Implementing Sharing in Cocos2d-x: A Deep Dive into UIActivityViewController and CCRenderTexture

Cocos2d-x is a popular open-source game engine for creating 2D games on multiple platforms. As a new developer, you may have come across the task of implementing sharing functionality in your game, such as sharing images or screenshots on social media platforms like Facebook and Gmail. In this article, we will delve into the technical details of how to achieve this using Cocos2d-x’s UIActivityViewController and CCRenderTexture.

Understanding UIActivityViewController

The UIActivityViewController is a class in Apple’s iOS SDK that provides a convenient way to present a sharing dialog to the user. It allows you to specify the items to be shared, as well as which activities to exclude from the list.

Here’s an overview of how it works:

1. Create an instance of UIActivityViewController.
2. Set the activityItems property to the items to be shared.
3. Optionally set the applicationActivities property to specify additional activities to include in the sharing dialog.
4. Call the presentViewController:animated:completion: method to present the sharing dialog.

In our example, we’ll use the UIActivityViewController to create a sharing popup that allows users to share an image and some text.

Understanding CCRenderTexture

CCRenderTexture is a class in Cocos2d-x that provides a convenient way to capture screenshots of a node or a subgraph within the game’s scene hierarchy. It allows you to render a texture from a specific region of the screen, which can be useful for capturing images or videos.

Here’s an overview of how CCRenderTexture works:

1. Create an instance of CCRenderTexture.
2. Set the width and height properties to specify the region of the screen to capture.
3. Call the begin() method to start rendering.
4. Render the desired content within the specified region using a node or subgraph.
5. Call the end() method to finish rendering.
6. Get the captured texture as a UIImage.

In our example, we’ll use CCRenderTexture to take a screenshot of the game’s scene and capture it for sharing purposes.

Implementing Sharing in Cocos2d-x

To implement sharing in Cocos2d-x, we’ll follow these steps:

1. Create an instance of UIActivityViewController.
2. Set the activityItems property to an array containing the captured screenshot and some text.
3. Optionally set the applicationActivities property to exclude certain activities from the list.
4. Call the presentViewController:animated:completion: method to present the sharing dialog.

Here’s a sample code snippet that demonstrates how to implement sharing in Cocos2d-x:

func openShareDialog() {
    let scene = CCDirector.sharedDirector().runningScene
    let node = scene.children[0]
    let screenshot = takeScreenshotWithNode(node)
    
    let sharedText = "Text"
    let itemsToShare = [screenshot, sharedText]
    
    var excludedActivities = [
        UIActivityTypeAssignToContact,
        UIActivityTypeAddToReadingList,
        UIActivityTypePostToTencentWeibo
    ]
    
    let controller = UIActivityViewController(activityItems: itemsToShare, applicationActivities: nil)
    controller.excludedActivityTypes = excludedActivities
    
    UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(controller, animated: true, completion: nil)
}

func takeScreenshotWithNode(node: CCNode) -> UIImage {
    CCDirector.sharedDirector().nextDeltaTimeZero = true
    let viewSize = CCDirector.sharedDirector().viewSize()
    let rtx = CCRenderTexture(width: Int32(viewSize.width), height: Int32(viewSize.height))
    rtx.begin()
    node.visit()
    rtx.end()
    return rtx.getUIImage()
}

Capturing the Screenshot

To capture a screenshot of the game’s scene, we’ll use CCRenderTexture. Here’s an overview of how it works:

1. Create an instance of CCRenderTexture with the desired width and height.
2. Call the begin() method to start rendering.
3. Render the desired content within the specified region using a node or subgraph.
4. Call the end() method to finish rendering.
5. Get the captured texture as a UIImage.

In our example, we’ll use CCRenderTexture to take a screenshot of the game’s scene and capture it for sharing purposes.

Presenting the Sharing Dialog

To present the sharing dialog, we’ll create an instance of UIActivityViewController and call the presentViewController:animated:completion: method. Here’s an overview of how it works:

1. Create an instance of UIActivityViewController.
2. Set the activityItems property to an array containing the captured screenshot and some text.
3. Optionally set the applicationActivities property to exclude certain activities from the list.
4. Call the presentViewController:animated:completion: method to present the sharing dialog.

In our example, we’ll use UIActivityViewController to create a sharing popup that allows users to share an image and some text.

Conclusion

Implementing sharing in Cocos2d-x involves using UIActivityViewController to create a sharing dialog and CCRenderTexture to capture screenshots of the game’s scene. By following these steps, you can provide your players with a convenient way to share their favorite moments from your game on social media platforms like Facebook and Gmail.

Additional Resources

• Apple’s UIActivityViewController documentation: https://developer.apple.com/library/archive/documentation/UIKit/Reference/UIActivityViewController_class/index.html
• Cocos2d-x CCRenderTexture documentation: <https://www.cocos2d-ux.net/doc/cocos2d-x/user-guide/ rendering/texture-rendering.html>

Last modified on 2023-10-22