Mesa (master): i965/miptree: Layout 1D Array as 2D Array with height of 1

[Jordan Justen]

Module: Mesa
Branch: master
Commit: c860a379d2fa09da1711591b6aef4a885d224ea0
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=c860a379d2fa09da1711591b6aef4a885d224ea0

Author: Jordan Justen <jordan.l.justen at intel.com>
Date:   Thu Jul 31 00:16:19 2014 -0700

i965/miptree: Layout 1D Array as 2D Array with height of 1

1D array miptrees were being laid out as a 2D texture with 1 slice.
This happened due to the mesa core storing the 1D array slice count in
the height field. On Intel hardware, we want to create a 2D array with
a height of 1 for the 1D array case.

Fixes assertion failure in piglit (gen6, gen8):
spec/glsl-1.30/execution/tex-miplevel-selection textureOffset 1DArrayShadow

In release builds of Mesa, this test was observed to cause a GPU hang
on gen8.

Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
Cc: "10.2" <mesa-stable at lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81450
Tested-by: Ben Widawsky <ben at bwidawsk.net>
Reviewed-by: Chris Forbes <chrisf at ijw.co.nz>

---

 src/mesa/drivers/dri/i965/intel_mipmap_tree.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
index b36ffc7..38396d7 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
@@ -243,6 +243,26 @@ intel_miptree_create_layout(struct brw_context *brw,
        _mesa_get_format_name(format),
        first_level, last_level, depth0, mt);
 
+   if (target == GL_TEXTURE_1D_ARRAY) {
+      /* For a 1D Array texture the OpenGL API will treat the height0
+       * parameter as the number of array slices. For Intel hardware, we treat
+       * the 1D array as a 2D Array with a height of 1.
+       *
+       * So, when we first come through this path to create a 1D Array
+       * texture, height0 stores the number of slices, and depth0 is 1. In
+       * this case, we want to swap height0 and depth0.
+       *
+       * Since some miptrees will be created based on the base miptree, we may
+       * come through this path and see height0 as 1 and depth0 being the
+       * number of slices. In this case we don't need to do the swap.
+       */
+      assert(height0 == 1 || depth0 == 1);
+      if (height0 > 1) {
+         depth0 = height0;
+         height0 = 1;
+      }
+   }
+
    mt->target = target;
    mt->format = format;
    mt->first_level = first_level;