From a9518d16d2df89d435f1dfc30e88cedb0e211e51 Mon Sep 17 00:00:00 2001
From: Alejandro Aguilera <fenixin@lavabit.com>
Date: Thu, 1 Mar 2012 19:48:15 +0100
Subject: [PATCH] Add the upside down slab.

---
 overviewer_core/src/primitives/edge-lines.c |  2 +-
 overviewer_core/textures.py                 | 28 +++++++++++++--------
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/overviewer_core/src/primitives/edge-lines.c b/overviewer_core/src/primitives/edge-lines.c
index f708369..dc3d1c1 100644
--- a/overviewer_core/src/primitives/edge-lines.c
+++ b/overviewer_core/src/primitives/edge-lines.c
@@ -40,7 +40,7 @@ edge_lines_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, P
         unsigned short side_block;
 
         int increment=0;
-        if (state->block == 44)  // half-step
+        if (state->block == 44 && ((state->block_data & 0x8) == 0 ))  // half-step BUT no upsidown half-step
             increment=6;
         else if ((state->block == 78) || (state->block == 93) || (state->block == 94)) // snow, redstone repeaters (on and off)
             increment=9;
diff --git a/overviewer_core/textures.py b/overviewer_core/textures.py
index 317d3dd..2d75adf 100644
--- a/overviewer_core/textures.py
+++ b/overviewer_core/textures.py
@@ -1312,22 +1312,25 @@ block(blockid=41, top_index=23)
 block(blockid=42, top_index=22)
 
 # double slabs and slabs
-@material(blockid=[43, 44], data=range(6), transparent=(44,), solid=True)
+@material(blockid=[43, 44], data=range(16), transparent=(44,), solid=True)
 def slabs(self, blockid, data):
-    if data == 0: # stone slab
+    texture = data & 7
+    if texture== 0: # stone slab
         top = self.terrain_images[6]
         side = self.terrain_images[5]
-    elif data == 1: # stone slab
+    elif texture== 1: # stone slab
         top = self.terrain_images[176]
         side = self.terrain_images[192]
-    elif data == 2: # wooden slab
+    elif texture== 2: # wooden slab
         top = side = self.terrain_images[4]
-    elif data == 3: # cobblestone slab
+    elif texture== 3: # cobblestone slab
         top = side = self.terrain_images[16]
-    elif data == 4: # brick?
+    elif texture== 4: # brick
         top = side = self.terrain_images[7]
-    elif data == 5: # stone brick?
+    elif texture== 5: # stone brick
         top = side = self.terrain_images[54]
+    else:
+        return None
     
     if blockid == 43: # double slab
         return self.build_block(top, side)
@@ -1349,10 +1352,15 @@ def slabs(self, blockid, data):
     otherside = ImageEnhance.Brightness(otherside).enhance(0.8)
     otherside.putalpha(othersidealpha)
     
+    # upside down slab
+    delta = 0
+    if data & 8 == 8:
+        delta = 6
+    
     img = Image.new("RGBA", (24,24), self.bgcolor)
-    alpha_over(img, side, (0,12), side)
-    alpha_over(img, otherside, (12,12), otherside)
-    alpha_over(img, top, (0,6), top)
+    alpha_over(img, side, (0,12 - delta), side)
+    alpha_over(img, otherside, (12,12 - delta), otherside)
+    alpha_over(img, top, (0,6 - delta), top)
     
     return img