从Texture2D创建UI图像

Question

I working on a live stream App that receives JPEG image as arrays of bytes and displays it on the screen with UI.Image . It works fine but I am making optimization and have few questions . Currently, the code I have below converts arrays of bytes to Texture2D then creates a Sprite from the Texture2D then assign that Sprite to UI.Iamge to display on the screen.

Texture2D camTexture;
Image screenDisplay;
public byte[] JPEG_VIDEO_STREAM;
bool updateScreen = false;

//Initializing

JPEG_VIDEO_STREAM = new byte[20000];
camTexture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, false);

//Main Code that runs in the Update function

if(updateScreen){
camTexture.LoadImage(JPEG_VIDEO_STREAM);
Sprite tempSprite = Sprite.Create(camTexture, new Rect(0, 0, camTexture.width, camTexture.height), Vector2.zero, 0);
screenDisplay.sprite = tempSprite;
updateScreen = false;
}

The code above currently perform 3 steps just to display image to screen.

byte array -> Texture2D -> Sprite -> UI.Image .

but I want it to look like byte array -> Texture2D -> UI.Image .

I want to write Texture2D directly to UI.Image without creating new Sprite because I believe that Sprite.Create(camTexture, new Rect(0, 0, camTexture.width, camTexture.height), Vector2.zero, 0); allocates new memory each time Sprite.Create called. I looked at the Unity Documentation and couldn't find any other way to do this.

My questions are:

1. How can I assign camTexture(Texture2D) to the screen screenDisplay(UI.Image) without converting camTexture(Texture2D) to Sprite first?

2. Does Sprite.Create allocate new memory when called?

3. If there is a solution to this, is that solution better than what I currently have in terms of performance and memory management ?

Note: I have no plans on using OnGUI to draw Texture2D . I want to do this with the new Unity UI . Thanks.

Edit: With Joe's answer of RawImage, the final code looks like this:

RawImage screenDisplay;
if(updateScreen){
camTexture.LoadImage(JPEG_VIDEO_STREAM);
screenDisplay.texture = camTexture;
updateScreen = false;
}

No more Sprite needed.

Answer 1

I think that by specifically using a RawImage rather than Image , one can do this.

I use RawImage extensively, because, we have to "display PNGs" and it's easier.

Consider the very handy trick:

just start with a trivial gray PNG which you have imported .. and then modify that .. rather than try to build from scratch?

An interesting curiosity I found is: normally to mirror an image, you just simply scale of x or y to -1. Unless it's been fixed, Unity has a problem where this won't work for RawImage .

    // currently in Unity, the ONLY way to mirror a RAW image is by fooling with
    // the uvRect. changing the scale is completely broken.

    if ( shouldWeMirror )
      rawImage.uvRect = new Rect(1,0,-1,1); // means mirror
    else
      rawImage.uvRect = new Rect(0,0,1,1);  // means no flip

Another interesting factor. For this reason, many Unity projects still use (even 2017) the superlative 2dToolkit . It instantly solves issues such as this.