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/****************************************************************************
**
** Copyright (C) 2018 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qwasmopenglcontext.h"
#include "qwasmintegration.h"
#include <EGL/egl.h>
QT_BEGIN_NAMESPACE
QWasmOpenGLContext::QWasmOpenGLContext(const QSurfaceFormat &format)
: m_requestedFormat(format)
{
m_requestedFormat.setRenderableType(QSurfaceFormat::OpenGLES);
// if we set one, we need to set the other as well since in webgl, these are tied together
if (format.depthBufferSize() < 0 && format.stencilBufferSize() > 0)
m_requestedFormat.setDepthBufferSize(16);
if (format.stencilBufferSize() < 0 && format.depthBufferSize() > 0)
m_requestedFormat.setStencilBufferSize(8);
}
QWasmOpenGLContext::~QWasmOpenGLContext()
{
if (m_context) {
emscripten_webgl_destroy_context(m_context);
m_context = 0;
}
}
bool QWasmOpenGLContext::maybeCreateEmscriptenContext(QPlatformSurface *surface)
{
// Native emscripten/WebGL contexts are tied to a single screen/canvas. The first
// call to this function creates a native canvas for the given screen, subsequent
// calls verify that the surface is on/off the same screen.
QPlatformScreen *screen = surface->screen();
if (m_context && !screen)
return false; // Alternative: return true to support makeCurrent on QOffScreenSurface with
// no screen. However, Qt likes to substitute QGuiApplication::primaryScreen()
// for null screens, which foils this plan.
if (!screen)
return false;
if (m_context)
return m_screen == screen;
QString canvasId = QWasmScreen::get(screen)->canvasId();
m_context = createEmscriptenContext(canvasId, m_requestedFormat);
m_screen = screen;
return true;
}
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE QWasmOpenGLContext::createEmscriptenContext(const QString &canvasId, QSurfaceFormat format)
{
EmscriptenWebGLContextAttributes attributes;
emscripten_webgl_init_context_attributes(&attributes); // Populate with default attributes
attributes.preferLowPowerToHighPerformance = false;
attributes.failIfMajorPerformanceCaveat = false;
attributes.antialias = true;
attributes.enableExtensionsByDefault = true;
if (format.majorVersion() == 3) {
attributes.majorVersion = 2;
}
// WebGL doesn't allow separate attach buffers to STENCIL_ATTACHMENT and DEPTH_ATTACHMENT
// we need both or none
bool useDepthStencil = (format.depthBufferSize() > 0 || format.stencilBufferSize() > 0);
// WebGL offers enable/disable control but not size control for these
attributes.alpha = format.alphaBufferSize() > 0;
attributes.depth = useDepthStencil;
attributes.stencil = useDepthStencil;
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(canvasId.toLocal8Bit().constData(), &attributes);
return context;
}
QSurfaceFormat QWasmOpenGLContext::format() const
{
return m_requestedFormat;
}
GLuint QWasmOpenGLContext::defaultFramebufferObject(QPlatformSurface *surface) const
{
return QPlatformOpenGLContext::defaultFramebufferObject(surface);
}
bool QWasmOpenGLContext::makeCurrent(QPlatformSurface *surface)
{
bool ok = maybeCreateEmscriptenContext(surface);
if (!ok)
return false;
return emscripten_webgl_make_context_current(m_context) == EMSCRIPTEN_RESULT_SUCCESS;
}
void QWasmOpenGLContext::swapBuffers(QPlatformSurface *surface)
{
Q_UNUSED(surface);
// No swapbuffers on WebGl
}
void QWasmOpenGLContext::doneCurrent()
{
// No doneCurrent on WebGl
}
bool QWasmOpenGLContext::isSharing() const
{
return false;
}
bool QWasmOpenGLContext::isValid() const
{
// Note: we get isValid() calls before we see the surface and can
// create a native context, so no context is also a valid state.
return !m_context || !emscripten_is_webgl_context_lost(m_context);
}
QFunctionPointer QWasmOpenGLContext::getProcAddress(const char *procName)
{
return reinterpret_cast<QFunctionPointer>(eglGetProcAddress(procName));
}
QT_END_NAMESPACE
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