +1,30 @@
+import QtQuick 2.0
+
+Item
+{
+    width: 100
+    height: 100
+
+    Rectangle {
+        id: box
+        width: 600
+        height: 600
+
+        scale: 1 / 6.
+
+        color: "black"
+
+        layer.enabled: true
+        layer.mipmap: true
+        layer.smooth: true
+
+        anchors.centerIn: parent
+
+        Rectangle {
+            x: 1
+            width: 1
+            height: parent.height
+            color: "white"
+        }
+    }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/Smooth.qml b/tests/auto/qtquick2/qquickitemlayer/data/Smooth.qml
new file mode 100644
index 0000000000..3f9575bb0b
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/Smooth.qml
@@ -0,0 +1,23 @@
+import QtQuick 2.0
+
+
+Item {
+    width: 200
+    height: 100
+
+    Row {
+        id: layerRoot
+
+        width: 20
+        height: 10
+
+        Rectangle { width: 10; height: 10; color: "red" }
+        Rectangle { width: 10; height: 10; color: "blue" }
+
+        layer.enabled: true
+        layer.smooth: true
+
+        anchors.centerIn: parent
+        scale: 10
+   }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/SourceRect.qml b/tests/auto/qtquick2/qquickitemlayer/data/SourceRect.qml
new file mode 100644
index 0000000000..7cc7e8b21e
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/SourceRect.qml
@@ -0,0 +1,33 @@
+import QtQuick 2.0
+
+Item
+{
+    width: 100
+    height: 100
+
+    Rectangle {
+        id: box
+        width: 100
+        height: 100
+
+        color: "#ff0000"
+
+        layer.enabled: true
+        layer.sourceRect: Qt.rect(-10, -10, box.width + 20, box.height + 20);
+
+        // A shader that pads the transparent pixels with blue.
+        layer.effect: ShaderEffect {
+            fragmentShader: "
+            uniform lowp sampler2D source;
+            uniform lowp float qt_Opacity;
+            varying highp vec2 qt_TexCoord0;
+            void main() {
+                vec4 c = texture2D(source, qt_TexCoord0);
+                if (c.a == 0.)
+                    c = vec4(0, 0, 1, 1);
+                gl_FragColor = c * qt_Opacity;
+            }
+            "
+        }
+    }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/TextureProvider.qml b/tests/auto/qtquick2/qquickitemlayer/data/TextureProvider.qml
new file mode 100644
index 0000000000..ccd515652a
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/TextureProvider.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item
+{
+    width: 100
+    height: 100
+
+    Rectangle {
+        id: box
+        width: 100
+        height: 100
+
+        color: "#0000ff"
+
+        Rectangle {
+            x: 50
+            width: 50
+            height: 100
+            color: "#00ff00"
+        }
+
+        visible: false
+
+        layer.enabled: true
+    }
+
+    ShaderEffect {
+        anchors.fill: parent
+        property variant source: box
+
+        fragmentShader: "
+        uniform lowp sampler2D source;
+        uniform lowp float qt_Opacity;
+        varying highp vec2 qt_TexCoord0;
+        void main() {
+            gl_FragColor = texture2D(source, qt_TexCoord0).bgra * qt_Opacity;
+        }"
+    }
+
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/Visible.qml b/tests/auto/qtquick2/qquickitemlayer/data/Visible.qml
new file mode 100644
index 0000000000..8267f18250
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/Visible.qml
@@ -0,0 +1,56 @@
+import QtQuick 2.0
+
+Item
+{
+    id: root
+
+    width: 100
+    height: 100
+
+    property bool layerEffect: false;
+    onLayerEffectChanged: root.maybeUse();
+    Component.onCompleted: root.maybeUse();
+
+    property real layerOpacity: 1;
+    property bool layerVisible: true;
+
+    function maybeUse() {
+        if (root.layerEffect)
+            box.layer.effect = shaderEffect
+    }
+
+    Component {
+        id: shaderEffect
+        ShaderEffect {
+            fragmentShader: "
+                uniform lowp sampler2D source;
+                uniform lowp float qt_Opacity;
+                varying highp vec2 qt_TexCoord0;
+                void main() {
+                    gl_FragColor = texture2D(source, qt_TexCoord0).bgra * qt_Opacity;
+                }
+            "
+        }
+
+    }
+
+    Rectangle {
+        id: box
+        width: 100
+        height: 100
+
+        color: "#0000ff"
+        visible: parent.layerVisible;
+        opacity: parent.layerOpacity;
+
+        Rectangle {
+            x: 50
+            width: 50
+            height: 100
+            color: "#00ff00"
+        }
+
+        layer.enabled: true
+
+    }
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/data/ZOrder.qml b/tests/auto/qtquick2/qquickitemlayer/data/ZOrder.qml
new file mode 100644
index 0000000000..59ccb32224
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/data/ZOrder.qml
@@ -0,0 +1,52 @@
+import QtQuick 2.0
+
+Item
+{
+    id: root
+
+    width: 200
+    height: 200
+
+    Component {
+        id: shaderEffect
+        ShaderEffect { }
+    }
+
+    property bool layerEffect: false;
+    onLayerEffectChanged: root.maybeUse();
+    Component.onCompleted: root.maybeUse();
+
+    function maybeUse() {
+        if (root.layerEffect)
+            box.layer.effect = shaderEffect
+    }
+
+
+    Rectangle {
+        color: "red"
+        anchors.left: parent.left
+        anchors.top: parent.top
+        width: 100
+        height: 100
+        z: 1
+    }
+
+    Rectangle {
+        color: "#00ff00"
+        anchors.bottom: parent.bottom
+        anchors.right: parent.right
+        width: 100
+        height: 100
+        z: 3
+    }
+
+    Rectangle {
+        id: box
+        color: "blue"
+        anchors.fill: parent
+        anchors.margins: 10
+        layer.enabled: true
+        z: 2
+    }
+
+}
diff --git a/tests/auto/qtquick2/qquickitemlayer/qquickitemlayer.pro b/tests/auto/qtquick2/qquickitemlayer/qquickitemlayer.pro
new file mode 100644
index 0000000000..bf22d04f23
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/qquickitemlayer.pro
@@ -0,0 +1,32 @@
+CONFIG += testcase
+TARGET = tst_qquickitemlayer
+SOURCES += tst_qquickitemlayer.cpp
+
+macx:CONFIG -= app_bundle
+
+testDataFiles.files = data
+testDataFiles.path = .
+DEPLOYMENT += testDataFiles
+
+include(../../shared/util.pri)
+
+CONFIG += parallel_test
+QT += core-private gui-private v8-private declarative-private quick-private testlib
+
+OTHER_FILES += \
+    data/Smooth.qml \
+    data/Enabled.qml \
+    data/Mipmap.qml \
+    data/Effect.qml \
+    data/SourceRect.qml \
+    data/TextureProvider.qml \
+    data/Visible.qml \
+    data/ZOrder.qml
+
+
+
+
+
+
+
+
diff --git a/tests/auto/qtquick2/qquickitemlayer/tst_qquickitemlayer.cpp b/tests/auto/qtquick2/qquickitemlayer/tst_qquickitemlayer.cpp
new file mode 100644
index 0000000000..2b7a16997c
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitemlayer/tst_qquickitemlayer.cpp
@@ -0,0 +1,267 @@
+/****************************************************************************
+**
+** 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 test suite 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 <qtest.h>
+
+#include <QtQuick/qquickitem.h>
+#include <QtQuick/qquickview.h>
+
+#include "../../shared/util.h"
+
+class tst_QQuickItemLayer: public QDeclarativeDataTest
+{
+    Q_OBJECT
+public:
+    tst_QQuickItemLayer();
+
+    QImage runTest(const QString &url)
+    {
+        QQuickView view;
+        view.setSource(QUrl(url));
+
+        view.show();
+        QTest::qWaitForWindowShown(&view);
+
+        return view.grabFrameBuffer();
+    }
+
+private slots:
+    void layerEnabled();
+    void layerSmooth();
+    void layerMipmap();
+    void layerEffect();
+
+    void layerVisibility_data();
+    void layerVisibility();
+
+    void layerSourceRect();
+
+
+    void layerZOrder_data();
+    void layerZOrder();
+
+    void layerIsTextureProvider();
+};
+
+tst_QQuickItemLayer::tst_QQuickItemLayer()
+{
+}
+
+
+
+// The test draws a red and a blue box next to each other and tests that the
+// output is still red and blue on the left and right and a combination of
+// the two in the middle.
+
+void tst_QQuickItemLayer::layerSmooth()
+{
+    QImage fb = runTest(testFile("Smooth.qml"));
+    QCOMPARE(fb.pixel(0, 0), qRgb(0xff, 0, 0));
+    QCOMPARE(fb.pixel(fb.width() - 1, 0), qRgb(0, 0, 0xff));
+
+    uint pixel = fb.pixel(fb.width() / 2, 0);
+    QVERIFY(qRed(pixel) > 0);
+    QVERIFY(qBlue(pixel) > 0);
+}
+
+
+
+// The test draws a gradient at a small size into a layer and scales the
+// layer. If the layer is enabled there should be very visible bands in
+// the gradient.
+
+void tst_QQuickItemLayer::layerEnabled()
+{
+    QImage fb = runTest(testFile("Enabled.qml"));
+    // Verify the banding
+    QCOMPARE(fb.pixel(0, 0), fb.pixel(0, 1));
+    // Verify the gradient
+    QVERIFY(fb.pixel(0, 0) != fb.pixel(0, fb.height() - 1));
+}
+
+
+
+// The test draws a one pixel wide line and scales it down by more than a a factor 2
+// If mipmpping works, the pixels should be gray, not white or black
+
+void tst_QQuickItemLayer::layerMipmap()
+{
+    QImage fb = runTest(testFile("Mipmap.qml"));
+    QVERIFY(fb.pixel(0, 0) != 0xff000000);
+    QVERIFY(fb.pixel(0, 0) != 0xffffffff);
+}
+
+
+
+// The test implements an rgb swapping effect sourced from a blue rectangle. The
+// resulting pixel should be red
+
+void tst_QQuickItemLayer::layerEffect()
+{
+    QImage fb = runTest(testFile("Effect.qml"));
+    QCOMPARE(fb.pixel(0, 0), qRgb(0xff, 0, 0));
+    QCOMPARE(fb.pixel(fb.width() - 1, 0), qRgb(0, 0xff, 0));
+}
+
+
+
+// The test draws a rectangle and verifies that there is padding on each side
+// as the source rect spans outside the item. The padding is verified using
+// a shader that pads transparent to blue. Everything else is red.
+void tst_QQuickItemLayer::layerSourceRect()
+{
+    QImage fb = runTest(testFile("SourceRect.qml"));
+
+    // Check that the edges are converted to blue
+    QCOMPARE(fb.pixel(0, 0), qRgb(0, 0, 0xff));
+    QCOMPARE(fb.pixel(fb.width() - 1, 0), qRgb(0, 0, 0xff));
+    QCOMPARE(fb.pixel(0, fb.height() - 1), qRgb(0, 0, 0xff));
+    QCOMPARE(fb.pixel(fb.width() - 1, fb.height() - 1), qRgb(0, 0, 0xff));
+
+    // The center pixel should be red
+    QCOMPARE(fb.pixel(fb.width() / 2, fb.height() / 2), qRgb(0xff, 0, 0));
+}
+
+
+
+// Same as the effect test up above, but this time use the item
+// directly in a stand alone ShaderEffect
+void tst_QQuickItemLayer::layerIsTextureProvider()
+{
+    QImage fb = runTest(testFile("TextureProvider.qml"));
+    QCOMPARE(fb.pixel(0, 0), qRgb(0xff, 0, 0));
+    QCOMPARE(fb.pixel(fb.width() - 1, 0), qRgb(0, 0xff, 0));
+}
+
+
+void tst_QQuickItemLayer::layerVisibility_data()
+{
+    QTest::addColumn<bool>("visible");
+    QTest::addColumn<bool>("effect");
+    QTest::addColumn<qreal>("opacity");
+
+    QTest::newRow("!effect, !visible, a=1") << false << false << 1.;
+    QTest::newRow("!effect, visible, a=1") << false << true << 1.;
+    QTest::newRow("effect, !visible, a=1") << true << false << 1.;
+    QTest::newRow("effect, visible, a=1") << true << true << 1.;
+
+    QTest::newRow("!effect, !visible, a=.5") << false << false << .5;
+    QTest::newRow("!effect, visible, a=.5") << false << true << .5;
+    QTest::newRow("effect, !visible, a=.5") << true << false << .5;
+    QTest::newRow("effect, visible, a=.5") << true << true << .5;
+
+    QTest::newRow("!effect, !visible, a=0") << false << false << 0.;
+    QTest::newRow("!effect, visible, a=0") << false << true << 0.;
+    QTest::newRow("effect, !visible, a=0") << true << false << 0.;
+    QTest::newRow("effect, visible, a=0") << true << true << 0.;
+}
+
+void tst_QQuickItemLayer::layerVisibility()
+{
+    QFETCH(bool, visible);
+    QFETCH(bool, effect);
+    QFETCH(qreal, opacity);
+
+    QQuickView view;
+    view.setSource(testFile("Visible.qml"));
+
+    QQuickItem *child = view.rootItem()->childItems().at(0);
+    child->setProperty("layerVisible", visible);
+    child->setProperty("layerEffect", effect);
+    child->setProperty("layerOpacity", opacity);
+
+    view.show();
+
+    QTest::qWaitForWindowShown(&view);
+
+    QImage fb = view.grabFrameBuffer();
+    uint pixel = fb.pixel(0, 0);
+
+    if (!visible || opacity == 0) {
+        QCOMPARE(pixel, qRgb(0xff, 0xff, 0xff));
+    } else if (effect) {
+        QCOMPARE(qRed(pixel), 0xff);
+        QVERIFY(qGreen(pixel) < 0xff);
+        QVERIFY(qBlue(pixel) < 0xff);
+    } else { // no effect
+        QCOMPARE(qBlue(pixel), 0xff);
+        QVERIFY(qGreen(pixel) < 0xff);
+        QVERIFY(qRed(pixel) < 0xff);
+    }
+}
+
+
+
+
+void tst_QQuickItemLayer::layerZOrder_data()
+{
+    QTest::addColumn<bool>("effect");
+
+    QTest::newRow("!effect") << false;
+    QTest::newRow("effect") << true;
+}
+
+void tst_QQuickItemLayer::layerZOrder()
+{
+    QFETCH(bool, effect);
+
+    QQuickView view;
+    view.setSource(testFile("ZOrder.qml"));
+
+    QQuickItem *child = view.rootItem()->childItems().at(0);
+    child->setProperty("layerEffect", effect);
+
+    view.show();
+
+    QTest::qWaitForWindowShown(&view);
+
+    QImage fb = view.grabFrameBuffer();
+
+    QCOMPARE(fb.pixel(50, 50), qRgb(0, 0, 0xff));
+    QCOMPARE(fb.pixel(150, 150), qRgb(0, 0xff, 00));
+
+}
+
+
+
+QTEST_MAIN(tst_QQuickItemLayer)
+
+#include "tst_qquickitemlayer.moc"