(building) Include slope in RenderContext

Author: ahyangyi

agrf/lib/building/demo.py

@@ -40,6 +40,7 @@ def infer_render_contexts(self):
                         climate=rc.climate or self.climate,
                         subclimate=rc.subclimate or self.subclimate,
                         rail_type=rc.rail_type or self.rail_type,
+                        slope=self.tile_slope(i, j),
                     )
                 )
             ret.append(ret_row)

agrf/lib/building/layout.py

@@ -26,6 +26,7 @@ class RenderContext:
     climate: str = None
     subclimate: str = None
     rail_type: str = None
+    slope: int = None
 
     def dodraw(self, register):
         return True
@@ -396,7 +397,9 @@ def graphics(self, scale, bpp, remap=None, render_context: RenderContext = DEFAU
             return LayeredImage.empty()
         if self.flags.get("dodraw") == Registers.NOSNOW and render_context.subclimate == "snow":
             return LayeredImage.empty()
-        if self.flags.get("dodraw") == Registers.NOSLOPE:
+        if self.flags.get("dodraw") == Registers.NOSLOPE and (
+            render_context.slope != 0 and render_context.slope is not None
+        ):
             return LayeredImage.empty()
         if "dodraw" in self.flags and not render_context.dodraw(self.flags["dodraw"]):
             return LayeredImage.empty()