Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[Sean Harmer]

On Sunday 01 May 2016 09:15:52 Sean Harmer wrote:
> On 30/04/2016 21:02, Pierre Chicoine wrote:
> > Thank you Sean. Very descriptive.   Since I have such a large system,
> > I will create an example and pass it to you.
> > 
> > By the way a large percentage of your examples on 5.7 beta don't work.
> > But I'm sure you're aware of that.
> 
> Yup, we're replacing something at the moment. Lots of commits lined up
> but the CI is broken.

I have fixes for almost all of the issues in the examples, locally now. Will 
push and merge as soon as I can.

Cheers,

Sean

> 
> Sean
> 
> > Thank you again.
> > 
> > On Apr 30, 2016 10:55 AM, "Sean Harmer"  > 
> > > wrote:
> > > Hi,
> > > 
> > > There's two things you need to consider:
> > > 
> > > 1) The scene graph - the Entities that you wish to draw.
> > > 2) The framegraph - specifies the algorithm used to draw the scene graph
> > > 
> > > I assume from your screenshot that you are more or less happy with
> > 
> > defining
> > 
> > > QEntity's to construct your scene graph. If you wish some entities
> > 
> > to be drawn
> > 
> > > in one part of the window (viewport) and the others in another
> > 
> > viewport then
> > 
> > > we need some way of saying "select this set of entities but not that
> > 
> > set".
> > 
> > > One way of doing this is by using a QLayer component attached to
> > 
> > your entities
> > 
> > > that says which layer that entity is part of. This is just like layers
> > > photoshop, gimp, blender etc. Create a QLayer, give it a name, and
> > 
> > aggregate
> > 
> > > it onto your QEntity as you do the other components (mesh, transform and
> > > material).
> > > 
> > > Doing this doesn't change anything in the rendering on it's own. To
> > 
> > affect the
> > 
> > > change we also need to modify the framegraph. To do this, make sure the
> > > concept of the framegraph is clear in your mind. Have a read of:
> > > 
> > > https://www.kdab.com/qt3d-2-0-framegraph/
> > > 
> > > Each leaf node, corresponds to a portion of your overall scene. To
> > 
> > keep things
> > 
> > > simple, lets only consider the viewports and layer filters you will
> > 
> > need. You
> > 
> > > will need other things in the framegraph too (rendersurfaceselector
> > 
> > (if using
> > 
> > > 5.7), camera selector, technique selector etc). The parts of the
> > 
> > framegraph
> > 
> > > concerned with viewports and layers will look something like this:
> > > 
> > > Root (e.g. TechniqueSelector)
> > > 
> > > |- Viewport [left half of window]
> > > |
> > > |- LayerFilter [names="layer1"] (*)
> > > |
> > > |- Viewport [right half of window]
> > > |
> > > |- LayerFilter [names="layer2"] (**)
> > > 
> > > Where:
> > > 
> > > (*) <-- draws entities on "layer1" in left viewport
> > > (**) <-- draws entities on "layer2" in right viewport
> > > 
> > > If you then want to use different cameras in the different viewports
> > 
> > then you
> > 
> > > can include a QCameraSelector node in each sub-tree.
> > > 
> > > Root (e.g. TechniqueSelector)
> > > 
> > > |- Viewport [left half of window]
> > > |
> > > |- CameraSelector [camera1]
> > > |
> > > |- LayerFilter [names="layer1"] (*)
> > > |
> > > |- Viewport [right half of window]
> > > |
> > > |- CameraSelector [camera2]
> > > |
> > > |- LayerFilter [names="layer2"] (**)
> > > 
> > > Where:
> > > 
> > > (*) <-- draws entities on "layer1" in left viewport using "camera1"
> > > (**) <-- draws entities on "layer2" in right viewport using "camera2"
> > > 
> > > Hopefully that makes sense. In the future, I hope we can provide
> > 
> > tooling and
> > 
> > > perhaps higher level ways of building custom framegraphs. The
> > 
> > framegraph is
> > 
> > > hugely powerful as it totally allows changing the rendering algorithm at
> > > runtime without having to touch low level C++ graphics code.
> > 
> > However, it is a
> > 
> > > bit tricky to get to grips with at first.
> > > 
> > > Cheers,
> > > 
> > > Sean
> > > 
> > > On Thursday 28 April 2016 13:34:58 Pierre Chicoine wrote:
> > > > Dear Sirs
> > > > 
> > > > First: Thank you for Qt3d. The KDAB people are heroes in my book.
> > > > 
> > > > I have two problems in C++ Qt3D.
> > > > 
> > > > 1. I am having a difficult time figuring out how to render
> > 
> > QEntities into
> > 
> > > > separate QViewports. All my 3d objects draw to the first
> > 
> > QViewport, the
> > 
> > > > rest are black. I have read all your articles and comments
> > 
> > everywhere on
> > 
> > > > the Internet that I can find and I am basically confused.
> > > > 
> > > > Is there a c++ example that would show multiple viewports with
> > 
> > distinct
> > 
> > > > separate QEntities? I can't seem to duplicate The QML example
> > 
> > multiviewport
> > 
> > > > in my code. What classes would get me there?
> > > > 
> > > > 2. Also I'm also confused about QNodes and QEntitys and their
> > > > relationships. Maybe it's the use of Qt3d 

Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[Sean Harmer]

On 30/04/2016 21:02, Pierre Chicoine wrote:


Thank you Sean. Very descriptive.   Since I have such a large system, 
I will create an example and pass it to you.


By the way a large percentage of your examples on 5.7 beta don't work. 
But I'm sure you're aware of that.




Yup, we're replacing something at the moment. Lots of commits lined up 
but the CI is broken.


Sean


Thank you again.

On Apr 30, 2016 10:55 AM, "Sean Harmer" > wrote:

>
> Hi,
>
> There's two things you need to consider:
>
> 1) The scene graph - the Entities that you wish to draw.
> 2) The framegraph - specifies the algorithm used to draw the scene graph
>
> I assume from your screenshot that you are more or less happy with 
defining
> QEntity's to construct your scene graph. If you wish some entities 
to be drawn
> in one part of the window (viewport) and the others in another 
viewport then
> we need some way of saying "select this set of entities but not that 
set".

>
> One way of doing this is by using a QLayer component attached to 
your entities

> that says which layer that entity is part of. This is just like layers
> photoshop, gimp, blender etc. Create a QLayer, give it a name, and 
aggregate

> it onto your QEntity as you do the other components (mesh, transform and
> material).
>
> Doing this doesn't change anything in the rendering on it's own. To 
affect the

> change we also need to modify the framegraph. To do this, make sure the
> concept of the framegraph is clear in your mind. Have a read of:
>
> https://www.kdab.com/qt3d-2-0-framegraph/
>
> Each leaf node, corresponds to a portion of your overall scene. To 
keep things
> simple, lets only consider the viewports and layer filters you will 
need. You
> will need other things in the framegraph too (rendersurfaceselector 
(if using
> 5.7), camera selector, technique selector etc). The parts of the 
framegraph

> concerned with viewports and layers will look something like this:
>
> Root (e.g. TechniqueSelector)
> |- Viewport [left half of window]
> |- LayerFilter [names="layer1"] (*)
> |- Viewport [right half of window]
> |- LayerFilter [names="layer2"] (**)
>
> Where:
>
> (*) <-- draws entities on "layer1" in left viewport
> (**) <-- draws entities on "layer2" in right viewport
>
> If you then want to use different cameras in the different viewports 
then you

> can include a QCameraSelector node in each sub-tree.
>
> Root (e.g. TechniqueSelector)
> |- Viewport [left half of window]
> |- CameraSelector [camera1]
> |- LayerFilter [names="layer1"] (*)
> |- Viewport [right half of window]
> |- CameraSelector [camera2]
> |- LayerFilter [names="layer2"] (**)
>
> Where:
>
> (*) <-- draws entities on "layer1" in left viewport using "camera1"
> (**) <-- draws entities on "layer2" in right viewport using "camera2"
>
> Hopefully that makes sense. In the future, I hope we can provide 
tooling and
> perhaps higher level ways of building custom framegraphs. The 
framegraph is

> hugely powerful as it totally allows changing the rendering algorithm at
> runtime without having to touch low level C++ graphics code. 
However, it is a

> bit tricky to get to grips with at first.
>
> Cheers,
>
> Sean
>
> On Thursday 28 April 2016 13:34:58 Pierre Chicoine wrote:
> > Dear Sirs
> >
> > First: Thank you for Qt3d. The KDAB people are heroes in my book.
> >
> > I have two problems in C++ Qt3D.
> >
> > 1. I am having a difficult time figuring out how to render 
QEntities into
> > separate QViewports. All my 3d objects draw to the first 
QViewport, the
> > rest are black. I have read all your articles and comments 
everywhere on

> > the Internet that I can find and I am basically confused.
> >
> > Is there a c++ example that would show multiple viewports with 
distinct
> > separate QEntities? I can't seem to duplicate The QML example 
multiviewport

> > in my code. What classes would get me there?
> >
> > 2. Also I'm also confused about QNodes and QEntitys and their
> > relationships. Maybe it's the use of Qt3d version 1 that is 
messing me up .
> > I use to have a scene node and all the entities would hang off of 
one scene
> > node for each scene. But that doesn't seem to work in version 2. 
Or do I

> > use the  addComponent on a QFrameGraph instead of a node? Or do I hang
> > Entities off of a viewport?
> >
> > Attached is a pic of my progress which draws all the objects into 
the same

> > viewport. The window tiles 2 windows properly but I only draw to one
> > viewport, the second or third stay black. The code here is what I 
repeat in
> > each scene class. It's a bit of a mess thrown together to test 
Qt3D classes
> > because I don't understand the relationships between all the Qt3D 
classes

> > used to place objects in a viewport.
> >
> >
> >  Qt3DCore::QCamera *cameraEntity = new Qt3DCore::QCamera( 
pParentNode);

> >
> > cameraEntity->setObjectName(QStringLiteral("cameraEntity"));
> >
> > 

Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[Pierre Chicoine]

Thank you Sean. Very descriptive.   Since I have such a large system, I
will create an example and pass it to you.

By the way a large percentage of your examples on 5.7 beta don't work. But
I'm sure you're aware of that.

Thank you again.

On Apr 30, 2016 10:55 AM, "Sean Harmer"  wrote:
>
> Hi,
>
> There's two things you need to consider:
>
> 1) The scene graph - the Entities that you wish to draw.
> 2) The framegraph - specifies the algorithm used to draw the scene graph
>
> I assume from your screenshot that you are more or less happy with
defining
> QEntity's to construct your scene graph. If you wish some entities to be
drawn
> in one part of the window (viewport) and the others in another viewport
then
> we need some way of saying "select this set of entities but not that set".
>
> One way of doing this is by using a QLayer component attached to your
entities
> that says which layer that entity is part of. This is just like layers
> photoshop, gimp, blender etc. Create a QLayer, give it a name, and
aggregate
> it onto your QEntity as you do the other components (mesh, transform and
> material).
>
> Doing this doesn't change anything in the rendering on it's own. To
affect the
> change we also need to modify the framegraph. To do this, make sure the
> concept of the framegraph is clear in your mind. Have a read of:
>
> https://www.kdab.com/qt3d-2-0-framegraph/
>
> Each leaf node, corresponds to a portion of your overall scene. To keep
things
> simple, lets only consider the viewports and layer filters you will need.
You
> will need other things in the framegraph too (rendersurfaceselector (if
using
> 5.7), camera selector, technique selector etc). The parts of the
framegraph
> concerned with viewports and layers will look something like this:
>
> Root (e.g. TechniqueSelector)
> |- Viewport [left half of window]
> |- LayerFilter [names="layer1"] (*)
> |- Viewport [right half of window]
> |- LayerFilter [names="layer2"] (**)
>
> Where:
>
> (*) <-- draws entities on "layer1" in left viewport
> (**) <-- draws entities on "layer2" in right viewport
>
> If you then want to use different cameras in the different viewports then
you
> can include a QCameraSelector node in each sub-tree.
>
> Root (e.g. TechniqueSelector)
> |- Viewport [left half of window]
> |- CameraSelector [camera1]
> |- LayerFilter [names="layer1"] (*)
> |- Viewport [right half of window]
> |- CameraSelector [camera2]
> |- LayerFilter [names="layer2"] (**)
>
> Where:
>
> (*) <-- draws entities on "layer1" in left viewport using "camera1"
> (**) <-- draws entities on "layer2" in right viewport using "camera2"
>
> Hopefully that makes sense. In the future, I hope we can provide tooling
and
> perhaps higher level ways of building custom framegraphs. The framegraph
is
> hugely powerful as it totally allows changing the rendering algorithm at
> runtime without having to touch low level C++ graphics code. However, it
is a
> bit tricky to get to grips with at first.
>
> Cheers,
>
> Sean
>
> On Thursday 28 April 2016 13:34:58 Pierre Chicoine wrote:
> > Dear Sirs
> >
> > First: Thank you for Qt3d. The KDAB people are heroes in my book.
> >
> > I have two problems in C++ Qt3D.
> >
> > 1. I am having a difficult time figuring out how to render QEntities
into
> > separate QViewports. All my 3d objects draw to the first QViewport, the
> > rest are black. I have read all your articles and comments everywhere on
> > the Internet that I can find and I am basically confused.
> >
> > Is there a c++ example that would show multiple viewports with distinct
> > separate QEntities? I can't seem to duplicate The QML example
multiviewport
> > in my code. What classes would get me there?
> >
> > 2. Also I'm also confused about QNodes and QEntitys and their
> > relationships. Maybe it's the use of Qt3d version 1 that is messing me
up .
> > I use to have a scene node and all the entities would hang off of one
scene
> > node for each scene. But that doesn't seem to work in version 2. Or do I
> > use the  addComponent on a QFrameGraph instead of a node? Or do I hang
> > Entities off of a viewport?
> >
> > Attached is a pic of my progress which draws all the objects into the
same
> > viewport. The window tiles 2 windows properly but I only draw to one
> > viewport, the second or third stay black. The code here is what I
repeat in
> > each scene class. It's a bit of a mess thrown together to test Qt3D
classes
> > because I don't understand the relationships between all the Qt3D
classes
> > used to place objects in a viewport.
> >
> >
> >  Qt3DCore::QCamera *cameraEntity = new Qt3DCore::QCamera( pParentNode);
> >
> >  cameraEntity->setObjectName(QStringLiteral("cameraEntity"));
> >
> >
cameraEntity->setProjectionType(Qt3DCore::QCameraLens::PerspectiveProjectio
> > n);
> >
> >  cameraEntity->setAspectRatio(1024 / 768);
> >
> >  cameraEntity->setUpVector(QVector3D(0.0f, 1.0f, 0.0f));
> >
> >  

Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[Sean Harmer]

On Thursday 28 April 2016 14:50:22 charleyb123 . wrote:
> Pierre spaketh:
> > Dear Sirs
> > 
> > First: Thank you for Qt3d. The KDAB people are heroes in my book.
> > 
> 
> +1
> 
> A very big "Thank You!" to what KDAB does in Qt3D.
> 
> They probably don't hear it often enough for all their
> work-and-contributions, but Qt3D is truly technology that pushes the entire
> industry.

Thanks Charley! That's very nice to hear (especially when battling an 
uncooperative CI on a Bank Holiday weekend)!

Sean
--
Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK
Klarälvdalens Datakonsult AB, a KDAB Group company
Tel. UK +44 (0)1625 809908, Sweden (HQ) +46-563-540090
KDAB - Qt Experts - Platform-independent software solutions
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Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[Sean Harmer]

Hi,

There's two things you need to consider:

1) The scene graph - the Entities that you wish to draw.
2) The framegraph - specifies the algorithm used to draw the scene graph

I assume from your screenshot that you are more or less happy with defining 
QEntity's to construct your scene graph. If you wish some entities to be drawn 
in one part of the window (viewport) and the others in another viewport then 
we need some way of saying "select this set of entities but not that set".

One way of doing this is by using a QLayer component attached to your entities 
that says which layer that entity is part of. This is just like layers 
photoshop, gimp, blender etc. Create a QLayer, give it a name, and aggregate 
it onto your QEntity as you do the other components (mesh, transform and 
material).

Doing this doesn't change anything in the rendering on it's own. To affect the 
change we also need to modify the framegraph. To do this, make sure the 
concept of the framegraph is clear in your mind. Have a read of:

https://www.kdab.com/qt3d-2-0-framegraph/

Each leaf node, corresponds to a portion of your overall scene. To keep things 
simple, lets only consider the viewports and layer filters you will need. You 
will need other things in the framegraph too (rendersurfaceselector (if using 
5.7), camera selector, technique selector etc). The parts of the framegraph 
concerned with viewports and layers will look something like this:

Root (e.g. TechniqueSelector)
|- Viewport [left half of window]
|- LayerFilter [names="layer1"] (*)
|- Viewport [right half of window]
|- LayerFilter [names="layer2"] (**)

Where:

(*) <-- draws entities on "layer1" in left viewport
(**) <-- draws entities on "layer2" in right viewport

If you then want to use different cameras in the different viewports then you 
can include a QCameraSelector node in each sub-tree.

Root (e.g. TechniqueSelector)
|- Viewport [left half of window]
|- CameraSelector [camera1]
|- LayerFilter [names="layer1"] (*)
|- Viewport [right half of window]
|- CameraSelector [camera2]
|- LayerFilter [names="layer2"] (**)

Where:

(*) <-- draws entities on "layer1" in left viewport using "camera1"
(**) <-- draws entities on "layer2" in right viewport using "camera2"

Hopefully that makes sense. In the future, I hope we can provide tooling and 
perhaps higher level ways of building custom framegraphs. The framegraph is 
hugely powerful as it totally allows changing the rendering algorithm at 
runtime without having to touch low level C++ graphics code. However, it is a 
bit tricky to get to grips with at first.

Cheers,

Sean

On Thursday 28 April 2016 13:34:58 Pierre Chicoine wrote:
> Dear Sirs
> 
> First: Thank you for Qt3d. The KDAB people are heroes in my book.
> 
> I have two problems in C++ Qt3D.
> 
> 1. I am having a difficult time figuring out how to render QEntities into
> separate QViewports. All my 3d objects draw to the first QViewport, the
> rest are black. I have read all your articles and comments everywhere on
> the Internet that I can find and I am basically confused.
> 
> Is there a c++ example that would show multiple viewports with distinct
> separate QEntities? I can't seem to duplicate The QML example multiviewport
> in my code. What classes would get me there?
> 
> 2. Also I'm also confused about QNodes and QEntitys and their
> relationships. Maybe it's the use of Qt3d version 1 that is messing me up .
> I use to have a scene node and all the entities would hang off of one scene
> node for each scene. But that doesn't seem to work in version 2. Or do I
> use the  addComponent on a QFrameGraph instead of a node? Or do I hang
> Entities off of a viewport?
> 
> Attached is a pic of my progress which draws all the objects into the same
> viewport. The window tiles 2 windows properly but I only draw to one
> viewport, the second or third stay black. The code here is what I repeat in
> each scene class. It's a bit of a mess thrown together to test Qt3D classes
> because I don't understand the relationships between all the Qt3D classes
> used to place objects in a viewport.
> 
> 
>  Qt3DCore::QCamera *cameraEntity = new Qt3DCore::QCamera( pParentNode);
> 
>  cameraEntity->setObjectName(QStringLiteral("cameraEntity"));
> 
>  cameraEntity->setProjectionType(Qt3DCore::QCameraLens::PerspectiveProjectio
> n);
> 
>  cameraEntity->setAspectRatio(1024 / 768);
> 
>  cameraEntity->setUpVector(QVector3D(0.0f, 1.0f, 0.0f));
> 
>  cameraEntity->setViewCenter(QVector3D(0.0f, 3.5f, 0.0f));
> 
>  //cameraEntity->lens()->setPerspectiveProjection(60.0f, 16.0f/9.0f,
> 0.1f, 1000.0f);
> 
> 
>  if(pScenesSet) // if it's a scene then we want to set it where they want it
> 
>   cameraEntity->setPosition(QVector3D(pScenesSet->CamXPos - 20,
> pScenesSet->CamYPos + 80, pScenesSet->CamZPos));
> 
>  else // so it's a schematic
> 
>   cameraEntity->setPosition(QVector3D(-20, 65, 180));
> 
> 
>  theApp->input->setCamera(cameraEntity); // not sure 

Re: [Interest] [QT3D] How Do I render multiple QEntities in different QViewports in C++?

[charleyb123 .]

Pierre spaketh:

> Dear Sirs
>
> First: Thank you for Qt3d. The KDAB people are heroes in my book.
> 
>

+1

A very big "Thank You!" to what KDAB does in Qt3D.

They probably don't hear it often enough for all their
work-and-contributions, but Qt3D is truly technology that pushes the entire
industry.

--charley
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