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Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 9:14 am
by jpablo2003
I want to do an example abaut draggin objects and explosions, but I don't know how to do it.

I put you an example I want to do it.
http://www.emanueleferonato.com/2008/11 ... x2d-flash/
Under the source code there is an example of dragging a boxes.

Can anyone say to me how to do it?

Thank you.

Re: Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 10:52 am
by slembcke
Yes. The Chipmunk demo application implements mouse dragging in a very similar fashion. It's even a bit simpler in Chipmunk because it has a point query feature.

Code: Select all

static void
click(int button, int state, int x, int y)
{
        if(button == GLUT_LEFT_BUTTON){
                if(state == GLUT_DOWN){
                        cpVect point = mouseToSpace(x, y);
                
                        cpShape *shape = cpSpacePointQueryFirst(space, point, GRABABLE_MASK_BIT, CP_NO_GROUP);
                        if(shape){
                                cpBody *body = shape->body;
                                mouseJoint = cpPivotJointNew2(mouseBody, body, cpvzero, cpBodyWorld2Local(body, point));
                                mouseJoint->maxForce = 50000.0f;
                                mouseJoint->biasCoef = 0.15f;
                                cpSpaceAddConstraint(space, mouseJoint);
                        }
                } else if(mouseJoint){
                        cpSpaceRemoveConstraint(space, mouseJoint);
                        cpConstraintFree(mouseJoint);
                        mouseJoint = NULL;
                }
        }
}
I smooth out the mouse position and update it like this once every frame.

Code: Select all

        cpVect newPoint = cpvlerp(mousePoint_last, mousePoint, 0.25f);
        mouseBody->p = newPoint;
        mouseBody->v = cpvmult(cpvsub(newPoint, mousePoint_last), 60.0f);
        mousePoint_last = newPoint;
You can see all of the code here: http://code.google.com/p/chipmunk-physi ... munkDemo.c

Re: Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 10:57 am
by jpablo2003
Thank you, bay I want it the example for XCode.

Re: Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 10:59 am
by jpablo2003
would you can put to me two examples very simple, please.

Re: Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 11:05 am
by slembcke
That file, ChipmunkDemo.c, is included with Chipmunk and there is an XCode project.

Re: Example dragging object and explosions for XCode

Posted: Tue May 31, 2011 11:20 am
by jpablo2003
Thank you but where find it?

I'm a bit lost.

Re: Example dragging object and explosions for XCode

Posted: Wed Jun 01, 2011 1:45 am
by jpablo2003
Good morning, can anydody help me, please?

Thank you

Re: Example dragging object and explosions for XCode

Posted: Wed Jun 01, 2011 8:37 am
by jpablo2003
I see that nobody wants to help me, please, I need know how do it for XCode.

Greetings

Re: Example dragging object and explosions for XCode

Posted: Wed Jun 01, 2011 9:35 am
by slembcke
If you download the latest Chipmunk from the Google Code page, the XCode project is in that.
http://code.google.com/p/chipmunk-physics/

Unless you downloaded Chipmunk from somewhere else, or it was packaged with something else, you already have the XCode project.

Re: Example dragging object and explosions for XCode

Posted: Wed Jun 01, 2011 10:16 am
by jpablo2003
I don't understand, how I do an example apart, only I need that.

Thank you