wined3d: Bind default sampler object when setting sampler state with no texture.

When sampler state was applied and no stage texture was present in
state, no glBindSampler was issued for the stage after dummy texture was
bound, and previously bound sampler was still active. This could result
in undefined behaviour, especially if previously bound sampler was a
shadow sample (this caused warnings from Nvidia driver).

Signed-off-by: Paul Gofman <gofmanp@gmail.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/wined3d/state.c

@@ -3627,6 +3627,11 @@ static void sampler(struct wined3d_context *context, const struct wined3d_state
     else
     {
         context_bind_texture(context, GL_NONE, 0);
+        if (gl_info->supported[ARB_SAMPLER_OBJECTS])
+        {
+            GL_EXTCALL(glBindSampler(mapped_stage, 0));
+            checkGLcall("glBindSampler");
+        }
     }
 }