Differential D4366 Diff 10760 effects/screencast/screencast.cpp

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effects/screencast/screencast.cpp

  • This file was added.
1​#include "screencast.h"
2​#include <QDBusConnection>
3​#include <QThread>
4​#include <QWeakPointer>
5​
6​#include <KWayland/Client/compositor.h>
7​#include <KWayland/Client/registry.h>
8​#include <KWayland/Client/shm_pool.h>
9​
10​#include <kwinglutils.h>
11​#include <kwinglplatform.h>
12​
13​const static QString s_errorAlreadyTaking = QStringLiteral("org.kde.kwin.Screenshot.Error.AlreadyTaking");
14​const static QString s_errorAlreadyTakingMsg = QStringLiteral("A screencast is already been taken");
15​const static QString s_errorFailed = QStringLiteral("org.kde.kwin.Screencast.Error.Failed");
16​const static QString s_errorFailedMsg = QStringLiteral("Could not connect to recording server");
17​
18​
19​using namespace KWayland::Client;
20​using namespace KWin;
21​
22​ScreenCastEffect::ScreenCastEffect()
23​{
24​ QDBusConnection::sessionBus().registerObject(QStringLiteral("/Screencast"), this, QDBusConnection::ExportScriptableContents);
25​}
26​
27​ScreenCastEffect::~ScreenCastEffect()
28​{
29​}
30​
31​bool ScreenCastEffect::isActive() const
32​{
33​ return m_active;
34​}
35​
36​void ScreenCastEffect::screencast(const QString &socket)
37​{
38​ if (m_active == true) {
39​ sendErrorReply(s_errorAlreadyTaking, s_errorAlreadyTakingMsg);
40​ return;
41​ }
42​ m_active = true;
43​ setDelayedReply(true);
44​ m_message = message();
45​
46​ //designed so deleteing this object should remove all wayland client related objects
47​ auto connectionThreadThread = new QThread(this);
48​
49​ auto connectionThread = new ConnectionThread(0);
50​ connect(connectionThreadThread, &QObject::destroyed, connectionThread, &QObject::deleteLater);
51​ connectionThread->moveToThread(connectionThreadThread);
52​
53​ connect(connectionThreadThread, &QThread::started, connectionThread, [=]() {
54​ qDebug() << "trying to connect";
55​ connectionThread->setSocketName(socket);
56​ connectionThread->initConnection();
57​ });
58​
59​ connect(connectionThread, &ConnectionThread::connected, this, [=]() {
60​ auto registry = new Registry(connectionThreadThread);
61​ registry->create(connectionThread);
62​
63​ //return a non-error to show we've connected
64​ QDBusConnection::sessionBus().send(m_message.createReply());
65​
66​ connect(registry, &Registry::compositorAnnounced, this, [registry, this](qint32 name, qint32 version) {
67​ auto compositor = registry->createCompositor(name, version, registry);
68​ m_surface = compositor->createSurface();
69​ });
70​
71​ connect(registry, &Registry::shmAnnounced, this, [registry, this](qint32 name, qint32 version) {
72​ m_pool = registry->createShmPool(name, version, registry);
73​ });
74​
75​ registry->setup();
76​ });
77​
78​ connect(connectionThread, &ConnectionThread::connectionDied, this, [=]() {
79​ m_active = false;
80​ delete connectionThreadThread;
81​ });
82​
83​ connect(connectionThread, &ConnectionThread::failed, this, [=]() {
84​ m_active = false;
85​ delete connectionThreadThread;
86​ sendErrorReply(s_errorFailed, s_errorFailedMsg);
87​ });
88​
89​ connectionThreadThread->start();
90​}
91​
92​void ScreenCastEffect::postPaintScreen()
93​{
94​ if (!m_surface || !m_pool) {
95​ //nothing active. skip
96​ return;
97​ }
98​
99​ qDebug() << "committing new image";
100​
101​ //FIXME this assumes one screen
102​ //TODO buffer everything up like screenshot into a single buffer
103​ //or we could return one surface per screen..but we'd need a custom interface to communicate positions?
104​
105​ QRect geometry = effects->virtualScreenGeometry();
fredrikUnsubmitted
Not Done

I strongly suggest that you use the damage information from kwin and only download the parts of the framebuffer that have actually changed. This can make a massive difference in performance.

You can keep a screen sized QImage around and keep it in sync by updating areas as they change.

fredrik: I strongly suggest that you use the damage information from kwin and only download the parts of…
106​
107​ GLTexture tex(GL_RGBA8, geometry.width(), geometry.height());
fredrikUnsubmitted
Not Done

Why do you use an intermediate texture instead of reading directly from the framebuffer in the desktop GL case?

You create the texture and blit the framebuffer into it in the GLES case, even though you don't use it.

fredrik: Why do you use an intermediate texture instead of reading directly from the framebuffer in the…
108​ GLRenderTarget target(tex);
109​ target.blitFromFramebuffer(geometry);
fredrikUnsubmitted
Not Done

There is no need to use a RenderTarget here. Use glCopyTexSubImage2D() instead, which copies from the framebuffer to the currently bound texture.

fredrik: There is no need to use a RenderTarget here. Use glCopyTexSubImage2D() instead, which copies…
110​
111​ // copy content from framebuffer into image
112​ tex.bind();
113​
114​ auto img = QImage(geometry.size(), QImage::Format_RGB888);
fredrikUnsubmitted
Not Done

Don't read back data directly to client memory. Instead create a GL_PIXEL_PACK_BUFFER and download the image into it. That way glReadPixels()/glGetTexImage() schedules the copy, but doesn't block and wait for it to finish. Wait at least one frame before you access the contents of the buffer.

fredrik: Don't read back data directly to client memory. Instead create a GL_PIXEL_PACK_BUFFER and…
115​ if (GLPlatform::instance()->isGLES()) {
116​ glReadPixels(0, 0, img.width(), img.height(), GL_RGB, GL_UNSIGNED_BYTE, (GLvoid*)img.bits());
fredrikUnsubmitted
Not Done

Never read back data as GL_RGB. Three component formats are not supported in hardware, so this involves at least a partial software fallback.

The only format/type combination a GLES implementation is required to support is also GL_RGBA/GL_UNSIGNED_BYTE.

I also note that you immediately convert the image to a four-component format below.

fredrik: Never read back data as GL_RGB. Three component formats are not supported in hardware, so this…
117​ } else {
118​ glGetTexImage(GL_TEXTURE_2D, 0, GL_RGB, GL_UNSIGNED_BYTE, (GLvoid*)img.bits());
fredrikUnsubmitted
Not Done

If you need the image to be in QImage::Format_ARGB32, you should read back the data as GL_BGRA/GL_UNSIGNED_INT_8_8_8_8_REV. This is the GL equivalent of QImage::Format_ARGB32.

fredrik: If you need the image to be in QImage::Format_ARGB32, you should read back the data as…
119​ }
120​ img = img.convertToFormat(QImage::Format_ARGB32);
121​ img = img.mirrored();
fredrikUnsubmitted
Not Done

Use GL_MESA_pack_invert and GL_ANGLE_pack_reverse_row_order so the image is downloaded in the correct orientation.

fredrik: Use GL_MESA_pack_invert and GL_ANGLE_pack_reverse_row_order so the image is downloaded in the…
122​ tex.unbind();
123​
124​ auto buffer = m_pool->createBuffer(img);
125​ m_surface->attachBuffer(buffer);
126​ m_surface->damage(geometry); //TODO: in theory we know what area of the screen is damaged, but I can't access it, unless I buffer all regions called in the paintEvent
127​ m_surface->commit(Surface::CommitFlag::None);
128​}
129​
130​bool ScreenCastEffect::supported()
131​{
132​ return effects->isOpenGLCompositing() && GLRenderTarget::supported();
133​}