Re: float depth with stencil?

It remains to be seen whether WebGPU would expose a “what does depth24Plus mean on this machine,” but, even if we don’t provide a convenience, it should be observable (if you’re willing to write a few dozen lines of code to actually use the format and detect what kind of precision it has).

>> On Mar 8, 2020, at 4:52 PM, Kai Ninomiya <kainino@google.com> wrote:
> 
> Both questions remain to be answered unfortunately.
> 
>> On Sun, Mar 8, 2020, 2:07 PM Rob Conde <rob.conde@ai-solutions.com> wrote:
>> Thanks for the response (feel free to wait until the weekdays!). Some followup questions:
>> 
>> 1) does it prefer 32 over 24 if available?
>> 2) can you detect which you have?
>> 
>> I'm specifically concerned about implementing a reversed-z depth buffer:
>> 
>> https://nlguillemot.wordpress.com/2016/12/07/reversed-z-in-opengl/
>> 
>> I can fall back to multiple viewing volumes and 24-bit integer depth, but reversed-z is greatly preferred.
>> 
>> Thanks,
>> Rob
>> 
>> From: Kai Ninomiya
>> Sent: Sunday, March 8, 2020 4:53 PM
>> To: Rob Conde
>> Cc: public-gpu
>> Subject: Re: float depth with stencil?
>> 
>> Our "depth24plus" maps to EITHER D24 or D32F. We still haven't worked out how this works with copies etc. though.
>> 
>> On Sun, Mar 8, 2020, 1:52 PM Kai Ninomiya <kainino@google.com> wrote:
>> (Quick response; weekend)
>> 
>> Vulkan spec section:
>> https://renderdoc.org/vkspec_chunked/chap37.html#features-required-format-support
>> 
>> Table 65.
>> 
>> VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT feature must be supported for at least one of VK_FORMAT_X8_D24_UNORM_PACK32 and VK_FORMAT_D32_SFLOAT, and must be supported for at least one of VK_FORMAT_D24_UNORM_S8_UINT and VK_FORMAT_D32_SFLOAT_S8_UINT.
>> 
>> On Sun, Mar 8, 2020, 9:21 AM Rob Conde <rob.conde@ai-solutions.com> wrote:
>> I noticed a lack of something like GL_DEPTH32F_STENCIL8 in the draft spec. 
>> 
>> https://gpuweb.github.io/gpuweb//#dom-gputextureformat-depth32float
>> 
>> Is the lack of a floating point depth buffer + stencil going to be a limitation of WebGPU, or is this accomplished through another means?
>> 
>> Thanks,
>> Rob Conde