qquickopenglutils.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qquickopenglutils.h"
 
#include <QOpenGLContext>
#include <QOpenGLFunctions>
#include <QOpenGLFramebufferObject>
#include <private/qopenglvertexarrayobject_p.h>
 
QT_BEGIN_NAMESPACE
 
void QQuickOpenGLUtils::resetOpenGLState()
{
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    if (!ctx)
        return;
 
    QOpenGLFunctions *gl = ctx->functions();
 
    gl->glBindBuffer(GL_ARRAY_BUFFER, 0);
    gl->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 
    QOpenGLVertexArrayObjectHelper *vaoHelper = QOpenGLVertexArrayObjectHelper::vertexArrayObjectHelperForContext(ctx);
    if (vaoHelper->isValid())
        vaoHelper->glBindVertexArray(0);
 
    if (ctx->isOpenGLES() || (gl->openGLFeatures() & QOpenGLFunctions::FixedFunctionPipeline)) {
        int maxAttribs;
        gl->glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxAttribs);
        for (int i=0; i<maxAttribs; ++i) {
            gl->glVertexAttribPointer(i, 4, GL_FLOAT, GL_FALSE, 0, nullptr);
            gl->glDisableVertexAttribArray(i);
        }
    }
 
    gl->glActiveTexture(GL_TEXTURE0);
    gl->glBindTexture(GL_TEXTURE_2D, 0);
 
    gl->glDisable(GL_DEPTH_TEST);
    gl->glDisable(GL_STENCIL_TEST);
    gl->glDisable(GL_SCISSOR_TEST);
 
    gl->glColorMask(true, true, true, true);
    gl->glClearColor(0, 0, 0, 0);
 
    gl->glDepthMask(true);
    gl->glDepthFunc(GL_LESS);
    gl->glClearDepthf(1);
 
    gl->glStencilMask(0xff);
    gl->glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    gl->glStencilFunc(GL_ALWAYS, 0, 0xff);
 
    gl->glDisable(GL_BLEND);
    gl->glBlendFunc(GL_ONE, GL_ZERO);
 
    gl->glUseProgram(0);
 
    QOpenGLFramebufferObject::bindDefault();
}
 
QT_END_NAMESPACE