Recently, I saw the best map ever, and it had a menu identical to the main minecraft menu, and I'm trying to replicate it. I believe I have found a way, but it requires more knowledge than the internet is willing to offer. I need to make the 'pumpkinblur' texture to:  
1. Have multiple possible textures, and  
2. Change between these textures based on where I am looking (similar to the rx, rxm, ry, and rym arguments)  
also, why is there no minecraft-resourcepacks/ minecraft-textures tag?