qt-everywhere-src-5.14.1/qtquick3d/tests/manual/render/shared/renderexample.cpp

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#include "renderexample.h"
#include <QtQuick3DRender/private/qssgrenderbasetypes_p.h>

#include <cstring>
#include <cstdio>
#include <cstdlib>

#include <cmath>

#include <QtGui/QSurfaceFormat>

QSSGRenderExample::QSSGRenderExample(QWindow *parent)
    : QWindow(parent)
{
    setSurfaceType(QWindow::OpenGLSurface);
    setWidth(1280);
    setHeight(720);
    m_frameTimer.start();
}

QSSGRenderExample::~QSSGRenderExample()
{
    delete m_context;
}

void QSSGRenderExample::renderLater()
{
    requestUpdate();
}

void QSSGRenderExample::renderNow()
{
    if (!m_isIntialized) {
        preInit();
        initialize();
        m_isIntialized = true;
    }
    m_context->makeCurrent(this);
    drawFrame(m_frameTimer.elapsed());
    m_frameTimer.restart();
    m_context->swapBuffers(this);
    m_context->doneCurrent();
    if (m_autoUpdate)
        renderLater();
}

bool QSSGRenderExample::event(QEvent *event)
{
    switch (event->type()) {
    case QEvent::UpdateRequest:
        renderNow();
        return true;
    default:
        return QWindow::event(event);
    }
}

void QSSGRenderExample::exposeEvent(QExposeEvent *event)
{
    Q_UNUSED(event);

    if (isExposed())
        renderNow();
}

void QSSGRenderExample::preInit()
{
    m_context = new QOpenGLContext();
    m_context->setFormat(requestedFormat());
    m_context->create();

    if (!m_context->makeCurrent(this))
        qDebug("fail");
}


// Math stuff

int eq(float a, float b)
{
    float diff = a - b;
    if (diff < 0) {
        diff = -diff;
    }
    return diff <= eps;
}