I've been working on this problem for quite a bit. You can actually put it on the top half of a block level (by placing against the upper half of a block). However, when I do that, the bottom block's texture will not render. I've been trying to fix that but made no results. Until just now I realized something... this bug exists in vanilla Minecraft itself... so without changing the original Minecraft code, I can't think of a way to fix it...
Hmm.. That is very weird. I looked up where the error occurred and I don't seem to find anything that could go wrong. Did the last version work for you? Because that one also has the setup this one has.
I don't mind. I am happy as long as it works out. So I guess something went wrong when I was building/compiling it in gradle? I have rebuilt it, can you please tell me if this one works, if you don't mind. So when I do the next version, everything will work straight away. Thank you in advance.
Attached is version 1.9-0.1.2. Not necessary to update in terms of functions: Simplified block rendering process; removed unused classes/textures... Wanted to get these small stuff out of the way before I create more blocks.