Stephen White 17601930e4 GLSL: fix textureSampleLevel() on depth textures. ...

Multiple bugs here:

1) Like texture(), GLSL's textureLod() on depth textures returns a
   scalar, and does not need to be swizzled. So set glsl_ret_width to
   1 in that case.
2) Like texture(), GLSL's textureLod() always requires a Dref
   parameter, so append a zero if not present.
3) GLSL's "lod" parameter to textureLod() is always a float, unlike
   WGSL's textureSampleLevel() which is an i32 for depth textures,
   so cast it.

Along the way, I discovered that textureLod() is not supported on
samplerCubeShadow or sampler2DArrayShadow (even on Desktop GL). So some
tests will never pass. Logged as https://crbug.com/dawn/1313

Bug: tint:1456
Change-Id: If67d8d288704142278d7a4e52b46e8010776f381
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/82300
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>

2022-03-02 14:01:00 +00:00

..

tint

GLSL: fix textureSampleLevel() on depth textures.

2022-03-02 14:01:00 +00:00