topic Draw on viewport. in ObjectARX Forum

Draw on viewport.

Anonymous — Wed, 25 Jul 2012 07:00:06 GMT

I want to draw some graphics on viewport.

On rotating the co-ordinate system this graphics must not transform.

how to do it.

Re: Draw on viewport.

maisoui — Wed, 25 Jul 2012 09:14:05 GMT

Hi,

I'm not sure I understood your wish, but I've a solution to draw a custom entity always in front of camera's eye regardless of the view or the coordinate system. Maybe it will give you some ideas.

First:

Adesk::Boolean CustomEntity::subWorldDraw(AcGiWorldDraw * wd) 
{
	assertReadEnabled();
	return Adesk::kFalse; // -> call viewport draw
}

Then:

void CustomEntity::subViewportDraw(AcGiViewportDraw * mode)
{
	assertReadEnabled();

	//independant of the viewport's camera and target locations
	AcGiViewport * pViewport = &mode->viewport();

	AcGeVector3d normal = pViewport->viewDir();
	AcGeVector3d vY;
	pViewport->getCameraUpVector(vY);
	vY.normalize();
	AcGeVector3d vX = vY.crossProduct(normal);
	vX.normalize();

	mode->geometry().circle(m_ptWcs, 50., normal);
}

Example above will draw a circle always in front of user. You can try to rotate view cube.

Regards,

Jonathan

Re: Draw on viewport.

Anonymous — Wed, 25 Jul 2012 11:29:19 GMT

Thanks for the reply.

It was really useful.

But still have some issues.

When I pan or zoom, the circle gets translated/pan.

Why this is so?

Any solution for this.?

Waiting for reply.

Re: Draw on viewport.

maisoui — Wed, 25 Jul 2012 11:39:28 GMT

I guess you need to calculate the position where you draw the circle in the worlddraw method.

With AcGsView you can retrieve the screen's center point, like this:

AcGsView * pView = NULL;
int vportNum = 0;
if(!getGsViewObj(pView, vportNum))
    return false;

ptCenterWcs = pView->target();

My suggestion is to draw your circle at a position relative to the view's target (= center of screen).

Regards,

Jonathan

Re: Draw on viewport.

Anonymous — Wed, 25 Jul 2012 12:35:42 GMT

==Got Error==

identifier "getGsViewObj" is undefined.

Re: Draw on viewport.

maisoui — Wed, 25 Jul 2012 12:37:48 GMT

And AcGiViewport::getCameraTarget (according to my first sample)?

Re: Draw on viewport.

Anonymous — Wed, 25 Jul 2012 12:42:56 GMT

Sorry.. but it doesn't work.

Same output.

It works exactly correct for rotation. But on pan it moves. Same for zoom in and zoom out.

Re: Draw on viewport.

fenton_webb — Mon, 30 Jul 2012 22:57:00 GMT

First of all, try not to use AcGsView inside of your viewportDraw - besides the fact that it depends on acad.exe which will stop your object enabler working inside of other RealDWG hosts it can be very expensive on performance.

If you want to draw scale dependent graphics inside of your viewportDraw, you can use AcGiViewport::getNumPixelsInUnitSquare to determine your geometry size

Re: Draw on viewport.

Anonymous — Thu, 09 Aug 2012 09:17:46 GMT

Thanks for the reply Fenton.

Can you please help me with the code.

Waiting for reply.

Re: Draw on viewport.

Anonymous — Thu, 09 Aug 2012 09:19:20 GMT

Still I cant find the solution.

Please help ASAP.

Re: Draw on viewport.

owenwengerd — Thu, 09 Aug 2012 14:23:34 GMT

You'll be more likely to get assistance if you post your code and explain where it fails.

Re: Draw on viewport.

Anonymous — Fri, 10 Aug 2012 06:29:47 GMT

The code posted above works for rotation.... but fail for pan and zoom..

When i rotate, it repaint..... but when i pan/zoom it dont do repaint...

Re: Draw on viewport.

fenton_webb — Mon, 13 Aug 2012 18:55:54 GMT

We have a function called AcGiDrawable::SetAttributes() - you should override that in your Custom entity and then check out the SetAttributesFlags enumeration...I bet if you return kDrawableViewDependentViewportDraw it will start working...

enum SetAttributesFlags {
kDrawableNone = 0,
kDrawableIsAnEntity = 1,
kDrawableUsesNesting = 2,
kDrawableIsCompoundObject = 4,
kDrawableViewIndependentViewportDraw = 8,
kDrawableIsInvisible = 16,
kDrawableHasAttributes = 32,
kDrawableRegenTypeDependantGeometry = 64,
kDrawableIsDimension = (kDrawableIsAnEntity + kDrawableIsCompoundObject + 128),
kDrawableRegenDraw = 256,
kDrawableStandardDisplaySingleLOD = 512,
kDrawableShadedDisplaySingleLOD = 1024,
kDrawableViewDependentViewportDraw = 2048,
kDrawableBlockDependentViewportDraw = 4096,
kDrawableIsExternalReference = 8192,
kDrawableNotPlottable = 16384
};

Re: Draw on viewport.

fenton_webb — Mon, 13 Aug 2012 22:17:33 GMT

Did you read this? http://adndevblog.typepad.com/autocad/2012/06/how-to-control-an-entity-viewportdraw-so-that-it-always-displays-a-plan-view-using-objectarx.html

Re: Draw on viewport.

Anonymous — Thu, 07 Mar 2013 14:25:45 GMT

Hi,

I was facing the same issue, returning kDrawableViewDependentViewportDraw fixed it in 3d mode only but in 2dwireframe, subSetAttributes/subWorldDraw/subViewportDraw are not called on my drawable during (or event after) zoom/pan.

Is there any way to work around this?

Thanks

Loic Jourdan