Add WebGLInput.jslib for WebGL JS interop plugin

unity-client/Assets/Plugins/WebGLInput.jslib

@@ -0,0 +1,38 @@
+var WebGLInput = {
+  GetURLParam: function(keyPtr) {
+    var key = UTF8ToString(keyPtr);
+    var params = new URLSearchParams(window.location.search);
+    var value = params.get(key) || '';
+    var bufferSize = lengthBytesUTF8(value) + 1;
+    var buffer = _malloc(bufferSize);
+    stringToUTF8(value, buffer, bufferSize);
+    return buffer;
+  },
+
+  OpenFileDialog: function(acceptPtr, callbackObjPtr, callbackMethodPtr) {
+    var accept = UTF8ToString(acceptPtr);
+    var callbackObj = UTF8ToString(callbackObjPtr);
+    var callbackMethod = UTF8ToString(callbackMethodPtr);
+    var input = document.createElement('input');
+    input.type = 'file';
+    input.accept = accept;
+    input.onchange = function(e) {
+      var file = e.target.files[0];
+      if (!file) return;
+      var reader = new FileReader();
+      reader.onload = function(ev) {
+        var base64 = ev.target.result.split(',')[1];
+        SendMessage(callbackObj, callbackMethod, base64);
+      };
+      reader.readAsDataURL(file);
+    };
+    input.click();
+  },
+
+  SetLoadingProgress: function(progress) {
+    var bar = document.getElementById('unity-progress-bar-full');
+    if (bar) bar.style.width = (progress * 100) + '%';
+  }
+};
+
+mergeInto(LibraryManager.library, WebGLInput);