How to continuously check collisions in Tiled tilemaps during a CCMoveTo - ios

Question

Hello good people of stack overflow
I stand before you today with a (not very great) cocos2d issue.
How can I check collisions WHILE in an action, instead of checking the target tile?
I am working with a tilemap that has a meta layer where there are collidable tiles. The following code works when I click the collidable tile, but not when I click beyond it, if that happens he will just walk straight through.
Currently, I detect collisions with this code:
-(void)setPlayerPosition:(CGPoint)position {
CGPoint tileCoord = [self tileCoordForPosition:position];
int tileGid = [_meta tileGIDAt:tileCoord];
if (tileGid) {
NSDictionary *properties = [_tileMap propertiesForGID:tileGid];
if (properties) {
NSString *collision = properties[#"Collidable"];
if (collision && [collision isEqualToString:#"True"]) {
return;
}
}
}
float speed = 10;
CGPoint currentPlayerPos = _player.position;
CGPoint newPlayerPos = position;
double PlayerPosDifference = ccpDistance(currentPlayerPos, newPlayerPos) / 24;
int timeToMoveToNewPostition = PlayerPosDifference / speed;
id moveTo = [CCMoveTo actionWithDuration:timeToMoveToNewPostition position:position];
[_player runAction:moveTo];
//_player.position = position;
}
By the way, this gets called from this method:
-(void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event
{
[_player stopAllActions];
CGPoint touchLocation = [touch locationInView:touch.view];
touchLocation = [[CCDirector sharedDirector] convertToGL:touchLocation];
touchLocation = [self convertToNodeSpace:touchLocation];
CGPoint playerPos = _player.position;
CGPoint diff = ccpSub(touchLocation, playerPos);
int diffx = diff.x;
int diffy = diff.y;
int adiffx = diffx / 24;
int adiffy = diffy / 24; //Porque my tile size is 24
if ( abs(diff.x) > abs(diff.y) ) {
if (diff.x > 0) {
playerPos.x = playerPos.x + adiffx * 24;
} else {
playerPos.x = playerPos.x + adiffx * 24;
}
} else {
if (diff.y > 0) {
playerPos.y = playerPos.y + adiffy * 24;
}else{
playerPos.y = playerPos.y + adiffy * 24;
}
}
[self setPlayerPosition:playerPos];
}
I tried
[self schedule:#selector(setPlayerPosition:) interval:0.5];
Without any luck, that just instantly crashed the app at this
NSAssert( pos.x < _layerSize.width && pos.y < _layerSize.height && pos.x >=0 && pos.y >=0, #"TMXLayer: invalid position");
And i can't really blame it for crashing there.
How do I constantly check for collisions with the collidable meta tiles while a CCMoveTo is running?

Answer 1

In your init, schedule a collision detecting method:
[self schedule:#selector(checkCollisions:)];
Then define it as follows:
-(void)checkCollisions:(ccTime)dt
{
CGPoint currentPlayerPos = _player.position;
CGPoint tileCoord = [self tileCoordForPosition:currentPlayerPos];
int tileGid = [_meta tileGIDAt:tileCoord];
if (tileGid)
{
NSDictionary *properties = [_tileMap propertiesForGID:tileGid];
if (properties)
{
NSString *collision = properties[#"Collidable"];
if (collision && [collision isEqualToString:#"True"])
{
[_player stopAllActions];
return;
}
}
}
}

Answer 2

I using a similar meta layer. I personally skipped using MoveTo, and created my own update code that both moves the sprite and does collision detection.
I figure out what the potential new position would be, then I find out what tile position is in all four corners of the sprite at that new position, then I cycle through all tiles that the sprite would be on and if any are collidable, I stop the sprite.
I actually go a step further and check if moving only the x, or only the y changes the results, then move to that position instead if it does.