north current
I have a WebGL context, created with powerPreference option:
const gl = canvas.getContext('webgl2', {
powerPreference: 'high-performance',
});
in Safari, after disabling "WebGL via Metal" experimental feature, it switches to discrete GPU, but in Tauri this isn't the case
I thought Safari tells WebKit somehow to disable Metal, so looked for some docs:
https://trac.webkit.org/wiki/FeatureFlags
https://trac.webkit.org/wiki/EnvironmentVariables
but there's no such thing there
slender cove
I'm not an expert on WebGL or WebKit's use of it. The WebGL specification (which WebGL 2.0 inherits from) describes powerPreference as "only a hint and a WebGL implementation may choose to ignore it" (https://registry.khronos.org/webgl/specs/latest/1.0/#5.2.1). If I'm reading the inferences of the patch for WebKit Bug 229267 (https://bugs.webkit.org/show_bug.cgi?id=229267) correctly, it sounds like WebKit doesn't directly concern itself too much with webgl2 and only concentrates on webgl; this might be related to their 2021 switch to Google's ANGLE (https://trac.webkit.org/wiki/AngleforWebGL). It's quite possible that Safari invokes a flag that is not documented in WebKit but in ANGLE. After taking a brief look at ANGLE, I found EGL_ANGLE_power_preference.txt (https://github.com/google/angle/blob/251ba5cb119ff2fed0e861cbc9b096c45004c1fa/extensions/EGL_ANGLE_power_preference.txt) which states that "[t]he containing application must set the NSSupportsAutomaticGraphicsSwitching attribute to true in its Info.plist in order for this extension to operate as advertised."