Create/Update assets for version 1.12.1

assets/minecraft/shaders/program/outline_combine.fsh

@@ -0,0 +1,13 @@
+#version 120
+
+uniform sampler2D DiffuseSampler;
+uniform sampler2D OutlineSampler;
+
+varying vec2 texCoord;
+varying vec2 oneTexel;
+
+void main(){
+    vec4 diffuseTexel = texture2D(DiffuseSampler, texCoord);
+    vec4 outlineTexel = texture2D(OutlineSampler, texCoord);
+    gl_FragColor = vec4(diffuseTexel.rgb + diffuseTexel.rgb * outlineTexel.rgb * vec3(0.75), 1.0);
+}