[swift-evolution] f suffix for float32 literals, h suffix for float16 literals

[Kelvin Ma]

On Fri, Nov 3, 2017 at 2:05 PM, Steve Canon via swift-evolution <
swift-evolution at swift.org> wrote:

> If/when 16b floats were added to the standard lib, you would just write:
>
>     let vertexData: [Float16] = [ 1, 0, 0.5, 1 ]
>
> I should note that something like vertex coordinates is usually better
> modeled with a more specific type than [Float], like SCNVector4 or
> simd.float4 or your own type, which also solves this problem:
>
>     import SceneKit
>     let vertexData = SCNVector4(1, 0, 0.5, 1)
>
>     import simd
>     let vertexData = float4(1, 0, 0.5, 1)
>
> (NB both of these frameworks are Apple-specific).
>
> - Steve
>
> Sent from my iPhone
>

If @_fixed_layout was supported this would be sensible, but most graphics
frameworks expect a plain buffer of floats and the packing order is
implicit. We can’t model vertex vectors with Swift structs because we can’t
safely pointer-cast them to an array of floats.


>
> On Nov 3, 2017, at 14:58, Tony Allevato via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> You can write this for the first thing that you want:
>
>     let vertexData: [Float] = [1.0, 0.0, 0.5, 1.0]
>
> I don't know enough about 16-bit floats to comment on those.
>
>
> On Fri, Nov 3, 2017 at 11:26 AM nick ralabate via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>> I think it would be helpful for graphics programmers to specify vertex
>> data inline without surrounding every value with Float(4.0).
>>
>> Something like this:
>>
>> let vertexData = [ 1.0f, 0.0f, 0.5f, 1.0f ]
>>
>> Also, it would be great if Swift had a type for half-floats to match the
>> iPhone GPU:
>>
>> let vertexData = [ 1.0h, 0.0h, 0.5h, 1.0h]
>>
>>
>> Thanks!
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