b8a70e62d5
At the moment, our frame scheduling infrastructure is still heavily based on Xinerama-style rendering. Specifically, we assume that painting is driven by a single timer, etc. This change introduces a new type - RenderLoop. Its main purpose is to drive compositing on a specific output, or in case of X11, on the overlay window. With RenderLoop, compositing is synchronized to vblank events. It exposes the last and the next estimated presentation timestamp. The expected presentation timestamp can be used by effects to ensure that animations are synchronized with the upcoming vblank event. On Wayland, every outputs has its own render loop. On X11, per screen rendering is not possible, therefore the platform exposes the render loop for the overlay window. Ideally, the Scene has to expose the RenderLoop, but as the first step towards better compositing scheduling it's good as is for the time being. The RenderLoop tries to minimize the latency by delaying compositing as close as possible to the next vblank event. One tricky thing about it is that if compositing is too close to the next vblank event, animations may become a little bit choppy. However, increasing the latency reduces the choppiness. Given that, there is no any "silver bullet" solution for the choppiness issue, a new option has been added in the Compositing KCM to specify the amount of latency. By default, it's "Medium," but if a user is not satisfied with the upstream default, they can tweak it.
131 lines
3.4 KiB
C++
131 lines
3.4 KiB
C++
/*
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KWin - the KDE window manager
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This file is part of the KDE project.
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SPDX-FileCopyrightText: 2020 Xaver Hugl <xaver.hugl@gmail.com>
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SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "egl_multi_backend.h"
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#include "logging.h"
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namespace KWin
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{
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EglMultiBackend::EglMultiBackend(AbstractEglDrmBackend *backend0) : OpenGLBackend()
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{
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m_backends.append(backend0);
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setIsDirectRendering(true);
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}
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EglMultiBackend::~EglMultiBackend()
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{
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for (int i = 1; i < m_backends.count(); i++) {
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delete m_backends[i];
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}
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// delete primary backend last, or this will crash!
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delete m_backends[0];
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}
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void EglMultiBackend::init()
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{
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for (auto b : qAsConst(m_backends)) {
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b->init();
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}
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// if any don't support it set it to not supported
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setSupportsBufferAge(true);
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setSupportsPartialUpdate(true);
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setSupportsSwapBuffersWithDamage(true);
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for (auto b : qAsConst(m_backends)) {
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if (!b->supportsBufferAge()) {
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setSupportsBufferAge(false);
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}
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if (!b->supportsPartialUpdate()) {
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setSupportsPartialUpdate(false);
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}
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if (!b->supportsSwapBuffersWithDamage()) {
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setSupportsSwapBuffersWithDamage(false);
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}
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}
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// we only care about the rendering GPU here
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setSupportsSurfacelessContext(m_backends[0]->supportsSurfacelessContext());
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// these are client extensions and the same for all egl backends
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setExtensions(m_backends[0]->extensions());
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m_backends[0]->makeCurrent();
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}
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QRegion EglMultiBackend::beginFrame(int screenId)
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{
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int internalScreenId;
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AbstractEglBackend *backend = findBackend(screenId, internalScreenId);
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Q_ASSERT(backend != nullptr);
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return backend->beginFrame(internalScreenId);
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}
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void EglMultiBackend::endFrame(int screenId, const QRegion &damage, const QRegion &damagedRegion)
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{
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int internalScreenId;
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AbstractEglBackend *backend = findBackend(screenId, internalScreenId);
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Q_ASSERT(backend != nullptr);
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backend->endFrame(internalScreenId, damage, damagedRegion);
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}
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bool EglMultiBackend::makeCurrent()
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{
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return m_backends[0]->makeCurrent();
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}
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void EglMultiBackend::doneCurrent()
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{
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m_backends[0]->doneCurrent();
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}
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SceneOpenGLTexturePrivate *EglMultiBackend::createBackendTexture(SceneOpenGLTexture *texture)
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{
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return m_backends[0]->createBackendTexture(texture);
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}
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QSharedPointer<GLTexture> EglMultiBackend::textureForOutput(AbstractOutput *requestedOutput) const
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{
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// this assumes that the wrong backends return {}
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for (auto backend : qAsConst(m_backends)) {
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auto texture = backend->textureForOutput(requestedOutput);
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if (!texture.isNull()) {
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return texture;
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}
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}
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return {};
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}
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bool EglMultiBackend::usesOverlayWindow() const
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{
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return false;
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}
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void EglMultiBackend::screenGeometryChanged(const QSize &size)
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{
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Q_UNUSED(size)
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}
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AbstractEglDrmBackend *EglMultiBackend::findBackend(int screenId, int& internalScreenId)
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{
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int screens = 0;
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for (int i = 0; i < m_backends.count(); i++) {
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if (screenId < screens + m_backends[i]->screenCount()) {
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internalScreenId = screenId - screens;
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return m_backends[i];
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}
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screens += m_backends[i]->screenCount();
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}
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qCDebug(KWIN_DRM) << "could not find backend!" << screenId << "/" << screens;
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return nullptr;
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}
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void EglMultiBackend::addBackend(AbstractEglDrmBackend *backend)
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{
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m_backends.append(backend);
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}
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}
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