added separate 'zoomLevels' JS config var for marker positioning use (closes #401)

overviewer_core/data/web_assets/overviewer.js

@@ -534,7 +534,7 @@ var overviewer = {
             // the width and height of all the highest-zoom tiles combined,
             // inverted
             var perPixel = 1.0 / (overviewerConfig.CONST.tileSize *
-                Math.pow(2, overviewerConfig.map.maxZoom));
+                Math.pow(2, overviewerConfig.map.zoomLevels));
 
             // This information about where the center column is may change with
             // a different drawing implementation -- check it again after any
@@ -542,13 +542,13 @@ var overviewer = {
 
             // point (0, 0, 127) is at (0.5, 0.0) of tile (tiles/2 - 1, tiles/2)
             // so the Y coordinate is at 0.5, and the X is at 0.5 -
-            // ((tileSize / 2) / (tileSize * 2^maxZoom))
-            // or equivalently, 0.5 - (1 / 2^(maxZoom + 1))
-            var lng = 0.5 - (1.0 / Math.pow(2, overviewerConfig.map.maxZoom + 1));
+            // ((tileSize / 2) / (tileSize * 2^zoomLevels))
+            // or equivalently, 0.5 - (1 / 2^(zoomLevels + 1))
+            var lng = 0.5 - (1.0 / Math.pow(2, overviewerConfig.map.zoomLevels + 1));
             var lat = 0.5;
 
-            // the following metrics mimic those in ChunkRenderer.chunk_render
-            // in "chunk.py" or, equivalently, chunk_render in src/iterate.c
+            // the following metrics mimic those in
+            // chunk_render in src/iterate.c
 
             // each block on X axis adds 12px to x and subtracts 6px from y
             lng += 12 * x * perPixel;
@@ -586,11 +586,11 @@ var overviewer = {
             // the width and height of all the highest-zoom tiles combined,
             // inverted
             var perPixel = 1.0 / (overviewerConfig.CONST.tileSize *
-                Math.pow(2, overviewerConfig.map.maxZoom));
+                Math.pow(2, overviewerConfig.map.zoomLevels));
 
             // Revert base positioning
             // See equivalent code in fromWorldToLatLng()
-            lng -= 0.5 - (1.0 / Math.pow(2, overviewerConfig.map.maxZoom + 1));
+            lng -= 0.5 - (1.0 / Math.pow(2, overviewerConfig.map.zoomLevels + 1));
             lat -= 0.5;
 
             // I'll admit, I plugged this into Wolfram Alpha:

overviewer_core/data/web_assets/overviewerConfig.js

@@ -75,6 +75,12 @@ var overviewerConfig = {
          * This controls how close you can zoom in.
          */
         'maxZoom':      {maxzoom},
+        /**
+         * This tells us how many total zoom levels Overviewer rendered.
+         * DO NOT change this, even if you change minZoom and maxZoom, because
+         * it's used for marker position calculations and map resizing.
+         */
+        'zoomLevels':   {zoomlevels},
         /**
          * Center on this point, in world coordinates. Should be an array, ex:
          * [0,0,0]

overviewer_core/googlemap.py

@@ -114,6 +114,8 @@ class MapGen(object):
                 "{minzoom}", str(0))
         config = config.replace(
                 "{maxzoom}", str(zoomlevel))
+        config = config.replace(
+                "{zoomlevels}", str(zoomlevel))
         
         config = config.replace("{spawn_coords}",
                                 json.dumps(list(self.world.spawn)))

overviewer_core/quadtree.py

@@ -120,7 +120,7 @@ class QuadtreeGen(object):
         indexfile = os.path.join(self.destdir, "overviewerConfig.js")
         if not os.path.exists(indexfile):
             return -1
-        matcher = re.compile(r"maxZoom.*:\s*(\d+)")
+        matcher = re.compile(r"zoomLevels(?:\'|\")\s*:\s*(\d+)")
         p = -1
         for line in open(indexfile, "r"):
             res = matcher.search(line)