intel/nir/rt: fix reportIntersection() hitT handling

We're currently updating the hitT value in the traversal result with
the hitT value from reportIntersection(), but this is not correct.

First the hitT value of reportIntersection() should update the
gl_RayTmaxEXT value (maps to brw_nir_rt_mem_ray_defs::t_far).

Second the hitT determined by traversal should only be updated if the
reportIntersection() hitT value has updated the gl_RayTmaxEXT and that
the new gl_RayTmaxEXT is smaller than the determined hitT value from
traversal.

Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Fixes: 303378e1dd ("intel/rt: Add lowering for combined intersection/any-hit shaders")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25146>
(cherry picked from commit 4eb4197d27aed6f5e71195a971145b2945d78330)

diff --git a/.pick_status.json b/.pick_status.json
index d53c5e1..02852cb 100644 (file)
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -1054,7 +1054,7 @@
         "description": "intel/nir/rt: fix reportIntersection() hitT handling",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "303378e1dd4119e04e0f6cb623766115a00c2eea",
         "notes": null

diff --git a/src/intel/compiler/brw_nir_lower_intersection_shader.c b/src/intel/compiler/brw_nir_lower_intersection_shader.c
index 90e2f03..b26339b 100644 (file)
--- a/src/intel/compiler/brw_nir_lower_intersection_shader.c
+++ b/src/intel/compiler/brw_nir_lower_intersection_shader.c
@@ -196,7 +196,14 @@ brw_nir_lower_intersection_shader(nir_shader *intersection,
                nir_def *hit_t = intrin->src[0].ssa;
                nir_def *hit_kind = intrin->src[1].ssa;
                nir_def *min_t = nir_load_ray_t_min(b);
-               nir_def *max_t = nir_load_global(b, t_addr, 4, 1, 32);
+
+               struct brw_nir_rt_mem_ray_defs ray_def;
+               brw_nir_rt_load_mem_ray(b, &ray_def, BRW_RT_BVH_LEVEL_WORLD);
+
+               struct brw_nir_rt_mem_hit_defs hit_in = {};
+               brw_nir_rt_load_mem_hit(b, &hit_in, false);
+
+               nir_def *max_t = ray_def.t_far;
 
                /* bool commit_tmp = false; */
                nir_variable *commit_tmp =
@@ -227,8 +234,13 @@ brw_nir_lower_intersection_shader(nir_shader *intersection,
                   nir_push_if(b, nir_load_var(b, commit_tmp));
                   {
                      nir_store_var(b, commit, nir_imm_true(b), 0x1);
+
+                     nir_def *ray_addr =
+                        brw_nir_rt_mem_ray_addr(b, brw_nir_rt_stack_addr(b), BRW_RT_BVH_LEVEL_WORLD);
+
+                     nir_store_global(b, nir_iadd_imm(b, ray_addr, 16 + 12), 4,  hit_t, 0x1);
                      nir_store_global(b, t_addr, 4,
-                                      nir_vec2(b, hit_t, hit_kind),
+                                      nir_vec2(b, nir_fmin(b, hit_t, hit_in.t), hit_kind),
                                       0x3);
                   }
                   nir_pop_if(b, NULL);