On Wed, Jun 5, 2013 at 11:07 PM, Benoit
Jacob <bjacob@mozilla.com>
wrote:
So, we are about to implement this now in Mozilla. Just a
question: in
the current specification, when linear filtering is used
without
OES_texture_float_linear enabled, should the outcome be
RGBA=(0,0,0,0)
texel values as in the case of an incomplete texture?
Benoit
On 13-05-28 06:21 PM, Gregg Tavares wrote:
> There's was a bug in both Chrome and Firefox which
is that the
> OES_texture_float extension should not have allowed
linear filtering.
> That bug has been fixed in Chrome Canary.
>
> To use floating point textures with linear
filtering you must get both
> the OES_texture_float and OES_texture_float_linear
extensions.
>
> I suspect this will break the majority of WebGL
apps that use floating
> point textures. Fortunately there are not 'that'
many and the fix is easy.
>
> For most of the existing WebGL apps using floating
point textures you
> need to do this to get the behavior you were
getting previously.
>
> ext1 = gl.getExtension("OES_texture_float");
> ext2 =
gl.getExtension("OES_texture_float_linear");
>
> Otherwise if OES_texture_float_linear does not
exist you can set your
> filtering to NEAREST something like
>
> ext1 = gl.getExtension("OES_texture_float");
> if (!ext1) {
> alert("no support for floating point
textures");
> return;
> }
> ext2 =
gl.getExtension("OES_texture_float_linear");
> float_filtering = ext2 ? gl.LINEAR : gl.NEAREST;
>
> ... when using floating point textures
>
> gl.texImage2D(,....., gl.FLOAT, ..);
> gl.texParameter(...., gl.TEXTURE_MIN_FILTER,
float_filtering);
> gl.texParameter(...., gl.TEXTURE_MAG_FILTER,
float_filtering);
>
>
> Note: While it's sad this fix broke some apps the
apps were already
> broken as many mobile GPUs support
OES_texture_float but not
> OES_texture_float_linear. This fix makes it
possible for an app to
> tell if a device supports OES_texture_float_linear
and take
> appropriate steps.
>
>
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