1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the demonstration applications of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:BSD$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** BSD License Usage
18** Alternatively, you may use this file under the terms of the BSD license
19** as follows:
20**
21** "Redistribution and use in source and binary forms, with or without
22** modification, are permitted provided that the following conditions are
23** met:
24** * Redistributions of source code must retain the above copyright
25** notice, this list of conditions and the following disclaimer.
26** * Redistributions in binary form must reproduce the above copyright
27** notice, this list of conditions and the following disclaimer in
28** the documentation and/or other materials provided with the
29** distribution.
30** * Neither the name of The Qt Company Ltd nor the names of its
31** contributors may be used to endorse or promote products derived
32** from this software without specific prior written permission.
33**
34**
35** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
36** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
37** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
38** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
39** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
42** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
43** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
44** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
45** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
46**
47** $QT_END_LICENSE$
48**
49****************************************************************************/
50
51#include "squircle.h"
52
53#include <QtQuick/qquickwindow.h>
54#include <QtGui/QOpenGLShaderProgram>
55#include <QtGui/QOpenGLContext>
56#include <QtCore/QRunnable>
57
58//! [7]
59Squircle::Squircle()
60 : m_t(0)
61 , m_renderer(nullptr)
62{
63 connect(sender: this, signal: &QQuickItem::windowChanged, receiver: this, slot: &Squircle::handleWindowChanged);
64}
65//! [7]
66
67//! [8]
68void Squircle::setT(qreal t)
69{
70 if (t == m_t)
71 return;
72 m_t = t;
73 emit tChanged();
74 if (window())
75 window()->update();
76}
77//! [8]
78
79//! [1]
80void Squircle::handleWindowChanged(QQuickWindow *win)
81{
82 if (win) {
83 connect(sender: win, signal: &QQuickWindow::beforeSynchronizing, receiver: this, slot: &Squircle::sync, type: Qt::DirectConnection);
84 connect(sender: win, signal: &QQuickWindow::sceneGraphInvalidated, receiver: this, slot: &Squircle::cleanup, type: Qt::DirectConnection);
85//! [1]
86//! [3]
87 // Ensure we start with cleared to black. The squircle's blend mode relies on this.
88 win->setColor(Qt::black);
89 }
90}
91//! [3]
92
93//! [6]
94void Squircle::cleanup()
95{
96 delete m_renderer;
97 m_renderer = nullptr;
98}
99
100class CleanupJob : public QRunnable
101{
102public:
103 CleanupJob(SquircleRenderer *renderer) : m_renderer(renderer) { }
104 void run() override { delete m_renderer; }
105private:
106 SquircleRenderer *m_renderer;
107};
108
109void Squircle::releaseResources()
110{
111 window()->scheduleRenderJob(job: new CleanupJob(m_renderer), schedule: QQuickWindow::BeforeSynchronizingStage);
112 m_renderer = nullptr;
113}
114
115SquircleRenderer::~SquircleRenderer()
116{
117 delete m_program;
118}
119//! [6]
120
121//! [9]
122void Squircle::sync()
123{
124 if (!m_renderer) {
125 m_renderer = new SquircleRenderer();
126 connect(sender: window(), signal: &QQuickWindow::beforeRendering, receiver: m_renderer, slot: &SquircleRenderer::init, type: Qt::DirectConnection);
127 connect(sender: window(), signal: &QQuickWindow::beforeRenderPassRecording, receiver: m_renderer, slot: &SquircleRenderer::paint, type: Qt::DirectConnection);
128 }
129 m_renderer->setViewportSize(window()->size() * window()->devicePixelRatio());
130 m_renderer->setT(m_t);
131 m_renderer->setWindow(window());
132}
133//! [9]
134
135//! [4]
136void SquircleRenderer::init()
137{
138 if (!m_program) {
139 QSGRendererInterface *rif = m_window->rendererInterface();
140 Q_ASSERT(rif->graphicsApi() == QSGRendererInterface::OpenGL || rif->graphicsApi() == QSGRendererInterface::OpenGLRhi);
141
142 initializeOpenGLFunctions();
143
144 m_program = new QOpenGLShaderProgram();
145 m_program->addCacheableShaderFromSourceCode(type: QOpenGLShader::Vertex,
146 source: "attribute highp vec4 vertices;"
147 "varying highp vec2 coords;"
148 "void main() {"
149 " gl_Position = vertices;"
150 " coords = vertices.xy;"
151 "}");
152 m_program->addCacheableShaderFromSourceCode(type: QOpenGLShader::Fragment,
153 source: "uniform lowp float t;"
154 "varying highp vec2 coords;"
155 "void main() {"
156 " lowp float i = 1. - (pow(abs(coords.x), 4.) + pow(abs(coords.y), 4.));"
157 " i = smoothstep(t - 0.8, t + 0.8, i);"
158 " i = floor(i * 20.) / 20.;"
159 " gl_FragColor = vec4(coords * .5 + .5, i, i);"
160 "}");
161
162 m_program->bindAttributeLocation(name: "vertices", location: 0);
163 m_program->link();
164
165 }
166}
167
168//! [4] //! [5]
169void SquircleRenderer::paint()
170{
171 // Play nice with the RHI. Not strictly needed when the scenegraph uses
172 // OpenGL directly.
173 m_window->beginExternalCommands();
174
175 m_program->bind();
176
177 m_program->enableAttributeArray(location: 0);
178
179 float values[] = {
180 -1, -1,
181 1, -1,
182 -1, 1,
183 1, 1
184 };
185
186 // This example relies on (deprecated) client-side pointers for the vertex
187 // input. Therefore, we have to make sure no vertex buffer is bound.
188 glBindBuffer(GL_ARRAY_BUFFER, buffer: 0);
189
190 m_program->setAttributeArray(location: 0, GL_FLOAT, values, tupleSize: 2);
191 m_program->setUniformValue(name: "t", value: (float) m_t);
192
193 glViewport(x: 0, y: 0, width: m_viewportSize.width(), height: m_viewportSize.height());
194
195 glDisable(GL_DEPTH_TEST);
196
197 glEnable(GL_BLEND);
198 glBlendFunc(GL_SRC_ALPHA, GL_ONE);
199
200 glDrawArrays(GL_TRIANGLE_STRIP, first: 0, count: 4);
201
202 m_program->disableAttributeArray(location: 0);
203 m_program->release();
204
205 // Not strictly needed for this example, but generally useful for when
206 // mixing with raw OpenGL.
207 m_window->resetOpenGLState();
208
209 m_window->endExternalCommands();
210}
211//! [5]
212

source code of qtdeclarative/examples/quick/scenegraph/openglunderqml/squircle.cpp