st/mesa: add ARB_texture_stencil8 support (v4)

if we support stencil texturing, enable texture_stencil8
there is no requirement to support native S8 for this,
the texture can be converted to x24s8 fine.

v2: fold fixes from Marek in:
   a) put S8 last in the list
   b) fix renderable to always test for d/s renderable
    fixup the texture case to use a stencil only format
    for picking the format for the texture view.
v3: hit fallback for getteximage
v4: put s8 back in front, it shouldn't get picked now (Ilia)

Reviewed-by: Ilia Mirkin <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>

1 files changed, 10 insertions, 4 deletions

diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
index eff28fc6f37..04ba86448fc 100644
--- a/src/mesa/state_tracker/st_atom_texture.c
+++ b/src/mesa/state_tracker/st_atom_texture.c
@@ -287,16 +287,22 @@ st_get_texture_sampler_view_from_stobj(struct st_context *st,
 				       enum pipe_format format)
 {
    struct pipe_sampler_view **sv;
-
+   const struct st_texture_image *firstImage;
    if (!stObj || !stObj->pt) {
       return NULL;
    }
 
    sv = st_texture_get_sampler_view(st, stObj);
 
-   if (stObj->base.StencilSampling &&
-       util_format_is_depth_and_stencil(format))
-      format = util_format_stencil_only(format);
+   if (util_format_is_depth_and_stencil(format)) {
+      if (stObj->base.StencilSampling)
+         format = util_format_stencil_only(format);
+      else {
+         firstImage = st_texture_image_const(_mesa_base_tex_image(&stObj->base));
+         if (firstImage->base._BaseFormat == GL_STENCIL_INDEX)
+            format = util_format_stencil_only(format);
+      }
+   }
 
    /* if sampler view has changed dereference it */
    if (*sv) {