i965/vec4: Support arbitrarily large sampler state indices on Haswell+.

Like the scalar backend, we add an offset to the "Sampler State Pointer"
field to select a group of 16 samplers, then use the "Sampler Index"
field to select within that group.

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Matt Turner <[email protected]>
Reviewed-by: Chris Forbes <[email protected]>

1 files changed, 8 insertions, 2 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index daf46b6ab82..8c287c244b5 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -2370,9 +2370,15 @@ vec4_visitor::visit(ir_texture *ir)
    if (ir->op == ir_tg4)
       inst->texture_offset |= gather_channel(ir, sampler) << 16;
 
-   /* Texel offsets go in the message header; Gen4 also requires headers. */
+   /* The message header is necessary for:
+    * - Gen4 (always)
+    * - Texel offsets
+    * - Gather channel selection
+    * - Sampler indices too large to fit in a 4-bit value.
+    */
    inst->header_present =
-      brw->gen < 5 || inst->texture_offset != 0 || ir->op == ir_tg4;
+      brw->gen < 5 || inst->texture_offset != 0 || ir->op == ir_tg4 ||
+      sampler >= 16;
    inst->base_mrf = 2;
    inst->mlen = inst->header_present + 1; /* always at least one */
    inst->sampler = sampler;