How to manually make a dynamic body (ball) to go to the window in box2d iPhone

Question

As I am new to cocos2d, and I try my best. Someone will suggest me how to work on this.

• I have 3 boxes (which are kinematic bodies)

• There are also several balls (which are dynamic bodies) that have a tag value (window number) for each ball.

• I have some obstacles (kinematic bodies) between where the ball shoots and the boxes.

In the script, I get a random window number: 2 (second field) and is set as the tag value for the ball. And the ball must go into the second box for sure, even if it hits obstacles. And if I got the box number for the next ball, like 3, the ball should go to the third box.

Can anyone suggest me

Thanks Monish

Answer 1

Here is a simple helper class for creating balls and returning. You can use a similar approach to create fields.

// // Ball.h // BouncingBall // // Created by Omar Hussain on 8/12/10. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import <Foundation/Foundation.h> #import "cocos2d.h" #import "Box2D.h" class Ball : public CCSprite { public: CCSprite *sprite; b2BodyDef ballBodyDef; b2Body *ballBody; b2FixtureDef ballShapeDef; b2Fixture *fixture; Ball(b2World *world); b2Vec2 disp; CCSprite *shadowBall; b2World *world; bool isAnimating; void SetBallOverlap(bool willOverlap, int scale); void Destroy(); }; #import "Ball.h" #define Density 1.0f #define Friction 1.0f #define Restitution 0.8f #define PTM_RATIO 32 #define SpriteRadius 40.5 Ball::Ball(b2World *world){ this->world = world; this->sprite = [CCSprite spriteWithFile:@"5.png"]; [sprite setPosition:ccp(160,460)]; this->isAnimating = false; //Set up sprite ballBodyDef.type = b2_dynamicBody; ballBodyDef.position.Set(160/PTM_RATIO, 460/PTM_RATIO); ballBodyDef.userData = sprite; this->ballBody = world->CreateBody(&ballBodyDef); b2CircleShape circle; circle.m_radius = SpriteRadius/PTM_RATIO; ballShapeDef.shape = &circle; ballShapeDef.density = Density; ballShapeDef.friction =Friction; ballShapeDef.restitution = Restitution; this->fixture = this->ballBody->CreateFixture(&ballShapeDef); //this->shadowBall = [TSprite spriteWithFile:@"ball_shadow.png"]; } void Ball::SetBallSize(int scale){ this->ballBody->DestroyFixture(fixture); this->world->DestroyBody(ballBody); ballBodyDef.type = b2_dynamicBody; ballBodyDef.position.Set(160/PTM_RATIO, 460/PTM_RATIO); ballBodyDef.userData = sprite; this->ballBody = world->CreateBody(&ballBodyDef); float correctedScale = scale/9.0; b2CircleShape circle; circle.m_radius = (correctedScale *SpriteRadius)/PTM_RATIO; ballShapeDef.shape = &circle; ballShapeDef.density = Density; ballShapeDef.friction = Friction; ballShapeDef.restitution = Restitution; this->fixture = this->ballBody->CreateFixture(&ballShapeDef); //this->shadowBall.scale = scale; this->sprite.scale = correctedScale; } void Ball::SetBallOverlap(bool willOverlap, int scale){ this->world->DestroyBody(ballBody); ballBodyDef.type = b2_dynamicBody; ballBodyDef.position.Set(160/PTM_RATIO, 460/PTM_RATIO); ballBodyDef.userData = sprite; this->ballBody = world->CreateBody(&ballBodyDef); float correctedScale = scale/9.0; b2CircleShape circle; circle.m_radius = (correctedScale *SpriteRadius)/PTM_RATIO; ballShapeDef.shape = &circle; ballShapeDef.density = Density; ballShapeDef.friction = Friction; ballShapeDef.restitution = Restitution; if(willOverlap) ballShapeDef.filter.groupIndex = 1; else ballShapeDef.filter.groupIndex = -1; this->ballBody->CreateFixture(&ballShapeDef); } void Ball::Destroy(){ this->ballBody->DestroyFixture(fixture); this->world->DestroyBody(ballBody); }