I'm developing a game where the players can drag and drop CCSprites around an Isometric map which is created using the Tiled Map Editor.
To allow automatic vertexZ reordering I have enabled the depthTest option of [CCDirector sharedDirector] in my AppDelegate.
Whenever the CCSprites positions are updated i call this function
- (void)updateVertexZ:(CGPoint)tilePos tileMap:(CCTMXTiledMap *)tileMap
{
float lowestZ = -(tileMap.mapSize.width + tileMap.mapSize.height);
float currentZ = tilePos.x + tilePos.y;
self.vertexZ = lowestZ + currentZ;
}
which correctly reorders the sprites.
Whenever such a sprite is instantiated, I set the shaderProgram like this:
self.shaderProgram = [[CCShaderCache sharedShaderCache]programForKey:kCCShader_PositionTextureColorAlphaTest];
Now, when two sprites are aligned like this (x being a sprite, 0 being empty):
0 x
x 0
and are observed from an Isometric perspective. They are indeed placed correctly. However along the first(closest) sprite a 1px-border is visible - see image. It is the floor in the background - not very cool.
Why is this border visible and how can I get rid of it?
