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Re: [Public WebGL] retrograde webgl support levels



Are these native numbers what the GPU supports, or what the iOS GLES2
driver exposes? I don't have access to an iPhone6, but on the iPhone6
*simulator* a native GLES2 context exposes the same limits as the
WebGL implementation (with iOS8.1):

GL_MAX_TEXTURE_SIZE: 4096
GL_MAX_CUBE_MAP_TEXTURE_SIZE: 4096
GL_MAX_VIEWPORT_DIMS: 4096 4096
GL_MAX_VERTEX_ATTRIBS: 16
GL_MAX_VERTEX_UNIFORM_VECTORS: 128
GL_MAX_VARYING_VECTORS: 8
GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS: 8
GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS: 8
GL_MAX_FRAGMENT_UNIFORM_VECTORS: 64

My Gen4 iPad is the same (on the device, not simulator). I haven't
checked OpenGLES3 yet on the iPhone6 simulator.

Cheers,
-Floh.

On Tue, Oct 28, 2014 at 2:36 PM, Florian Bösch <pyalot@gmail.com> wrote:
> On Tue, Oct 28, 2014 at 2:11 PM, Mark Callow <khronos@callow.im> wrote:
>>
>> Do you have any suggestions on how to deal with this? I believe the WebGL
>> implementations reflect the limits of the underlying implementation.
>
> These parameters are only represented at the lower end by relatively few
> android devices (most androids, often by more than 3/4 support the higher
> values.
>
> My iPad mini retina natively supports:
>
> MAX_VERTEX_UNIFORM_VECTORS: 512 (384 more than webgl)
> MAX_COMBINED_TEXTURE_IMAGE_UNITS: 32 (24 more than webgl)
> MAX_TEXTURE_IMAGE_UNITS: 16 (8 more than webgl)
>
> My iPod touch 5tg gen supports:
>
> MAX_VERTEX_UNIFORM_VECTORS: 128 (0 more than webgl)
> MAX_COMBINED_TEXTURE_IMAGE_UNITS: 8 (0 more than webgl)
> MAX_TEXTURE_IMAGE_UNITS: 8 (0 more than webgl)
>
> So the constraints do not reflect hardware constraints outright on some
> devices, particularly not the newer ones. I've detailed this fact on this
> blog post
> http://codeflow.org/entries/2014/jun/08/some-issues-with-apples-ios-webgl-implementation/#hardcoded-constraints-on-ios
> . See also this webkit ticket https://bugs.webkit.org/show_bug.cgi?id=133745
>
> I understand Apples desire to support older devices and not fragment their
> own ecosystem with different capabilities (or perhaps it's just
> implementation convenience). However, in the act of doing so, they're
> fracturing the larger WebGL ecosystem, in particular, any application
> written in WebGL in the last 3 years that bumps against the practical lower
> limits.
>
>>
>> The lower limits you describe are within the OpenGL ES 2 specification and
>> have probably been that way on these iOS devices all along. Many of them are
>> almost certainly fundamental limitations of the hardware.The bright spot is
>> that with the iPhone 6 reportedly selling so well, maybe those older devices
>> won’t be around for much longer.
>
> Most android hardware (which is more budget oriented than iOS hardware)
> already superseeds those well established lower boundaries. It's reasonable
> to assume most iOS hardware in existence does so too (see iPad mini retina,
> and probably everything from iPhone 4 onwards).

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