Unity3D iOS 原生层更新Texture

通过CommandBuffer.IssuePluginCustomTextureUpdate(IntPtr callback, Texture targetTexture, uint userData);
我们可以在原生层更改 UnityTexture 的内容.

原生层的回调：

void TextureUpdateCallback(int eventID, void* data)
{
  auto event = (UnityRenderingExtEventType)eventID;
  auto params = (UnityRenderingExtTextureUpdateParamsV2*)data;
}

eventID ：UnityRenderingExtEventType 中的下面两个 是更新Texture内容相关的

• kUnityRenderingExtEventUpdateTextureBegin
  该事件在更新texture内容之前触发，我们可以这时通过 *data 来更改贴图内容。

    if (event == kUnityRenderingExtEventUpdateTextureBeginV2)
   {
     uint8_t* img = new uint32_t[params->width * params->height * 4];
     // Set image data here.
     params->texData = img;
   }
  

• kUnityRenderingExtEventUpdateTextureEnd,
  该事件在texture内容更新之后触发，我们可以在这里释放资源。

  if (event == kUnityRenderingExtEventUpdateTextureEndV2)
    {
      delete[] reinterpret_cast<uint32_t*>(params->texData);
    }
  

通过下面函数让Unity调用：

extern "C"
UnityRenderingEventAndData UNITY_INTERFACE_EXPORT 
GetTextureUpdateCallback()
{
    return TextureUpdateCallback;
}

以上是原生层相关代码。下面是Unity部分的代码

[DllImport("DllName")] static extern IntPtr GetTextureUpdateCallback();

var callback = GetTextureUpdateCallback();
m_CommandBuffer.IssuePluginCustomTextureUpdateV2(callback, 
texture, userData);
Graphics.ExecuteCommandBuffer(m_CommandBuffer);

可以参考这里 ：https://github.com/keijiro/TextureUpdateExample

我自己在此基础上加入了原生层加载一张图片并设置为Texture内容，代码放到了这里https://code.aliyun.com/shppniu/nativetexture.git，1秒后显示原生加载的图片内容，效果如下：

Kapture 2019-03-24 at 17.42.00.gif

加载图片

[UIImage imageNamed:@"test.png"]]

xcode.png

UIImage转为 Raw Image 读取像素数据

CGImageRef inputCGImage = [image CGImage];
NSUInteger width = CGImageGetWidth(inputCGImage);
NSUInteger height = CGImageGetHeight(inputCGImage);

NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;

//    UInt32 * pixels;
self.pixels = (uint32_t *) calloc(height * width, sizeof(UInt32));

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(self.pixels, width, height,
                                             bitsPerComponent, bytesPerRow, colorSpace,
                                             kCGImageAlphaPremultipliedLast|kCGBitmapByteOrder32Big);

CGContextDrawImage(context, CGRectMake(0, 0, width, height), inputCGImage);

CGColorSpaceRelease(colorSpace);
CGContextRelease(context);

更新Texture内容：

  void TextureUpdateCallback(int eventID, void* data)
 {
    auto event = static_cast<UnityRenderingExtEventType>(eventID);

    if (event == kUnityRenderingExtEventUpdateTextureBegin)
    {
        // UpdateTextureBegin: Generate and return texture image data.
        auto params = reinterpret_cast<UnityRenderingExtTextureUpdateParams*>(data);
        auto frame = params->userData;
        params->texData = PPImgProcesser.sharedInstance.pixels;
    }
    else if (event == kUnityRenderingExtEventUpdateTextureEnd)
    {
        // UpdateTextureEnd: Free up the temporary memory.
        auto params = reinterpret_cast<UnityRenderingExtTextureUpdateParams*>(data);
        //delete[] reinterpret_cast<uint32_t*>(params->texData);
    }

}