Fix drawing of transparent nodes without --drawalpha (fixes #41)

Image.h

@@ -9,6 +9,8 @@ struct Color {
 	Color() : r(0), g(0), b(0), a(0) {};
 	Color(u8 r, u8 g, u8 b) : r(r), g(g), b(b), a(255) {};
 	Color(u8 r, u8 g, u8 b, u8 a) : r(r), g(g), b(b), a(a) {};
+	inline Color noAlpha() const { return Color(r, g, b); }
+
 	u8 r, g, b, a;
 };
 

TileGenerator.cpp

@@ -526,7 +526,7 @@ void TileGenerator::renderMapBlock(const ustring &mapBlock, const BlockPos &pos,
 							continue;
 						}
 					} else {
-						setZoomed(imageX, imageY, c);
+						setZoomed(imageX, imageY, c.noAlpha());
 						m_readPixels[z] |= (1 << x);
 					}
 					if(!(m_readInfo[z] & (1 << x))) {