KoboldTouch physics collision demo code http://www.koboldtouch.com

gistfile1.m

//
//  PhysicsCollisionSceneViewController.m
//  _Feature-Demo-Template_
//
//  Created by Steffen Itterheim on 01.05.13.
//  Copyright 2013 __MyCompanyName__. All rights reserved.
//

#import "PhysicsCollisionSceneViewController.h"


@implementation PhysicsCollisionSceneViewController

-(void) createTest
{
  KTPhysicsController* physicsController = [KTPhysicsController physicsControllerWithBox2D];
	physicsController.gravity = CGPointMake(0, -10);
	[physicsController constrainWorldToWindow];
	[self addSubController:physicsController];

	[self createBouncingIcon];
	[self createSensorBody];
	[self createFilteredBody];

	KTPhysicsDebugViewController* debugVC = [KTPhysicsDebugViewController physicsDebugViewControllerWithPhysicsController:physicsController];
	[self addSubController:debugVC];
}

-(void) createBouncingIcon
{
	KTPhysicsBodyModel* bodyModel = [KTPhysicsBodyModel physicsBodyModelWithPhysicsController:self.sceneViewController.physicsController];

	KTPhysicsBody* body = bodyModel.physicsBody;
	body.contactDelegate = self;
	body.position = CGPointMake(150, 40);
	body.linearVelocity = CGPointMake(0, 5);

	KTPhysicsShape* shape = [KTPhysicsCircleShape circleShapeWithRadius:22];
	KTPhysicsFixture* fixture = [body createFixtureWithShape:shape];
	fixture.restitution = 1.1f;

	[fixture setContactCategory:@"icon"];
	[fixture disableCollisionWithCategory:@"noIconContact"];

	_iconSprite = [CCSprite spriteWithFile:@"Icon.png"];

	KTViewController* vc = [KTViewController controller];
	vc.rootNode = _iconSprite;
	vc.model = bodyModel;
	[self addSubController:vc];
}

#pragma mark Contact Callbacks (in the order they are being called)

-(void) beginContact:(KTPhysicsContact*)contact body:(KTPhysicsBody*)body otherBody:(KTPhysicsBody*)otherBody
{
	//NSLog(@"beginContact");
	_iconSprite.color = ccRED;

	if (body.model.position.y > 250)
	{
		body.linearVelocity = CGPointZero;
		body.angularVelocity = CCRANDOM_MINUS1_1() * 20.0f;

		// get the body's only fixture
		KTPhysicsFixture* fixture = [body.fixtures anyObject];
		[fixture enableCollisionWithCategory:@"noIconContact"];

		// only do this once because TTF string updates are sloooooow
		if (_didChangeFilterString == NO)
		{
			_didChangeFilterString = YES;
			[_filterLabel setString:@"Now I can Contact Icon!"];
		}
	}
}

-(void) preSolveContact:(KTPhysicsContact*)contact body:(KTPhysicsBody*)body otherBody:(KTPhysicsBody*)otherBody oldManifold:(KTPhysicsManifold*)oldManifold
{
	//NSLog(@"preSolveContact");

	// to ignore a specific contact until the next update you would do this:
	//contact.enabled = NO;
}

-(void) postSolveContact:(KTPhysicsContact*)contact body:(KTPhysicsBody*)body otherBody:(KTPhysicsBody*)otherBody impulse:(KTPhysicsContactImpulse*)impulse
{
	//NSLog(@"postSolveContact");
}

-(void) endContact:(KTPhysicsContact*)contact body:(KTPhysicsBody*)body otherBody:(KTPhysicsBody*)otherBody
{
	//NSLog(@"endContact");
	_iconSprite.color = ccWHITE;
}

#pragma mark other colliding bodies

-(void) createSensorBody
{
	KTPhysicsBodyModel* bodyModel = [KTPhysicsBodyModel physicsBodyModelWithPhysicsController:self.physicsController];

	KTPhysicsBody* body = bodyModel.physicsBody;
	body.position = CGPointMake(230, 170);
	body.gravityScale = 0; // unaffected by gravity
	body.allowSleeping = NO;

	CCLabelTTF* label = [CCLabelTTF labelWithString:@"I'm a sensor body" fontName:@"GurmukhiMN-Bold" fontSize:40];

	KTPhysicsShape* shape = [KTPhysicsRectShape rectShapeWithSize:label.contentSize];
	KTPhysicsFixture* fixture = [body createFixtureWithShape:shape];
	fixture.isSensor = YES;
	[fixture setContactCategory:@"sensor"];

	// this is where it all comes together
	KTViewController* vc = [KTViewController controller];
	vc.rootNode = label;
	vc.model = bodyModel;
	[self addSubController:vc];
}

-(void) createFilteredBody
{
	KTPhysicsBodyModel* bodyModel = [KTPhysicsBodyModel physicsBodyModelWithPhysicsController:self.physicsController];

	KTPhysicsBody* body = bodyModel.physicsBody;
	body.position = CGPointMake(200, 60);
	body.gravityScale = 0; // unaffected by gravity
	body.allowSleeping = NO;

	_filterLabel = [CCLabelTTF labelWithString:@"My contacts are filtered out" fontName:@"GurmukhiMN" fontSize:20];

	KTPhysicsShape* shape = [KTPhysicsRectShape rectShapeWithSize:_filterLabel.contentSize];
	KTPhysicsFixture* fixture = [body createFixtureWithShape:shape];
	fixture.isSensor = YES;
	[fixture setContactCategory:@"noIconContact"];

	// this is where it all comes together
	KTViewController* vc = [KTViewController controller];
	vc.rootNode = _filterLabel;
	vc.model = bodyModel;
	[self addSubController:vc];
}

@end