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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "squircle.h"
#include <QtQuick/qquickwindow.h>
#include <QOpenGLShaderProgram>
#include <QOpenGLContext>
#include <QtCore/QRunnable>
//! [7]
Squircle::Squircle()
: m_t(0)
, m_renderer(nullptr)
{
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]
//! [3]
// Ensure we start with cleared to black. The squircle's blend mode relies on this.
win->setColor(Qt::black);
}
}
//! [3]
//! [6]
void Squircle::cleanup()
{
delete m_renderer;
m_renderer = nullptr;
}
class CleanupJob : public QRunnable
{
public:
CleanupJob(SquircleRenderer *renderer) : m_renderer(renderer) { }
void run() override { delete m_renderer; }
private:
SquircleRenderer *m_renderer;
};
void Squircle::releaseResources()
{
window()->scheduleRenderJob(new CleanupJob(m_renderer), QQuickWindow::BeforeSynchronizingStage);
m_renderer = nullptr;
}
SquircleRenderer::~SquircleRenderer()
{
delete m_program;
}
//! [6]
//! [9]
void Squircle::sync()
{
if (!m_renderer) {
m_renderer = new SquircleRenderer();
connect(window(), &QQuickWindow::beforeRendering, m_renderer, &SquircleRenderer::init, Qt::DirectConnection);
connect(window(), &QQuickWindow::beforeRenderPassRecording, 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::init()
{
if (!m_program) {
QSGRendererInterface *rif = m_window->rendererInterface();
Q_ASSERT(rif->graphicsApi() == QSGRendererInterface::OpenGL);
initializeOpenGLFunctions();
const float values[] = { -1, -1, 1, -1, -1, 1, 1, 1 };
m_vbo.create();
m_vbo.bind();
m_vbo.allocate(values, sizeof(values));
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), nullptr);
m_program = new QOpenGLShaderProgram();
m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex,
"attribute highp vec4 vertices;"
"varying highp vec2 coords;"
"void main() {"
" gl_Position = vertices;"
" coords = vertices.xy;"
"}");
m_program->addCacheableShaderFromSourceCode(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]
void SquircleRenderer::paint()
{
// Play nice with the RHI. Not strictly needed when the scenegraph uses
// OpenGL directly.
m_window->beginExternalCommands();
m_vbo.bind();
m_program->bind();
m_program->setUniformValue("t", (float)m_t);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), nullptr);
glViewport(0, 0, m_viewportSize.width(), m_viewportSize.height());
glDisable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDisableVertexAttribArray(0);
m_program->release();
m_window->endExternalCommands();
}
//! [5]
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