Re: [Development] QtWayland compositor can't to render a wl_surface to multi outputs, Is this a restrict of QtQuick graphics scene?
Thank you.
Currently, my approach is to use a for loop to call
QQuickWindow::setRenderTarget to change the rendering target while change the
projectionMatrix of QSGRenderer.
"because different screens have different surface formats requirements"
Is point say a QSurfaceFormat? QSurface::format()? Does QRhi depend on it? I do
not find many using in QRhi, have some using in QRhiGles2::create.
"I know there have been talks of decoupling the Qt Quick graph from the window"
How to read those talks?
From: Eskil Abrahamsen Blomfeldt
Sent: Monday, July 10, 2023 17:38
To: JiDe Zhang ; Qt邮件列表
Subject: Re: QtWayland compositor can't to render a wl_surface to multi
outputs, Is this a restrict of QtQuick graphics scene?
Hi,
Each window has an isolated scene graph and RHI instance, which is the reason
for this limitation if I understand correctly. Decoupling them is actually
quite complicated, because different screens have different surface formats
requirements and it might not be possible to render to both screen within the
same context or to share graphics resources between them. These difficulties
are also why Wayland Compositor bases outputs on windows with isolated
graphics. I know there have been talks of decoupling the Qt Quick graph from
the window, so that the same Qt Quick code can control items in multiple
windows. There would still be separate graphics for the two windows and then
need for duplicate items, but synchronizing animations in that case should be
easier. Nothing concrete has come of this yet, though, but to me it sounds like
a more feasible way forwards than redesigning the Qt Quick scene graph.
In the current state, duplicating the items is the correct way to go, at least.
In order to make sure the animations are in sync, you could for instance have
some centralized property in a singleton which is read from both scenes and
just animate that. I think that's probably the easiest way.
Eskil Abrahamsen Blomfeldt
Senior Manager, Graphics
The Qt Company
Sandakerveien 116
0484 Oslo, Norway
eskil.abrahamsen-blomfe...@qt.io
http://qt.io
From: Development on behalf of JiDe Zhang
Sent: Tuesday, July 4, 2023 9:06 AM
To: Qt邮件列表
Subject: [Development] QtWayland compositor can't to render a wl_surface to
multi outputs, Is this a restrict of QtQuick graphics scene?
The following is a part of an QtWayland example:
WaylandOutput {
sizeFollowsWindow: true
window: Window {
width: 1024
height: 768
visible: true
Repeater {
model: shellSurfaces
ShellSurfaceItem {
shellSurface: modelData
onSurfaceDestroyed: shellSurfaces.remove(index)
}
}
}
}
If I have two displays, and a part of a ShellSurfaceItem is in the first
display, and the other part of the ShellSurfaceItem in the second display. In
this case, I need to ensure the user can see this ShellSurfaceItem
on both first and second displays, on QtWayland, I can using two WaylandOutput
with two Window for this case, and create ShellSurfaceItem for which
WaylandOutput.
But, If I using two ShellSurfaceItem for one wl_surface, I can't sync the
window animation in different WaylandOutput, this is a hard job, because the
QQuickItem must bind to single Window, it's can't render to multi Windows.
The better way is redesign QtQuick scene graphics, like as:
1. Add QQuickScene class to instead of a part of functions of QQuickWindow.
a QQuickItem must be added to a QQuickScene, a QQuickScene is a coordinate
system.
2. Add QQuickViewport class, and allow attach multi QQuickViewport to one
QQuickScene. the QQuickViewport be responsible for render QQuickItem to target
output. And allow the QQuickViewport can render in a new thread(be different
than the other QQuickViewport in same QQuickScene).
3. Add QQuickRenderTarget::fromSurface(EGLSurface/VkSurface) functions, and
using QQuickRenderTarget to QQuickViewport::render(QQuickRenderTarget target).
4. The QQuickWindow don't depends on QSG* class, it can wapper
QQuickViewport and QQuickRenderTarget to render QQuickItem.
5. Add QQuickSceneHelper abstract class, The QQuickWindow event dispense to
QQuickSceneHelper, and QQuickSceneHelper dispense event to QuickItem. Provide
like as "virtual QQuickSceneHelper::setCursor" functions to instead of
QQuickWindow::setCursor in QQuickItem::setCursor.
6. The QQuickItem without QQuickWindow, using QQuickItem::pixelRatio to
instead of QQuickWindow::effectiveDevicePixelRatio(), the
QQuickItem::pixelRatio is only using for load resources(like as
QQuickImage::load), for the render matrix, using the
QQuickViewport::devicePixelRatio when rendeing.
The above changes may not change the abi.
If I misunderstand QtWayalnd and
Re: [Development] QtWayland compositor can't to render a wl_surface to multi outputs, Is this a restrict of QtQuick graphics scene?
Hi,
Each window has an isolated scene graph and RHI instance, which is the reason
for this limitation if I understand correctly. Decoupling them is actually
quite complicated, because different screens have different surface formats
requirements and it might not be possible to render to both screen within the
same context or to share graphics resources between them. These difficulties
are also why Wayland Compositor bases outputs on windows with isolated
graphics. I know there have been talks of decoupling the Qt Quick graph from
the window, so that the same Qt Quick code can control items in multiple
windows. There would still be separate graphics for the two windows and then
need for duplicate items, but synchronizing animations in that case should be
easier. Nothing concrete has come of this yet, though, but to me it sounds like
a more feasible way forwards than redesigning the Qt Quick scene graph.
In the current state, duplicating the items is the correct way to go, at least.
In order to make sure the animations are in sync, you could for instance have
some centralized property in a singleton which is read from both scenes and
just animate that. I think that's probably the easiest way.
Eskil Abrahamsen Blomfeldt
Senior Manager, Graphics
The Qt Company
Sandakerveien 116
0484 Oslo, Norway
eskil.abrahamsen-blomfe...@qt.io
http://qt.io
From: Development on behalf of JiDe Zhang
Sent: Tuesday, July 4, 2023 9:06 AM
To: Qt邮件列表
Subject: [Development] QtWayland compositor can't to render a wl_surface to
multi outputs, Is this a restrict of QtQuick graphics scene?
The following is a part of an QtWayland example:
WaylandOutput {
sizeFollowsWindow: true
window: Window {
width: 1024
height: 768
visible: true
Repeater {
model: shellSurfaces
ShellSurfaceItem {
shellSurface: modelData
onSurfaceDestroyed: shellSurfaces.remove(index)
}
}
}
}
If I have two displays, and a part of a ShellSurfaceItem is in the first
display, and the other part of the ShellSurfaceItem in the second display. In
this case, I need to ensure the user can see this ShellSurfaceItem
on both first and second displays, on QtWayland, I can using two WaylandOutput
with two Window for this case, and create ShellSurfaceItem for which
WaylandOutput.
But, If I using two ShellSurfaceItem for one wl_surface, I can't sync the
window animation in different WaylandOutput, this is a hard job, because the
QQuickItem must bind to single Window, it's can't render to multi Windows.
The better way is redesign QtQuick scene graphics, like as:
1. Add QQuickScene class to instead of a part of functions of QQuickWindow.
a QQuickItem must be added to a QQuickScene, a QQuickScene is a coordinate
system.
2. Add QQuickViewport class, and allow attach multi QQuickViewport to one
QQuickScene. the QQuickViewport be responsible for render QQuickItem to target
output. And allow the QQuickViewport can render in a new thread(be different
than the other QQuickViewport in same QQuickScene).
3. Add QQuickRenderTarget::fromSurface(EGLSurface/VkSurface) functions, and
using QQuickRenderTarget to QQuickViewport::render(QQuickRenderTarget target).
4. The QQuickWindow don't depends on QSG* class, it can wapper
QQuickViewport and QQuickRenderTarget to render QQuickItem.
5. Add QQuickSceneHelper abstract class, The QQuickWindow event dispense to
QQuickSceneHelper, and QQuickSceneHelper dispense event to QuickItem. Provide
like as "virtual QQuickSceneHelper::setCursor" functions to instead of
QQuickWindow::setCursor in QQuickItem::setCursor.
6. The QQuickItem without QQuickWindow, using QQuickItem::pixelRatio to
instead of QQuickWindow::effectiveDevicePixelRatio(), the
QQuickItem::pixelRatio is only using for load resources(like as
QQuickImage::load), for the render matrix, using the
QQuickViewport::devicePixelRatio when rendeing.
The above changes may not change the abi.
If I misunderstand QtWayalnd and QtQuick Scene Graphics, please tell me, thanks.
--
Development mailing list
Development@qt-project.org
https://lists.qt-project.org/listinfo/development
[Development] QtWayland compositor can't to render a wl_surface to multi outputs, Is this a restrict of QtQuick graphics scene?
The following is a part of an QtWayland example:
WaylandOutput {
sizeFollowsWindow: true
window: Window {
width: 1024
height: 768
visible: true
Repeater {
model: shellSurfaces
ShellSurfaceItem {
shellSurface: modelData
onSurfaceDestroyed: shellSurfaces.remove(index)
}
}
}
}
If I have two displays, and a part of a ShellSurfaceItem is in the first
display, and the other part of the ShellSurfaceItem in the second display. In
this case, I need to ensure the user can see this ShellSurfaceItem
on both first and second displays, on QtWayland, I can using two WaylandOutput
with two Window for this case, and create ShellSurfaceItem for which
WaylandOutput.
But, If I using two ShellSurfaceItem for one wl_surface, I can't sync the
window animation in different WaylandOutput, this is a hard job, because the
QQuickItem must bind to single Window, it's can't render to multi Windows.
The better way is redesign QtQuick scene graphics, like as:
1. Add QQuickScene class to instead of a part of functions of QQuickWindow.
a QQuickItem must be added to a QQuickScene, a QQuickScene is a coordinate
system.
2. Add QQuickViewport class, and allow attach multi QQuickViewport to one
QQuickScene. the QQuickViewport be responsible for render QQuickItem to target
output. And allow the QQuickViewport can render in a new thread(be different
than the other QQuickViewport in same QQuickScene).
3. Add QQuickRenderTarget::fromSurface(EGLSurface/VkSurface) functions, and
using QQuickRenderTarget to QQuickViewport::render(QQuickRenderTarget target).
4. The QQuickWindow don't depends on QSG* class, it can wapper
QQuickViewport and QQuickRenderTarget to render QQuickItem.
5. Add QQuickSceneHelper abstract class, The QQuickWindow event dispense to
QQuickSceneHelper, and QQuickSceneHelper dispense event to QuickItem. Provide
like as "virtual QQuickSceneHelper::setCursor" functions to instead of
QQuickWindow::setCursor in QQuickItem::setCursor.
6. The QQuickItem without QQuickWindow, using QQuickItem::pixelRatio to
instead of QQuickWindow::effectiveDevicePixelRatio(), the
QQuickItem::pixelRatio is only using for load resources(like as
QQuickImage::load), for the render matrix, using the
QQuickViewport::devicePixelRatio when rendeing.
The above changes may not change the abi.
If I misunderstand QtWayalnd and QtQuick Scene Graphics, please tell me, thanks.
--
Development mailing list
Development@qt-project.org
https://lists.qt-project.org/listinfo/development
