I'm trying to integrate WKWebView to metal rendering pipline and met 2 issues.
WKWebView will kick webview rendering only when the WKWebView control is visible, i have been looking around WKWebView related header files and configurations, didn't find a way to force WkWebView render the view for every single frame when the control is invisible or not part of view hierarchy .
Low performance when access CGImage pixel data returned from WKWebview takesnapshot, in order to get the pixel data uploaded to MTLTexture i did the following tests:
Access the pixel data through CGDataProviderCopyData, the CPU usage is very high, main thread drop to 37 FPS on IPhone 8 Plus simulator, most CPU cycles spend on function vConvert_PermuteChannels_ARGB8888_CV_vec, i also try to render the CGImage to a BitmapContext but still can't get ride of vConvert_PermuteChannels_ARGB8888_CV_vec.
CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
CFDataRef rawData = CGDataProviderCopyData( provider );
CFIndex length = CFDataGetLength( rawData );
UInt8 *buf = (UInt8*) CFDataGetBytePtr( rawData );
MTLRegion region = {
{0, 0, 0},
{1280, 960, 1}
};
[_webviewTexture replaceRegion:region mipmapLevel:0 withBytes:buf bytesPerRow:bytesPerRow];
CFRelease( rawData );
Another try is create metal texture from CGImage via textureLoader but failed with error "image decoding failed"
MTKTextureLoader *loader = [[MTKTextureLoader alloc] initWithDevice: _device];
NSDictionary *textureLoaderOption = @{
MTKTextureLoaderOptionTextureUsage:@(MTLTextureUsageShaderRead),
MTKTextureLoaderOptionTextureStorageMode : @(MTLStorageModePrivate)
};
NSError *error = nil;
_webviewTexture = [ loader newTextureWithCGImage:cgImage options:textureLoaderOption error:&error];
Any idea against how to force kick WebView rendering or more efficient way to access CGImage raw pixel data would be greatly appreciated.