[Solved] Custom Rendering

[skyforger]

Hello,

I've followed the tutorial here http://www.cegui.org.uk/wiki/index.php/ ... right_time on custom rendering. I'm using the Ogre renderer so I've created an OgreGeometryBuffer like so:

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mDragSeparatorGB = (OgreGeometryBuffer*)(&System::getSingletonPtr()->getRenderer()->createGeometryBuffer());

And then drawn a rectangle in it with the generic brush:

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Image brush = ImagesetManager::getSingleton().get( "BlenderTheme" ).getImage( "ClientBrush" );
brush.draw( *mDragSeparatorGB, Vector2( 0, 0 ), Size( 100, 100 ), new Rect(0, 0, 100, 100),  0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF );

After that, I added the geometry buffer to the surface and called the superclass drawSelf() method:

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surface->addGeometryBuffer( ctx.queue, *mDragSeparatorGB );
MultiColumnList::drawSelf( ctx );

Unfortunately, I can't get anything rendered. Does anyone have any ideas what I'm doing wrong?

Thanks

[CrazyEddie]

It is possible (likely?) that the default implementation rendering is overdrawing the custom content. Does anything change if you add the buffer containing the custom content after calling the superclass?

Also, you're probably aware, but the "new Rect" in the Image::draw call is a horrible memory leak

CE.

[skyforger]

Thanks for the response. I did have a few leaks from the hastily written code and I was aware of most of them. They got cleared as soon as the approach didn't work, but it seems this one slipped. Here's what I've tried ( and didn't work ):

• Adding the geometry buffer after calling the superclass ( like you suggested ).
• Removing the super class call all together but nothing happened ( except for the window not being drawn, that is ).
• Using the brush from another widget and using a different brush from the imageset to make sure the image wasn't the problem.
• I've checked the buffer's vertex array. It holds the 6 vertices added by the brush forming the right quad as expected.
• Setting the clipping region with mDragSeparatorGB->setClippingRegion( Rect( 0, 0, 100, 100 ) );
• Adding the geometry buffer to another render queue ( overlay ) with surface->addGeometryBuffer( RQ_OVERLAY, *mDragSeparatorGB );

Any ideas what else I could try?

[skyforger]

I've managed to catch a glimpse of the rectangle. It's being draw for just one frame, and then it disappears. Also, not every draw call of the window causes the rectangle to briefly appear. I'm not sure what could be causing this.

[skyforger]

I've solved it! Looking at the CEGUI::Window implementation I found this:

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void Window::queueGeometry(const RenderingContext& ctx)
{
    // add geometry so that it gets drawn to the target surface.
    ctx.surface->addGeometryBuffer(ctx.queue, *d_geometry);
}

However, the tutorial code for this was:

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if (ctx.surface->isRenderingWindow())
    surface = &static_cast<RenderingWindow*>(ctx.surface)->getOwner();
else
    surface = ctx.surface;


Adding the geometry buffer to the context surface and not the owner did the trick.

[CrazyEddie]

Ah, right... cool

I should likely add / reiterate why the tutorial has that...

Basically what is developed in that tutorial performs rendering of lines/arrows that emanate from the edge of one FrameWindow and point towards the edge of another. In order that this rendering be successful when the FrameWindow objects have their own rendering surface, we must render to the parent surface - otherwise the custom rendering is clipped to the edges of the child surface and nothing would show up (or to put it another way, the tutorial code needs to render outside of the window's surface area, so draws on the parent surface).

CE.

[skyforger]

Yes, I understand what the tutorial was supposed to do, I read the forum post about the node editor ( rendering the linking lines between the windows ) so It would make sense to draw on the parent surface. Initially, I was drawing outside the window as well, but that brief flicker was happening.

Thanks for the feedback.