add 'u_alphaClip' to the blocks shader

res/shaders/main.glslf

@@ -9,14 +9,14 @@ uniform samplerCube u_cubemap;
 uniform vec3 u_fogColor;
 uniform float u_fogFactor;
 uniform float u_fogCurve;
+uniform bool u_alphaClip;
 
 void main() {
     vec3 fogColor = texture(u_cubemap, a_dir).rgb;
     vec4 tex_color = texture(u_texture0, a_texCoord);
     float depth = (a_distance/256.0);
     float alpha = a_color.a * tex_color.a;
-    // anyway it's any alpha-test alternative required
-    if (alpha < 0.3f)
+    if (u_alphaClip && alpha < 0.9f)
         discard;
     f_color = mix(a_color * tex_color, vec4(fogColor,1.0), 
               min(1.0, pow(depth*u_fogFactor, u_fogCurve)));