[Mesa-dev] [PATCH] i965/blorp/gen8: Fix blitting of interleaved msaa surfaces

[Topi Pohjolainen]

Fixes ES31-CTS.gtf.GL31Tests.texture_stencil8.texture_stencil8_multisample.

Current logic divides given layer of one by number of samples (four)
trashing the layer to zero. Layer adjustment is only to be used with
non-interleaved msaa surfaces where samples for particular layer are
in multiple slices.

I copy-pasted a bit of documentation from
brw_blorp.c::brw_blorp_compute_tile_offsets().

Also took the opportunity to fix the comment regarding sampling
as 2D, cube textures are the only exception.

CC: Kenneth Graunke <kenneth at whitecape.org>
Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
---
 src/mesa/drivers/dri/i965/gen8_blorp.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen8_blorp.c b/src/mesa/drivers/dri/i965/gen8_blorp.c
index 43eb4a7..c5aeea4 100644
--- a/src/mesa/drivers/dri/i965/gen8_blorp.c
+++ b/src/mesa/drivers/dri/i965/gen8_blorp.c
@@ -601,14 +601,28 @@ gen8_blorp_emit_surface_states(struct brw_context *brw,
       const struct brw_blorp_surface_info *surface = &params->src;
       struct intel_mipmap_tree *mt = surface->mt;
 
-      /* Textures are always sampled as 2D. */
+      /* If src is a 2D multisample array texture on Gen7+ using
+       * INTEL_MSAA_LAYOUT_UMS or INTEL_MSAA_LAYOUT_CMS, src layer is the
+       * physical layer holding sample 0.  So, for example, if mt->num_samples
+       * == 4, then logical layer n corresponds to layer == 4*n.
+       *
+       * Multisampled depth and stencil surfaces have the samples interleaved
+       * (INTEL_MSAA_LAYOUT_IMS) and therefore the layer doesn't need
+       * adjustment.
+       */
+      const unsigned layer_divider =
+         (mt->msaa_layout == INTEL_MSAA_LAYOUT_UMS ||
+          mt->msaa_layout == INTEL_MSAA_LAYOUT_CMS) ?
+         MAX2(mt->num_samples, 1) : 1;
+
+      /* Cube textures are sampled as 2D array. */
       const bool is_cube = mt->target == GL_TEXTURE_CUBE_MAP_ARRAY ||
                            mt->target == GL_TEXTURE_CUBE_MAP;
       const unsigned depth = (is_cube ? 6 : 1) * mt->logical_depth0;
       const GLenum target = is_cube ? GL_TEXTURE_2D_ARRAY : mt->target;
       const unsigned max_level = surface->level + mt->last_level + 1;
       const unsigned layer = mt->target != GL_TEXTURE_3D ?
-                                surface->layer / MAX2(mt->num_samples, 1) : 0;
+                                surface->layer / layer_divider : 0;
 
       brw->vtbl.emit_texture_surface_state(brw, mt, target,
                                            layer, layer + depth,
-- 
2.5.5