Moved "alphamap_fragment" shader chunks immediately after "map_fragment".

This ensures proper alpha testing and avoids other potential issues with deferring alpha map blending until late in the fragment shader.

src/renderers/shaders/ShaderLib.js

@@ -65,12 +65,12 @@ THREE.ShaderLib = {
 
 			THREE.ShaderChunk[ "color_pars_fragment" ],
 			THREE.ShaderChunk[ "map_pars_fragment" ],
+			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "lightmap_pars_fragment" ],
 			THREE.ShaderChunk[ "envmap_pars_fragment" ],
 			THREE.ShaderChunk[ "fog_pars_fragment" ],
 			THREE.ShaderChunk[ "shadowmap_pars_fragment" ],
 			THREE.ShaderChunk[ "specularmap_pars_fragment" ],
-			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "logdepthbuf_pars_fragment" ],
 
 			"void main() {",
@@ -79,13 +79,13 @@ THREE.ShaderLib = {
 
 				THREE.ShaderChunk[ "logdepthbuf_fragment" ],
 				THREE.ShaderChunk[ "map_fragment" ],
+				THREE.ShaderChunk[ "alphamap_fragment" ],
 				THREE.ShaderChunk[ "alphatest_fragment" ],
 				THREE.ShaderChunk[ "specularmap_fragment" ],
 				THREE.ShaderChunk[ "lightmap_fragment" ],
 				THREE.ShaderChunk[ "color_fragment" ],
 				THREE.ShaderChunk[ "envmap_fragment" ],
 				THREE.ShaderChunk[ "shadowmap_fragment" ],
-				THREE.ShaderChunk[ "alphamap_fragment" ],
 
 				THREE.ShaderChunk[ "linear_to_gamma_fragment" ],
 
@@ -175,12 +175,12 @@ THREE.ShaderLib = {
 
 			THREE.ShaderChunk[ "color_pars_fragment" ],
 			THREE.ShaderChunk[ "map_pars_fragment" ],
+			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "lightmap_pars_fragment" ],
 			THREE.ShaderChunk[ "envmap_pars_fragment" ],
 			THREE.ShaderChunk[ "fog_pars_fragment" ],
 			THREE.ShaderChunk[ "shadowmap_pars_fragment" ],
 			THREE.ShaderChunk[ "specularmap_pars_fragment" ],
-			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "logdepthbuf_pars_fragment" ],
 
 			"void main() {",
@@ -189,6 +189,7 @@ THREE.ShaderLib = {
 
 				THREE.ShaderChunk[ "logdepthbuf_fragment" ],
 				THREE.ShaderChunk[ "map_fragment" ],
+				THREE.ShaderChunk[ "alphamap_fragment" ],
 				THREE.ShaderChunk[ "alphatest_fragment" ],
 				THREE.ShaderChunk[ "specularmap_fragment" ],
 
@@ -212,7 +213,6 @@ THREE.ShaderLib = {
 				THREE.ShaderChunk[ "color_fragment" ],
 				THREE.ShaderChunk[ "envmap_fragment" ],
 				THREE.ShaderChunk[ "shadowmap_fragment" ],
-				THREE.ShaderChunk[ "alphamap_fragment" ],
 
 				THREE.ShaderChunk[ "linear_to_gamma_fragment" ],
 
@@ -303,6 +303,7 @@ THREE.ShaderLib = {
 
 			THREE.ShaderChunk[ "color_pars_fragment" ],
 			THREE.ShaderChunk[ "map_pars_fragment" ],
+			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "lightmap_pars_fragment" ],
 			THREE.ShaderChunk[ "envmap_pars_fragment" ],
 			THREE.ShaderChunk[ "fog_pars_fragment" ],
@@ -311,7 +312,6 @@ THREE.ShaderLib = {
 			THREE.ShaderChunk[ "bumpmap_pars_fragment" ],
 			THREE.ShaderChunk[ "normalmap_pars_fragment" ],
 			THREE.ShaderChunk[ "specularmap_pars_fragment" ],
-			THREE.ShaderChunk[ "alphamap_pars_fragment" ],
 			THREE.ShaderChunk[ "logdepthbuf_pars_fragment" ],
 
 			"void main() {",
@@ -320,6 +320,7 @@ THREE.ShaderLib = {
 
 				THREE.ShaderChunk[ "logdepthbuf_fragment" ],
 				THREE.ShaderChunk[ "map_fragment" ],
+				THREE.ShaderChunk[ "alphamap_fragment" ],
 				THREE.ShaderChunk[ "alphatest_fragment" ],
 				THREE.ShaderChunk[ "specularmap_fragment" ],
 
@@ -329,7 +330,6 @@ THREE.ShaderLib = {
 				THREE.ShaderChunk[ "color_fragment" ],
 				THREE.ShaderChunk[ "envmap_fragment" ],
 				THREE.ShaderChunk[ "shadowmap_fragment" ],
-				THREE.ShaderChunk[ "alphamap_fragment" ],
 
 				THREE.ShaderChunk[ "linear_to_gamma_fragment" ],