moved to a layer-based rendermode system, moved normal mode to base primitive

options are now handled partially in the python side, in rendermodes.py

overviewer_core/rendermodes.py

@@ -16,6 +16,29 @@
 from PIL import Image
 import textures
 
+class RenderPrimitive(object):
+    options = {}
+    name = None
+    def __init__(self, **kwargs):
+        if self.name is None:
+            raise RuntimeError("RenderPrimitive cannot be used directly")
+        
+        self.option_values = {}
+        for key, val in kwargs.iteritems():
+            if not key in self.options:
+                raise ValueError("primitive `{0}' has no option `{1}'".format(self.name, key))
+            self.option_values[key] = val
+
+class Base(RenderPrimitive):
+    options = {
+        "edge_opacity": "darkness of the edge lines, from 0.0 to 1.0 (default: 0.15)",
+        "min_depth": "lowest level of blocks to render (default: 0)",
+        "max_depth": "highest level of blocks to render (default: 127)",
+        "height_fading": "darken or lighten blocks based on height (default: False)",
+        "nether": "if True, remove the roof of the map. Useful on nether maps. (defualt: False)",
+    }
+    name = "base"
+
 # Render 3 blending masks for lighting
 # first is top (+Z), second is left (-X), third is right (+Y)
 def generate_facemasks():