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Re: [Public WebGL] color buffer (half) float



On 24/06/2014 02:51, Kenneth Russell wrote:


        
Yes. There is a significant technical issue with implementing
WEBGL_color_buffer_float on top of OpenGL ES 2.0, which is that there
is no ES 2.0 extension defining the behavior of color_buffer_float.
There was an attempt to implement EXT_color_buffer_half_float and
WEBGL_color_buffer_float both in ANGLE and Chrome a few months ago and
the code was simply incorrect. Adding these extensions to WebGL 2.0
will be trivial because it's based on OpenGL ES 3.0, on top of which
the underlying extensions are defined. I think that all WebGL
implementers' time should be invested in WebGL 2.0 specification,
conformance suite, and implementation work at this point, not adding
more extensions to WebGL 1.0 implementations.
While I do not object to Florian's proposal to move these extension specs to abandoned and to concentrate on WebGL 2.0, I feel a need to point out a few issues in the above statements.

While there is no ES 2.0 extension, WEBGL_color_buffer_float defines the required behavior for float32 as precisely as OES_color_buffer_half_float does for float16. I see no technical issue. The lack of an ES extension merely means that you would never advertise WEBGL_color_buffer_float when running atop ES 2.0. You would only advertise it when running atop desktop.

One of the failed/abandoned patches Ken pointed at in his later mail refers to issues with ANGLE and DX11 supporting only R32F and RG32F. That issue is going to have to be dealt with for WebGL 2.0 implementations on ANGLE. It is not cured because OES_color_buffer_float exists for ES 3.x. In fact it might be worse because the OES extension requires a bunch of sized internal formats to be color-renderable not just an unsized format.

BTW, when you all implement WebGL 2.0 please ensure that linear filtering of float32 textures is NOT accidentally enabled when running atop desktop.

Regards

    -Mark

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