I know this is more a beta question but we are seeing issues with Metal in iOS 13.1 and wanted to know if Apple know about this as for us it's a show stopper.
I have filed a Radar already: FB7153939
If you fire up https://developer.apple.com/documentation/metal/using_a_render_pipeline_to_render_primitives?language=objc and launch it on an iPad running iOS 13.1 the triangle is not an equilaterla triangle as it is on other platforms.
It appears that the following is called twice..
/// Called whenever view changes orientation or is resized
- (void)mtkView:(nonnull MTKView *)view drawableSizeWillChange:(CGSize)size {
NSLog(@"%f %f", size.width, size.height);
// Save the size of the drawable to pass to the vertex shader.
_viewportSize.x = size.width;
_viewportSize.y = size.height;
}
2019-08-29 15:48:29.948467+0100 HelloTriangle[2384:511317] 1668.000000 2388.000000
2019-08-29 15:48:29.968563+0100 HelloTriangle[2384:511317] 3419.000000 1165.000000
Notice how the height and width on the second call are really wide and not that high! This produces a skewed triangle.