I tried using the shader from http://www.blog.radiator.debacle.us/2013/09/hacking-blend-transition-masks-into.html, and something is certainly happening but not as intended. The grass texture (alpha channel) has a yellowish outline on it when it's painted. https://gyazo.com/e40157bfea9285b7f321cf2b213b1dd9 and here's what…