objective-c iPhone game programming : detect touch on tile map object layer - iphone

Question

hi made an object layer on my tile map with tile map editor like this :
http://i.stack.imgur.com/f5fZK.png
The big square represent my object layer named : ObjectIt.
My problem is when i touch the square in the simulator it doesn't correspond to the right place. Some people told me problem with float value or open gl but I'm noob i need clear answers .
This is my code :
-(void) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog(#"touch detect");
CCNode* node = [self getChildByTag:TileMapNode];
NSAssert([node isKindOfClass:[CCTMXTiledMap class]], #"not a CCTMXTiledMap");
CCTMXTiledMap* tileMap = (CCTMXTiledMap*)node;
// Get the position in tile coordinates from the touch location
CGPoint touchLocation = [self locationFromTouches:touches];
CGPoint tilePos = [self tilePosFromLocation:touchLocation tileMap:self.tileMap];
// Check if the touch was on water (e.g., tiles with isWater property)
bool isTouchOnWater = NO;
CCTMXObjectGroup* objectLayer = [tileMap objectGroupNamed:#"ObjectIt"];
bool isTouchInRectangle = NO;
int numObjects = [objectLayer.objects count];
for (int i = 0; i < numObjects; i++)
{
NSDictionary* properties = [objectLayer.objects objectAtIndex:i];
CGRect rect = [self getRectFromObjectProperties:properties tileMap:tileMap];
if (CGRectContainsPoint(rect, touchLocation))
{
isTouchInRectangle = YES;
break; }
}
if (isTouchInRectangle)
{
NSLog(#"TOUCH IN RECTANGLE");
// get the ALGORITH FOR TOWERS
}
}
-
(CGPoint) locationFromTouch:(UITouch*)touch
{
CGPoint touchLocation = [touch locationInView: [touch view]];
return [[CCDirector sharedDirector] convertToGL:touchLocation];
}
-(CGPoint) locationFromTouches:(NSSet*)touches
{
return [self locationFromTouch:[touches anyObject]];
}
-(CGRect) getRectFromObjectProperties:(NSDictionary*)dict
tileMap:(CCTMXTiledMap*)tileMap
{
float x, y, width, height;
x = [[dict valueForKey:#"x"] floatValue] + tileMap.position.x;
y = [[dict valueForKey:#"y"] floatValue] + tileMap.position.y;
width = [[dict valueForKey:#"width"] floatValue];
height = [[dict valueForKey:#"height"] floatValue];
return CGRectMake(x, y, width, height);
}
Thats the code , ill give you more if you need.
Also : when i run on the iPhone i got vertical black lines...

Answer 1

In order to get the correct touch location in Cocos2D points use this CCNode convenience method:
- (CGPoint)convertTouchToNodeSpace:(UITouch *)touch
{
CGPoint point = [touch locationInView: [touch view]];
point = [[CCDirector sharedDirector] convertToGL: point];
return [self convertToNodeSpace:point];
}

Answer 2

I'm not sure if it's been added to the API since phix23 posted their answer but the convertTouchToNodeSpace: method basically does the same thing:
-(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event
{
CCTMXTiledMap* tileMap = (CCTMXTiledMap*)[self getChildByTag:TileMapNode];
CGPoint p = [tileMap convertTouchToNodeSpace:touch];
// If you wanted to figure out which tile in a layer they touched (assuming
// it's Ortho) you could do something like this:
CCTMXLayer *layer = [tileMap layerNamed:#"Tile Layer 1"];
CGPoint q = {
(int) (p.x / tileMap.tileSize.width),
// World origin is bottom left but map coordinates are top left so flip
// the y.
layer.layerSize.height - (int) (p.y / tileMap.tileSize.height) - 1
};
CCSprite *s = [layer tileAt:q];
NSLog(#"Touched %#", s);
return YES;
}