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Overview

Communication means refers to the transmission of data between two people individuals or entities. Where one will send data and another one will receive it , where one sends data and the other receives it, and vice versa.

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1

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. Sending data from the parent

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Webpage to the Unreal App

To communicate with the unreal app, you must should send data from the webpage to the unreal app and the app will send you a response. Data

To send Integer data, we have to convert the integer into a string using the toString()method.

To send a JSON object, we have to should stringify it using the JSON.stringify() method.

For an array, we need to convert it to a JSON object and then stringify the object.

Below is an example of how to send JSON data from the webpage to the unreal app.

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let descriptor = {
		Teleport: "6"
	};
let obj = {
	cmd: "sendToUe4",
	value: descriptor
}
document.getElementById("iframe_1").contentWindow.postMessage(JSON.stringify(obj), "*");
//here "iframe_1" is the id of the HTML iframe element

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2

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. Manipulating the style attribute of an HTML element

This can also be achieved by sending data from the webpage . But but we need to make a few changes in the JSON object for that.

Here’s an example that hides the settings button inside within the streaming UI:

const toggleSettings = (id)=>{

    let descriptor = {
        id,
        property: 'display',
        value: 'none'
    };
    let obj =
        {
            cmd: "style",
            value: descriptor,
        }
    document.getElementById("iframe_1").contentWindow.postMessage(JSON.stringify(obj), "*");
}

Here id is the ID of the HTML element whose style you are trying to change.

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3. Receiving data from the Unreal App to the parent

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Webpage

After sending the data we will receive a response from the unreal app.

This response can be caught by using window.e3ds.onEvent function. Here’s an message event handler defined in the page .

Below is a detailed example of that - :

function HandleResponseFromUE4(jsonObj) {
  // Process the JSON object sent by the Unreal app to the webpage
  console.log(jsonObj);

  if (window.e3ds.events[jsonObj.cmd]) {
  

window.e3ds.events[jsonObj.cmd](jsonObj);
  }
}


const eventHandler = (event) => {
  // This function will receive all kinds of events the webpage receives
  
  // Check if event.data.type exists to identify if it was sent by the Unreal app
  if (!event.data.type) {
    // If event.data includes a field named cmd, then this data is coming from the Unreal app.
    // If your Unreal app uses a different field name, replace this field name with the one you have used in your Unreal app
    if (typeof event.data === 'string' && event.data.includes('cmd')) {
      // We are sendingreceiving data as a string. Now we try to parse it to check
      // if this string represents a JSON or not.
      // If you are sending a normal string from the Unreal app, then this is not needed 

      const parsedData = JSON.parse(event.data);
      if (parsedData.cmd) { // It is JSON object data sent from UE4
        HandleResponseFromUE4(parsedData); // Process the data sent by UE4
      }
    }
  }
  else{
		//data sent from server
		messageHandler(event);

	}
}
// We are binding eventHandler to receive all kinds of messages the webpage receives
window.addEventListener("message", eventHandler);

Part-4 :
Set Custom Resolution from Webpage with Iframe

Go to the following document to learn about how to set custom resolution from your webpage.

Part-5:
How to send a Pixel Streaming Response from unreal app to webpage

Useful Events:

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4. Receiving Non-Unreal Data from an Iframe on a Webpage

If a message doesn’t contain event.data.type, it is sent to messageHandler function.

See this document to learn different types of event sent to messageHandler.

const messageHandler = (event) => {
	const loaderStep1 = document.getElementById("loaderStep1");
	const loaderStep2 = document.getElementById("loaderStep2");
	const loaderStep3 = document.getElementById("loaderStep3");
	const iframeElem = document.getElementById("iframe_1");
	const sidebar = document.getElementById("sidebar");


	console.log("received data event type " + event.data.type)
	switch (event.data.type) {
		case "ResponseFromUE4":
			console.log("UE4->iframe: " + event.data.descriptor)
			myHandleResponseFunction(event.data.descriptor);
			break;
		case "stage1_inqueued":
			loaderStep1.style.visibility = "visible";
			break;
		case "stage2_deQueued":
			// loading screen 1 hides
			break;
		case "stage3_slotOccupied":
			loaderStep1.style.display = "none";
			loaderStep2.style.visibility = "visible";
			break;
		case "stage4_playBtnShowedUp":
			//loading screen 2 hides
			loaderStep2.style.visibility = "hidden";
			iframeElem.style.visibility = "visible";
			// loaderStep3.style.visibility = "visible";
			let playButton = document.getElementById("playButtonParent");
			playButton.click();
			onPlayBtnPressed();
			break;
		case "stage5_playBtnPressed":
			sidebar.style.visibility = "visible";
			loaderStep2.style.display = "none";
			iframeElem.style.visibility = "visible";
			$('#iframe_1').focus();
			break;
		case "_focus":
			document.getElementById("iframe_1").focus();
			break;
		case "isIframe":
			let obj = {
				cmd: 'isIframe',
				value: true
			};
			document.getElementById("iframe_1").focus();
			document.getElementById("iframe_1").contentWindow.postMessage(JSON.stringify(obj), "*");;
			break;
			
		case "QueueNumberUpdated":
			console.log("QueueNumberUpdated. New queuePosition: : " +  event.data.queuePosition)
			break;
			
		case "stage3_1_AppAcquiringProgress":
			console.log("stage3_1_AppAcquiringProgress percent: " + JSON.stringify( event.data.percent))
			break;
			
		case "stage3_2_AppPreparationProgress":
			console.log("stage3_2_AppPreparationProgress percent:" + JSON.stringify( event.data.percent))
			break;	
		case "shortCuts":
			console.log("Key pressed");
			break;
		case "Error_Redirect":
			loaderStep2.style.display = "none";
			iframeElem.style.visibility = "visible";
			$('#iframe_1').focus();
		default:
			console.error("Unhandled message data type");
			break;
	}
}

5. Setting a Custom Resolution via an Iframe on a Webpage

Refer to this document to learn how to set a custom resolution on your webpage.

6. Sending a Pixel Streaming Response from the Unreal App to the Webpage

Refer to this document.

Useful Events

See this document for Useful Events in Iframe Solution.

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Need help? Contact Support

If you still need help, contact support to get your issue resolved quickly.

Submit a new request at E3DS support portal or send an Email at support@eagle3dstreaming.com.Seek advice. Connect with others. Share your experiences. Join our lively Community Forum today.

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