Alphamasking migrated to shaders instead of using fixed-function. Very early code. Hasn't even made it into viewer-development yet.

indra/newview/app_settings/shaders/class1/deferred/shadowAlphaMaskF.glsl

@@ -0,0 +1,27 @@
+/** 
+ * @file shadowAlphaMaskF.glsl
+ *
+ * $LicenseInfo:firstyear=2007&license=viewerlgpl$
+ * $/LicenseInfo$
+ */
+ 
+uniform float minimum_alpha;
+uniform float maximum_alpha;
+
+uniform sampler2D diffuseMap;
+
+varying vec4 post_pos;
+
+void main() 
+{
+	float alpha = texture2D(diffuseMap, gl_TexCoord[0].xy).a * gl_Color.a;
+
+	if (alpha < minimum_alpha || alpha > maximum_alpha)
+	{
+		discard;
+	}
+
+	gl_FragColor = vec4(1,1,1,1);
+	
+	gl_FragDepth = max(post_pos.z/post_pos.w*0.5+0.5, 0.0);
+}