Fix: Do not enforce TextureImage to be parented only by Texture

This behavior prevented using TextureImage not directly parented by the
Texture that uses them (assert would be triggered). In turn, this also
prevents sharing a TextureImage among several Texture instances which is
counter productive since this is where the data is actually stored.

This patch fixes this issue. It removes all direct coupling between Texture
and TextureImages. Now Texture only contains the list of TextureImage ids it
references. This allows to not make look-ups into the TextureImageManager to
retrieve handles, which could be an issue if TextureImages have not yet had
their backend created. TextureImage doesn't keep track of the referencing texture
that uses it anymore. Instead, we let the renderer do the job of checking if any of
the TextureImage referenced by a Texture has changed to trigger actual Texture
update.

Change-Id: I3c63379d0f4b314e9b53f225870eeaded0bb4aec
Task-number: QTBUG-69407
Reviewed-by: Mike Krus <mike.krus@kdab.com>

6 files changed, 224 insertions, 1 deletions

diff --git a/tests/manual/manual.pro b/tests/manual/manual.pro
index b1e16fc0b..3dcdae8a0 100644
--- a/tests/manual/manual.pro
+++ b/tests/manual/manual.pro
@@ -56,7 +56,8 @@ SUBDIRS += \
     proximityfilter \
     rendercapture-qml-fbo \
     blitframebuffer-qml \
-    raycasting-qml
+    raycasting-qml \
+    shared_texture_image
 
 qtHaveModule(widgets): {
     SUBDIRS += \
diff --git a/tests/manual/shared_texture_image/image.png b/tests/manual/shared_texture_image/image.png
new file mode 100644
index 000000000..6ab28d44a
--- /dev/null
+++ b/tests/manual/shared_texture_image/image.png
diff --git a/tests/manual/shared_texture_image/main.cpp b/tests/manual/shared_texture_image/main.cpp
new file mode 100644
index 000000000..01e3080d2
--- /dev/null
+++ b/tests/manual/shared_texture_image/main.cpp
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <Qt3DQuickExtras/qt3dquickwindow.h>
+#include <QGuiApplication>
+
+int main(int argc, char* argv[])
+{
+    QGuiApplication app(argc, argv);
+    Qt3DExtras::Quick::Qt3DQuickWindow view;
+    view.setSource(QUrl("qrc:/main.qml"));
+    view.show();
+
+    return app.exec();
+}
diff --git a/tests/manual/shared_texture_image/main.qml b/tests/manual/shared_texture_image/main.qml
new file mode 100644
index 000000000..577649f63
--- /dev/null
+++ b/tests/manual/shared_texture_image/main.qml
@@ -0,0 +1,144 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.2 as QQ2
+import Qt3D.Core 2.0
+import Qt3D.Render 2.0
+import Qt3D.Input 2.0
+import Qt3D.Extras 2.0
+
+Entity {
+    id: sceneRoot
+
+    Camera {
+        id: camera
+        projectionType: CameraLens.PerspectiveProjection
+        fieldOfView: 45
+        aspectRatio: 16/9
+        nearPlane : 0.1
+        farPlane : 1000.0
+        position: Qt.vector3d( 0.0, 0.0, -40.0 )
+        upVector: Qt.vector3d( 0.0, 1.0, 0.0 )
+        viewCenter: Qt.vector3d( 0.0, 0.0, 0.0 )
+    }
+
+    OrbitCameraController {
+        camera: camera
+    }
+
+    components: [
+        RenderSettings {
+            activeFrameGraph: ForwardRenderer {
+                clearColor: Qt.rgba(0, 0.5, 1, 1)
+                camera: camera
+            }
+        },
+        // Event Source will be set by the Qt3DQuickWindow
+        InputSettings { }
+    ]
+
+    // 2 Textures can reference the same texture image
+    // (Though it's up to the user to make sure that the images are compatible with the textures)
+    // If the 2 Textures contain the exact same number of images and filtering options
+    // Qt3D will only generate 1 actual GL texture, if they differ, 2 will be generated
+    TextureImage {
+        id: mainImage
+        source: "qrc:/image.png"
+    }
+
+    readonly property GeometryRenderer mesh: CuboidMesh {}
+
+    Entity {
+        id: leftCube
+
+        readonly property Transform transform: Transform {
+            translation: Qt.vector3d(-10, 0, 0)
+            scale: 10
+        }
+
+        readonly property DiffuseMapMaterial material: DiffuseMapMaterial {
+            diffuse: Texture2D {
+                generateMipMaps: false
+                minificationFilter: Texture.Nearest
+                magnificationFilter: Texture.Nearest
+                wrapMode {
+                    x: WrapMode.ClampToEdge
+                    y: WrapMode.ClampToEdge
+                }
+                textureImages: [mainImage]
+            }
+        }
+        components: [ mesh, material, transform ]
+    }
+
+    Entity {
+        id: rightCube
+
+        readonly property Transform transform: Transform {
+            translation: Qt.vector3d(10, 0, 0)
+            scale: 10
+        }
+
+        readonly property DiffuseMapMaterial material: DiffuseMapMaterial {
+            diffuse: Texture2D {
+                generateMipMaps: true
+                minificationFilter: Texture.LinearMipMapLinear
+                magnificationFilter: Texture.Linear
+                maximumAnisotropy: 16.0
+                wrapMode {
+                    x: WrapMode.ClampToEdge
+                    y: WrapMode.ClampToEdge
+                }
+                textureImages: [mainImage]
+            }
+        }
+        components: [ mesh, material, transform ]
+    }
+}
diff --git a/tests/manual/shared_texture_image/shared_texture_image.pro b/tests/manual/shared_texture_image/shared_texture_image.pro
new file mode 100644
index 000000000..833935698
--- /dev/null
+++ b/tests/manual/shared_texture_image/shared_texture_image.pro
@@ -0,0 +1,10 @@
+QT += 3dcore 3drender 3dinput 3dquick 3dlogic qml quick 3dquickextras
+
+SOURCES += \
+    main.cpp
+
+OTHER_FILES += \
+    main.qml
+
+RESOURCES += \
+    shared_texture_image.qrc
diff --git a/tests/manual/shared_texture_image/shared_texture_image.qrc b/tests/manual/shared_texture_image/shared_texture_image.qrc
new file mode 100644
index 000000000..879435bec
--- /dev/null
+++ b/tests/manual/shared_texture_image/shared_texture_image.qrc
@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/">
+        <file>main.qml</file>
+        <file>image.png</file>
+    </qresource>
+</RCC>