QOpenGLTextureBlitter

private api, but useful for 2d gui code that suddenly finds itself
needing to get a set of textures onto some fbo

I didn't want to include ARB_copy_image since it looks like its from
texture/renderbuffer -> texture/renderbuffer while this class implies
texture -> write fbo. We could wrap ARB_copy_image in QOpenGLTexture or
some other class or we can add it later.

I have not added any QOpenGLTexture functions since this class opperates
on the GLuint identifier. We can add overloads later.

Change-Id: I3e565b33466c1c183a249a33c3e82c6786debd55
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>

1 files changed, 167 insertions, 0 deletions

diff --git a/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp b/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp
new file mode 100644
index 0000000000..0dac669887
--- /dev/null
+++ b/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp
@@ -0,0 +1,167 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite 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 "qopengltextureblitwindow.h"
+
+#include <QtGui/QPainter>
+#include <QtGui/QOpenGLTexture>
+#include <QtGui/QMatrix4x4>
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QDebug>
+
+QOpenGLTextureBlitWindow::QOpenGLTextureBlitWindow()
+    : QWindow()
+    , m_context(new QOpenGLContext(this))
+{
+    resize(500,500);
+    setSurfaceType(OpenGLSurface);
+    QSurfaceFormat surfaceFormat = format();
+    if (QCoreApplication::arguments().contains(QStringLiteral("-coreprofile"))) {
+        surfaceFormat.setVersion(3,2);
+        surfaceFormat.setProfile(QSurfaceFormat::CoreProfile);
+    }
+
+    setFormat(surfaceFormat);
+    create();
+    m_context->setFormat(surfaceFormat);
+    m_context->create();
+
+    m_context->makeCurrent(this);
+
+    m_blitter.create();
+}
+
+void QOpenGLTextureBlitWindow::render()
+{
+    m_context->makeCurrent(this);
+
+    QRect viewport(0,0,dWidth(),dHeight());
+    glViewport(0,0,dWidth(), dHeight());
+
+    glClearColor(0.f, .6f, .0f, 0.f);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    QOpenGLTexture texture(m_image);
+    texture.create();
+
+    QRectF topLeft(QPointF(0,0), QPointF(dWidth()/2.0, dHeight()/2.0));
+    QRectF topRight(QPointF(dWidth()/2.0,0), QPointF(dWidth(), dHeight()/2.0));
+    QRectF bottomLeft(QPointF(0, dHeight()/2.0), QPointF(dWidth() /2.0, dHeight()));
+    QRectF bottomRight(QPoint(dWidth()/2.0, dHeight()/2.0), QPointF(dWidth(), dHeight()));
+
+    QOpenGLTextureBlitter::Origin topLeftOrigin = QOpenGLTextureBlitter::OriginTopLeft;
+    QOpenGLTextureBlitter::Origin bottomLeftOrigin = QOpenGLTextureBlitter::OriginBottomLeft;
+    QMatrix4x4 topRightVertexFlipped = QOpenGLTextureBlitter::targetTransform(topRight, viewport, topLeftOrigin);
+    QMatrix4x4 bottomLeftVertex = QOpenGLTextureBlitter::targetTransform(bottomLeft, viewport, topLeftOrigin);
+    QMatrix4x4 bottomRightVertexFlipped = QOpenGLTextureBlitter::targetTransform(bottomRight, viewport, topLeftOrigin);
+
+    QMatrix3x3 texTopLeft = QOpenGLTextureBlitter::sourceTransform(topLeft, m_image.size(), topLeftOrigin);
+    QMatrix3x3 texTopRight = QOpenGLTextureBlitter::sourceTransform(topRight, m_image.size(), topLeftOrigin);
+    QMatrix3x3 texBottomLeft = QOpenGLTextureBlitter::sourceTransform(bottomLeft, m_image.size(), topLeftOrigin);
+    QMatrix3x3 texBottomRight = QOpenGLTextureBlitter::sourceTransform(bottomRight, m_image.size(), bottomLeftOrigin);
+
+    QSizeF subSize(topLeft.width()/2, topLeft.height()/2);
+    QRectF subTopLeft(topLeft.topLeft(), subSize);
+    QRectF subTopRight(QPointF(topLeft.topLeft().x() + topLeft.width() / 2, topLeft.topLeft().y()),subSize);
+    QRectF subBottomLeft(QPointF(topLeft.topLeft().x(), topLeft.topLeft().y() + topLeft.height() / 2), subSize);
+    QRectF subBottomRight(QPointF(topLeft.topLeft().x() + topLeft.width() / 2, topLeft.topLeft().y() + topLeft.height() / 2), subSize);
+
+    QMatrix4x4 subTopLeftVertex = QOpenGLTextureBlitter::targetTransform(subTopLeft, viewport, topLeftOrigin);
+    QMatrix4x4 subTopRightVertex = QOpenGLTextureBlitter::targetTransform(subTopRight, viewport, topLeftOrigin);
+    QMatrix4x4 subBottomLeftVertex = QOpenGLTextureBlitter::targetTransform(subBottomLeft, viewport, topLeftOrigin);
+    QMatrix4x4 subBottomRightVertex = QOpenGLTextureBlitter::targetTransform(subBottomRight, viewport, topLeftOrigin);
+
+    m_blitter.bind();
+    m_blitter.blit(texture.textureId(), subTopLeftVertex, texBottomRight);
+    m_blitter.blit(texture.textureId(), subTopRightVertex, texBottomLeft);
+    m_blitter.blit(texture.textureId(), subBottomLeftVertex, texTopRight);
+    m_blitter.blit(texture.textureId(), subBottomRightVertex, texTopLeft);
+
+    m_blitter.blit(texture.textureId(), topRightVertexFlipped, topLeftOrigin);
+    m_blitter.blit(texture.textureId(), bottomLeftVertex, bottomLeftOrigin);
+
+    m_blitter.setSwizzleRB(true);
+    m_blitter.blit(texture.textureId(), bottomRightVertexFlipped, texTopLeft);
+    m_blitter.setSwizzleRB(false);
+    m_blitter.release();
+
+    m_context->swapBuffers(this);
+}
+
+
+void QOpenGLTextureBlitWindow::exposeEvent(QExposeEvent *event)
+{
+    Q_UNUSED(event);
+    render();
+}
+
+void QOpenGLTextureBlitWindow::resizeEvent(QResizeEvent *event)
+{
+    Q_UNUSED(event);
+    m_image = QImage(size() * devicePixelRatio(), QImage::Format_ARGB32_Premultiplied);
+
+    m_image.fill(Qt::gray);
+
+    QPainter p(&m_image);
+
+    QPen pen(Qt::red);
+    pen.setWidth(5);
+    p.setPen(pen);
+
+    QFont font = p.font();
+    font.setPixelSize(qMin(m_image.height(), m_image.width()) / 20);
+    p.setFont(font);
+
+    int dx = dWidth() / 5;
+    int dy = dHeight() / 5;
+    for (int y = 0; y < 5; y++) {
+        for (int x = 0; x < 5; x++) {
+            QRect textRect(x * dx, y*dy, dx,dy);
+            QString text = QString("[%1,%2]").arg(x).arg(y);
+            p.drawText(textRect,text);
+        }
+    }
+
+    p.drawRect(QRectF(2.5,2.5,dWidth() - 5, dHeight() - 5));
+
+}
+