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I have b2Body of which i set angle using setTransform. But I want b2Body to move in particular angle. My CCSprite is moving in that angle using ccMoveBy. But my b2Body is not moving with that CCSprite. So I thought of using setTransform. I set the angle with the same value by which I'm moving CCSprite. But still b2Body moves somewhere else.

I have used it like

b->setTransform(b->getPosition(),30*DEG_TO_RED);
b->setLinearVelocity(b2Vec2(120,180));

Any help is grealy appreciated.

Thank you,.

Martijn Courteaux
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2 Answers2

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If you want to move b2Body by yourself then it is a good idea to make it a kinematic body (you can change body's type every time you want). Then just set the velocity:

body->SetType(b2_kinematikBody);
float angle = 30*M_PI/180.0f;
float spd = 50;
b2Vec2 velocity = spd*b2Vec2(cos(angle), sin(angle));
body->SetLinearVelocity(velocity);
Andrew
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#define CC_DEGREES_TO_RADIANS(__ANGLE__) ((__ANGLE__) * 0.01745329252f) // PI / 180

this is for 30degree rotation of body and not change in its position.

    b->setTransform(b->getPosition(),CC_DEGREES_TO_RADIANS(30));

    b->setLinearVelocity(b2Vec2(120,180));

or

    b->setTransform(b2Vec(100/PTMRATIO,200/PTMRATIO),CC_DEGREES_TO_RADIANS(30));

here i changed to 100 X 200Y POSITION

import "CGPointExtension.h"

        b->setTransform(ccpAdd(b2Vec(100/PTMRATIO,200/PTMRATIO), b2Vec(50/PTMRATIO,50/PTMRATIO)),CC_DEGREES_TO_RADIANS(30));
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Vijay-Apple-Dev.blogspot.com
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  • so how to change the position in particular angle?? – Anks Jul 06 '11 at 12:48
  • I want it to move in particular angle? I can change the position but now say i want b2Body to move by 5 then it should move by 5 to that particular angle like CCSprite. – Anks Jul 06 '11 at 13:45
  • You can use body->GetAngle() to get the current angle, then just add to that. This tutorial might help: http://www.iforce2d.net/b2dtut/rotate-to-angle – iforce2d Jul 07 '11 at 07:32