Is wgpuSurfaceGetPreferredFormat redundant with WGPUSurfaceCapabilities.formats[0]?

[kainino0x]

Since @beaufortfrancois is trying to port some samples, I realized we probably should list the preferred format as formats[0]. Otherwise it's not obvious that formats[0] might give you the wrong format and you need to call GetPreferredFormat instead.

GetPreferredFormat is already planned to become extensible (#216) so it can take extra options into account unlike formats[0], but in the near term it won't actually have any extra options, so maybe there's no reason to have it at all yet. We can add the function once it actually has extra options.

[Kangz]

I'd definitely be in favor of removing it for now!

[kainino0x]

After reviewing some code using this, I do think it's a little bit of a magic incantation to use formats[0] to get the preferred format. But probably not a big deal, compared with being redundant/unclear about how you should do things.

[kainino0x]

May 23 meeting (sorry for delay):

• AE/KN: Both in favor of doing this
• CF: me too
• KN: eventually JS spec may have srgb, hdr, etc.
• AE: Can you get this information by just filtering and looking for first match?
• KN: Probably? If you filter to a format that you need, then the first one you get should be the preferred one? Could use this as a basic heuristic?
• AE: What about WASM? Would we get only the JS-allowed format?
• KN: Yea, but there’s 3 formats, so ordering would tell us what's the preferred one.
• Remove wgpuSurfaceGetPreferredFormat, formats[0] is preferred.

[yig]

If wgpuSurfaceGetPreferredFormat() is coming back with an extra options struct, perhaps it can be left in place with a placeholder nullable WGPUSurfaceGetPreferredFormatOptions struct parameter? It is much more pleasant to write

    .format = wgpuSurfaceGetPreferredFormat( surface, adapter, nullptr ), // Sokol-style designated initializer

versus

WGPUSurfaceCapabilities capabilities;
wgpuSurfaceGetCapabilities( surface, adapter, &capabilities );
something.format = capabilities.formats[0];
wgpuSurfaceCapabilitiesFreeMembers( capabilities );

[kainino0x]

I don't think it is coming back very soon, as it will be some time before the JS API has any arguments to getPreferredCanvasFormat(), and we're planning to stabilize webgpu.h before that.

[Kangz]

Done in #319.