There is a problem with tile map coordinate It read reversely ??(Latest Cocos2d)

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There is a problem with tile map coordinate It read reversely ??(Latest Cocos2d)

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Started 2 years ago by artakus
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artakus
Member

Hello all, Im having problem with the tile map coordinate. It reads reversely.

Here is my code:

TMXTiledMap *map = [TMXTiledMap tiledMapWithTMXFile:@"level1.tmx"];
[self addChild:map];
Sprite *soldier = [Sprite spriteWithFile:@"archer_front_01.png"];
[self addChild:soldier];
TMXLayer *layer = [map layerNamed:@"Layer 0"]; //

AtlasSprite *tile = [layer tileAt:ccp(0,1)]; // <------------ When i try to print the location of this, it will return reverse coordinate

for example I NSLog out this:

NSLog(@"TileX: %f TileY: %f", tile.position.x, tile.position.y); <-----It should come out with tileMap position but it print ccp. Any helps?

Posted 2 years ago #
riq
Key Master

I don't understand the bug.
What's the expected behavior ? What do you see instead ?

Posted 2 years ago #
artakus
Member

My Map Tile Size = 32. I'm using tile object to retrieve map coordinate. I write like this:

TMXTiledMap *map = [TMXTiledMap tiledMapWithTMXFile:@"level1.tmx"];
[self addChild:map];
TMXLayer *layer = [map layerNamed:@"Layer 0"];
AtlasSprite *tile = [layer tileAt:ccp(0,1)];

How do I print tile object and return it same as 0,1 like code above? I use NSLog(@"TileX: %.f TileY: %.f", tile.position.x, tile.position.y); and it return in ccp format.

The output:

TileX: 0 TileY: 256 <---- Why (0, 256) not (0, 32) ?

It should return (0,32) NOT (0,256) right??. Is this bug?

Then after that I converted the ccp format into TilebaseMap coordinate by using formula

float newX = floor(tile.position.x/32);
float newY = floor(tile.position.y/32);

NSLog(@"tileX: %.f, tileY: %.f", newX, newY);

And then how come it return 0,8? It should return same value as the code (0,1).

Posted 2 years ago #
artakus
Member

bump

Posted 2 years ago #
riq
Key Master

it should return the position relative to it's parent, like any other CocosNode, so (0,256) is correct.

Please, read this document:
http://www.cocos2d-iphone.org/wiki/doku.php/prog_guide:tiled_maps

The wiki explains that it returns an AtlasSprite. You can move it freely, like any node.

If the wiki does not explain this issue correctly, could you edit it and add/modify/remove the needed documentation ? Thanks.

Posted 2 years ago #
artakus
Member

I already read the documentation and found usefull information. But that still doesn't help my problem.

All right you said it is correct, so can you explain what does it mean by writing coordinate (0,1) in this statement?

AtlasSprite *tile = [layer tileAt:ccp(0,1)];

If the return (0,256)is correct, Why not write the statement like this?

AtlasSprite *tile = [layer tileAt:ccp(0,8)];

if (0,8) = tile coordinate, then should be (0,256) = ccp coordinate right ? (after convert using 32 tile size)

Here is my situation. I wanna set obstacle in my map so each tile should have its own value (coordinate). The problem is, my map can be moved! so I have to read the map coordinate and set it as obstacle. I cannot use ccp coordinate because it just for iphone screen not for the map.

To retrieve the tile coordinate, I use above statement but It return reverse value. Any help please..? Just need to read the coordinate and return its value.

Posted 2 years ago #
riq
Key Master

sorry, I don't understand your problem :-(

Could you write a working example, and explain what is wrong with your example ? Thanks.

Posted 2 years ago #
chrisco
Member

@artakus -

float newX = floor(tile.position.x/32);
float newY = floor(tile.position.y/32);

^^^ This code that you're using assumes that tile 0,0 is located at the bottom-left of your tilemap, but according to the link that Riq posted, the tiles in a tilemap begin with tile 0,0 at top-left.

So I may be mistaken, but I think your confusion is in the coordinate system of the tilemap. If you have a map that matches screen size filled with 32 pixel tiles, tile 0,0 of the map is an AtlasSprite placed at 0,288, tile 0,1 would be an AtlasSprite at 0,256 and so on.

Posted 2 years ago #
artakus
Member

@chrisco
Is there a way how to retrieve the map coordinate using the formula? So it seem the formula doesn't match with the map

Posted 2 years ago #
chrisco
Member
Well, assuming I'm not pointing you in completely the wrong direction (someone feel free to step in if I am :), your formula for evaluating the x position is fine, as both coordinate systems go from left to right.

And while there is probably a way to mathematically correct the y value, I can't really think of what it is right now. A quick fix would be an array that can quickly reverse the values:
```
float newX = floor(tile.position.x/32); // this one is correct

float newY = floor(tile.position.y/32); // use this to get the Y value based on tile position with bottom-left coords
int correctedYValues[10] = {9,8,7,6,5,4,3,2,1,0}; // assuming there are 10 rows in your map
newY = correctedYValues[newY]; // reverses the value of newY for top-left coordinate system
```
Like I said, there's undoubtedly a better way to do this - at the moment I'm doing something so non-math related, my head's not in the right space to figure it out :P This should work though if you're stuck.

Chris
Posted 2 years ago #
artakus
Member

@Chris. It looks like going to work. Great idea but I still got the same ouput

TMXLayer *layer = [map layerNamed:@"Layer 0"];
AtlasSprite *tile = [layer tileAt:ccp(0,1)];

int newX = floor(tile.position.x/32);
int newY = floor(tile.position.y/32);

NSLog(@"Before CONVERT -> tileX: %.f, tileY: %.f", newX, newY);

//Convert
int correctedYValues[10] = {9,8,7,6,5,4,3,2,1,0};
newY = correctedYValues[newY];

NSLog(@"After CONVERT -> tileX: %.f, tileY: %.f", newX, newY);

OUTPUT:
Before CONVERT: tileX: 0, tileY: 256
After CONVERT: tileX: 0, tileY: 256

Before AND After convert output are both same. :-(. Any mistake i've made?

Posted 2 years ago #
artakus
Member

hey sorry i think i miss something the newX and newY is float :D. My bad! it works! Thanks for your help! :D.

Posted 2 years ago #

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