object/poly behind mouse cursor

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On 06/07/2008 at 11:23, xxxxxxxx wrote:

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---------
Hi,

i want to get info about the polygon 'behind' the mouse cursor, that is its position and normal direction.

i realize there's the viewportSelect::getPolyInfo() and so on, but i cant quite get it to work :(

it seems i have to init the viewportselect with an object, but im not sure which object to use, bc as i see it, all objects of the scene may potentially be behind the mouse cursor.. sp why do i have to choose one and init the viewportselect with it ?

anybody has some experience with this ?

thanks,
cineast

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On 06/07/2008 at 11:37, xxxxxxxx wrote:

im gettings the feeling im on the wrong track using viewportselect.

maybe its better to use geRayCollider and shoot a ray from the mouse cursor screen pos into viewport space.
the rayCollider::Intersect needs an object as argument too though, to check if it collides with the ray..

so do i have to loop through all objects in my scece to figure out which one is behind the mouse cursor ?

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On 07/07/2008 at 01:58, xxxxxxxx wrote:

ok nevermind, meanwhile i found the solution in another post here..

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On 14/07/2008 at 02:48, xxxxxxxx wrote:

It would be maybe interesting for the other forum members to know how you solved the problem. Maybe you can share what you have found out.

cheers,
Matthias

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On 14/07/2008 at 03:01, xxxxxxxx wrote:

of course, forgot about tat sry ;-)

im using GeRayCollider to shoot rays from my eye through the mouse cursor, just like superman would do ;-)

in the code below im checking if the ray hits the currently active object:

> \> AutoAlloc<GeRayCollider> rc;      \> if (!rc) return FALSE; \> // the object i want to know if it was hit \> BaseObject\* obj = doc->GetActiveObject(); \> \> Vector wtail = bd->SW(Vector(mx,my,0)); \> Vector whead = bd->SW(Vector(mx,my,10000.0)); \> Vector otail = (!obj->GetMg()) \* wtail; \> Vector oray = (whead - wtail) ^ (!obj->GetMg()); \> \> // init rayCollider with object to check ray collisions on           \> rc->Init(obj,TRUE); \> // check for intersection, 10000 is the length of the ray \> rc->Intersect(otail, !oray, 10000.0);                                               \> \> // if a ray has hit the object \> if(rc->GetNearestIntersection(&res;)){ \> . \> . \> // res.hitpos has the hit position \> // and res.f_normal is the normal vec of the hit polygon \> . \> . \> } \>

the stuff with the computation on the right vector, i found using the forum search here.

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On 14/07/2008 at 03:03, xxxxxxxx wrote:

Thanks for sharing

cheers,
Matthias

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On 02/04/2011 at 05:25, xxxxxxxx wrote:

Hi,

I am trying this exact thing and am not getting any results.

Here's the code I am using.

  
  
  BaseObject* pObj = doc->GetActiveObject();  
  if(!pObj) return FALSE;  
  
  AutoAlloc<GeRayCollider> cRay;  
  if (!cRay) return FALSE;  
  
  GeRayColResult res;  
  
  // Make sure RayCollider is there  
  if (!cRay)  
  {  
      GePrint("ERROR - RayCollider not Initialized");  
      return FALSE;  
  }  
  
  Vector wtail =    bd->SW(Vector(x, y, UM_START));  
  Vector whead =    bd->SW(Vector(x, y, UM_END)) - wtail;  
  Vector otail = (!pObj->GetMg()) * wtail;  
  Vector oray     = (whead - wtail) ^ (!pObj->GetMg());  
  
  
  cRay->Init(pObj, TRUE);  
  cRay->Intersect(otail, !oray, 10000.0);  
  
  
  if (cRay->GetNearestIntersection(&res))  
  {  
      GePrint("A COLLISION HAS OCCURED");  
      return TRUE;  
  }  
  
  return TRUE;  
  

I am not seeing anything in the console that says "A COLLISION HAS OCCURED"  when I put my mouse over the active object...    Does anyone see a reason why my code wouldn't work?

Thanks,

Shawn

EDIT:  DOH!  I figured it out.  My collider was too short.  :)  Remember size does matter.  ;)

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On 02/04/2011 at 11:44, xxxxxxxx wrote:

Is there a more complete example of this?

I'm assuming that bd is a parameter used with this class method:
virtual DRAWRESULT Draw  (BaseObject *op, DRAWPASS type, BaseDraw *bd, BaseDrawHelp *bh);

So I'm also assuming that the DRAWRESULT method needs to also be used.
But what goes inside of it?

Can anyone provide a more complete example of this?

-ScottA

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On 02/04/2011 at 11:51, xxxxxxxx wrote:

what specifically would you like to achieve with it?  I could be more specific if I knew what you were looking to do.  :)

To answer your first question,  bd is the BaseDraw that is allocated in my function.  In my case I am calling my function from the Draw() function which also allocates a BaseBraw so I just use the bd from that function and pass it to my own.

If you'd like I can repost the code I posted above with more comments to explain what each thing does.  :)

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On 02/04/2011 at 12:21, xxxxxxxx wrote:

Hi Shawn,
I'm just trying to learn how to do basic ray collision that prints a message to the console when the mouse is over an object.

I think I understand the code that's been posted so far. But it's only a small portion of the entire .cpp file. And I'm having trouble building the stuff that's not been listed to make it work.
Namely the classes and the methods.

-ScottA

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On 02/04/2011 at 12:32, xxxxxxxx wrote:

The code above is coming from a ToolData plugin.   You could put the following code in the Draw() function of a tooldata plugin,

  
  
TOOLDRAW MyClass::Draw(BaseDocument* doc, BaseContainer& data, BaseDraw* bd, BaseDrawHelp* bh, BaseThread* bt, TOOLDRAWFLAGS flags){  
    
    
    BaseObject* pObj = doc->GetActiveObject();  
      if(!pObj) return TOOLDRAW_0;  
      
      AutoAlloc<GeRayCollider> cRay;  
      if (!cRay) return TOOLDRAW_0;  
      
      GeRayColResult res;  
      
      // Make sure RayCollider is there  
      if (!cRay)  
      {  
          GePrint("ERROR - RayCollider not Initialized");  
          return TOOLDRAW_0;  
      }  
      
      Vector wtail =    bd->SW(Vector(mouseX, mouseY, 0));  
      Vector whead =    bd->SW(Vector(mouseX, mouseY, 100000));  
      Vector otail = (!pObj->GetMg()) * wtail;  
      Vector oray     = (whead - wtail) ^ (!pObj->GetMg());  
      
      
      cRay->Init(pObj, TRUE);  
      cRay->Intersect(otail, !oray, 10000.0);  
      
      
      if (cRay->GetNearestIntersection(&res))  
      {  
          GePrint("A COLLISION HAS OCCURED");  
      }  
      
      return TOOLDRAW_0;  
      
    }  
    

mouseX and mouseY are global Reals.  Both declared as global variables.   Then in the GetCursorInfo()  you would simply put   

  
      
    Bool MyClass::GetCursorInfo(BaseDocument* doc, BaseContainer& data, BaseDraw* bd, Real x, Real y, BaseContainer& bc){  
      
    mouseX = x;  
    mouseY = y;  
    if (x > -1.0f)     SpecialEventAdd(EVMSG_UPDATEHIGHLIGHT);  
      
    return TRUE;  
      
    }  
    

This should give you a working model to learn from.   :)  
  
  
Hope that helps.  
  
~Shawn  

_<_h4_>__<_h4_>_/h4>

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On 02/04/2011 at 13:06, xxxxxxxx wrote:

Thanks Shawn.
Got it working now.:thumbsup:

BTW: Did you ever figure out how to merge documents?

-ScottA

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On 02/04/2011 at 13:11, xxxxxxxx wrote:

I did.   I don't have the code here though because i am not home..  send me a PM at c4d cafe to remind me and i will send it to you when i get home.  I keep forgetting to send it to you cuz when i get outa work i get focused on other things  lol

sorry about that.  :)

~Shawn

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On 02/04/2011 at 14:07, xxxxxxxx wrote:

I'm not a member there.

My e-mail is:  [email protected]

Thanks,
-ScottA