Demo of using Metal to render EDR/HDR content on iOS platform
MetalEDR-iOS
Demo of using Metal to render EDR/HDR content on iOS platform.
How it works
This demo uses a hack to activate EDR display on iOS platform:
- By setting up an invisible
AVPlayerLayer, and plays short HDR video clip in the backgrond - inspired by https://github.com/kiding/wanna-see-a-whiter-white
Then we can use Metal with a Float Point pixel format to output EDR contents.
Limitation
The "EDR trigger" hack basically has the same effect with metalLayer.wantsExtendedDynamicRangeContent = YES;,
But we still missing APIs like -[NSScreen maximumExtendedDynamicRangeColorComponentValue], so it's very hard to apply appropriate tone-mapping within Metal rendering process.
This demo outputs the raw pixel values loaded by CoreGraphics without applying any tone-mapping, so the colors will clip at current EDR max value and may seems off.