[Mesa-dev] [PATCH] mesa/main/readpix: Correct handling of packed floating point values

[Gurchetan Singh]

For those wondering why the dEQP CTS tests this fixes (for example
dEQP-GLES3.functional.fragment_out.basic.float.r11f_g11f_b10f_lowp_float)
pass outside the VM, it seems it's because the test cases read pixels
with type = GL_FLOAT.  virglrenderer always sets type =
GL_UNSIGNED_INT_10F_11F_11F_REV on the host when reading back
GL_R11F_G11F_B10F and probably converts to GL_FLOAT on the guest.  I
guess nobody, even conformance suites, wanted to deal with
GL_UNSIGNED_INT_10F_11F_11F_REV ...

Reviewed-by: Gurchetan Singh <gurchetansingh at chromium.org>
(don't have commit access so hopefully someone merges this)

On Fri, Apr 27, 2018 at 9:04 AM, Gert Wollny <gw.fossdev at gmail.com> wrote:
> From: Gert Wollny <gert.wollny at collabora.com>
>
> Make sure that clamping in the pixel transfer operations is enabled/disabled
> for packed floating point values just like it is done for single normal and
> half precision floating point values.
>
> This fixes a series of CTS tests with virgl that use r11f_g11f_b10f
> buffers as target, and where virglrenderer reads these surfaces back
> using the format GL_UNSIGNED_INT_10F_11F_11F_REV.
>
> Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
> ---
> PS: I don't have write permissions to mesa git
>
>  src/mesa/main/readpix.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
> index a4eea3043d..c5fc66988b 100644
> --- a/src/mesa/main/readpix.c
> +++ b/src/mesa/main/readpix.c
> @@ -106,7 +106,8 @@ _mesa_get_readpixels_transfer_ops(const struct gl_context *ctx,
>        /* For blit-based ReadPixels packing, the clamping is done automatically
>         * unless the type is float. */
>        if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) &&
> -          (type == GL_FLOAT || type == GL_HALF_FLOAT)) {
> +          (type == GL_FLOAT || type == GL_HALF_FLOAT ||
> +           type == GL_UNSIGNED_INT_10F_11F_11F_REV)) {
>           transferOps |= IMAGE_CLAMP_BIT;
>        }
>     }
> @@ -114,7 +115,8 @@ _mesa_get_readpixels_transfer_ops(const struct gl_context *ctx,
>        /* For CPU-based ReadPixels packing, the clamping must always be done
>         * for non-float types, */
>        if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) ||
> -          (type != GL_FLOAT && type != GL_HALF_FLOAT)) {
> +          (type != GL_FLOAT && type != GL_HALF_FLOAT &&
> +           type != GL_UNSIGNED_INT_10F_11F_11F_REV)) {
>           transferOps |= IMAGE_CLAMP_BIT;
>        }
>     }
> --
> 2.17.0
>
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