[Mesa-dev] [PATCH] mesa: fix bad cast conversions in viewport()

[Matt Turner]

On Mon, Jul 31, 2017 at 12:43 PM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> Fixes: ddc32537d6 ("mesa: clamp viewport values only once when using glViewport()")
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101981
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101989
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

I don't understand how this regression happened. I see in the results
of your Jenkins build #57 that
ES3-CTS.functional.state_query.integers.viewport_getfloat fails on all
platforms. Do we need to improve something in the CI?

> ---
>  src/mesa/main/viewport.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/main/viewport.c b/src/mesa/main/viewport.c
> index 3dce320d1d..fc384909e6 100644
> --- a/src/mesa/main/viewport.c
> +++ b/src/mesa/main/viewport.c
> @@ -94,9 +94,10 @@ static void
>  viewport(struct gl_context *ctx, GLint x, GLint y, GLsizei width,
>           GLsizei height)
>  {
> +   struct gl_viewport_inputs input = { x, y, width, height };
> +
>     /* Clamp the viewport to the implementation dependent values. */
> -   clamp_viewport(ctx, (GLfloat *)&x, (GLfloat *)&y,
> -                  (GLfloat *)&width, (GLfloat *)&height);

As an aside, this is violating C's aliasing rules. This pattern isn't
allowed in Mesa since commit 88ad8c7dedb87d92a5bed0868f108076185ec089