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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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 http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/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 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "squircle.h"
#include <QtQuick/qquickwindow.h>
#include <QtGui/QOpenGLShaderProgram>
#include <QtGui/QOpenGLContext>
//! [7]
Squircle::Squircle()
: m_t(0)
, m_renderer(0)
{
connect(this, &QQuickItem::windowChanged, this, &Squircle::handleWindowChanged);
}
//! [7]
//! [8]
void Squircle::setT(qreal t)
{
if (t == m_t)
return;
m_t = t;
emit tChanged();
if (window())
window()->update();
}
//! [8]
//! [1]
void Squircle::handleWindowChanged(QQuickWindow *win)
{
if (win) {
connect(win, &QQuickWindow::beforeSynchronizing, this, &Squircle::sync, Qt::DirectConnection);
connect(win, &QQuickWindow::sceneGraphInvalidated, this, &Squircle::cleanup, Qt::DirectConnection);
//! [1]
// If we allow QML to do the clearing, they would clear what we paint
// and nothing would show.
//! [3]
win->setClearBeforeRendering(false);
}
}
//! [3]
//! [6]
void Squircle::cleanup()
{
if (m_renderer) {
delete m_renderer;
m_renderer = 0;
}
}
SquircleRenderer::~SquircleRenderer()
{
delete m_program;
}
//! [6]
//! [9]
void Squircle::sync()
{
if (!m_renderer) {
m_renderer = new SquircleRenderer();
connect(window(), &QQuickWindow::beforeRendering, m_renderer, &SquircleRenderer::paint, Qt::DirectConnection);
}
m_renderer->setViewportSize(window()->size() * window()->devicePixelRatio());
m_renderer->setT(m_t);
m_renderer->setWindow(window());
}
//! [9]
//! [4]
void SquircleRenderer::paint()
{
if (!m_program) {
initializeOpenGLFunctions();
m_program = new QOpenGLShaderProgram();
m_program->addShaderFromSourceCode(QOpenGLShader::Vertex,
"attribute highp vec4 vertices;"
"varying highp vec2 coords;"
"void main() {"
" gl_Position = vertices;"
" coords = vertices.xy;"
"}");
m_program->addShaderFromSourceCode(QOpenGLShader::Fragment,
"uniform lowp float t;"
"varying highp vec2 coords;"
"void main() {"
" lowp float i = 1. - (pow(abs(coords.x), 4.) + pow(abs(coords.y), 4.));"
" i = smoothstep(t - 0.8, t + 0.8, i);"
" i = floor(i * 20.) / 20.;"
" gl_FragColor = vec4(coords * .5 + .5, i, i);"
"}");
m_program->bindAttributeLocation("vertices", 0);
m_program->link();
}
//! [4] //! [5]
m_program->bind();
m_program->enableAttributeArray(0);
float values[] = {
-1, -1,
1, -1,
-1, 1,
1, 1
};
m_program->setAttributeArray(0, GL_FLOAT, values, 2);
m_program->setUniformValue("t", (float) m_t);
glViewport(0, 0, m_viewportSize.width(), m_viewportSize.height());
glDisable(GL_DEPTH_TEST);
glClearColor(0, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
m_program->disableAttributeArray(0);
m_program->release();
// Not strictly needed for this example, but generally useful for when
// mixing with raw OpenGL.
m_window->resetOpenGLState();
}
//! [5]
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