i965/gen7: Add R8_UINT stencil miptree copy for sampling

For gen < 8, we can't sample from the stencil buffer, which is
required for the ARB_stencil_texturing extension. We'll make a copy of
the stencil data into a new texture that we can sample using the
R8_UINT surface type.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
index a49da8c..4473126 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
@@ -615,6 +615,18 @@ struct intel_mipmap_tree
    struct intel_mipmap_tree *stencil_mt;
 
    /**
+    * \brief Stencil texturing miptree for sampling from a stencil texture
+    *
+    * Some hardware doesn't support sampling from the stencil texture as
+    * required by the GL_ARB_stencil_texturing extenion. To workaround this we
+    * blit the texture into a new texture that can be sampled.
+    *
+    * \see intel_update_r8stencil()
+    */
+   struct intel_mipmap_tree *r8stencil_mt;
+   bool r8stencil_needs_update;
+
+   /**
     * \brief MCS miptree.
     *
     * This miptree contains the "multisample control surface", which stores