斜角tmx 地图 根据点击坐标计算tmx坐标算法

 

-(CGPoint) tilePosFromLocation:(CGPoint)location tileMap:(CCTMXTiledMap*)tileMap
{
	// Tilemap position must be subtracted, in case the tilemap position is not at 0,0 due to scrolling
	//如果是retina屏幕，需要将像素乘2
	CGPoint pos = ccpSub(location, tileMap.position);
	float halfMapWidth = tileMap.mapSize.width * 0.5f;
	float mapHeight = tileMap.mapSize.height;
	float tileWidth = tileMap.tileSize.width;
	float tileHeight = tileMap.tileSize.height;
	
	CGPoint tilePosDiv = CGPointMake(pos.x / tileWidth, pos.y / tileHeight);
	float inverseTileY = mapHeight - tilePosDiv.y;

	// Cast to int makes sure that result is in whole numbers, tile coordinates will be used as array indices
	float posX = (int)(inverseTileY + tilePosDiv.x - halfMapWidth);
	float posY = (int)(inverseTileY - tilePosDiv.x + halfMapWidth);

	// make sure coordinates are within isomap bounds
	posX = MAX(0, posX);
	posX = MIN(tileMap.mapSize.width - 1, posX);
	posY = MAX(0, posY);
	posY = MIN(tileMap.mapSize.height - 1, posY);
	
	pos = CGPointMake(posX, posY);

	CCLOG(@"touch at (%.0f, %.0f) is at tileCoord (%i, %i)", location.x, location.y, (int)pos.x, (int)pos.y);
	//CCLOG(@"\tinverseY: %.2f -- tilePosDiv: (%.2f, %.2f) -- halfMapWidth: %.0f\n", inverseTileY, tilePosDiv.x, tilePosDiv.y, halfMapWidth);
	
	return pos;
}

 

算法的解释：http://www.gandraxa.com/isometric_projection.xml