gallivm: add sample id/pos intrinsic support

The sample position is looked up in an incoming array using the
sample id.

(These are mostly for ARB_sample_shading support)

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4122>

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir.c b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
index 1b1d700..4944b0f 100644 (file)
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
@@ -1340,6 +1340,8 @@ static void visit_intrinsic(struct lp_build_nir_context *bld_base,
    case nir_intrinsic_load_tess_level_outer:
    case nir_intrinsic_load_tess_level_inner:
    case nir_intrinsic_load_patch_vertices_in:
+   case nir_intrinsic_load_sample_id:
+   case nir_intrinsic_load_sample_pos:
       bld_base->sysval_intrin(bld_base, instr, result);
       break;
    case nir_intrinsic_load_helper_invocation:

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
index e5bc1c7..3ae3323 100644 (file)
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
@@ -1375,6 +1375,17 @@ static void emit_sysval_intrin(struct lp_build_nir_context *bld_base,
    case nir_intrinsic_load_patch_vertices_in:
       result[0] = bld->system_values.vertices_in;
       break;
+   case nir_intrinsic_load_sample_id:
+      result[0] = lp_build_broadcast_scalar(&bld_base->uint_bld, bld->system_values.sample_id);
+      break;
+   case nir_intrinsic_load_sample_pos:
+      for (unsigned i = 0; i < 2; i++) {
+         LLVMValueRef idx = LLVMBuildMul(gallivm->builder, bld->system_values.sample_id, lp_build_const_int32(gallivm, 2), "");
+         idx = LLVMBuildAdd(gallivm->builder, idx, lp_build_const_int32(gallivm, i), "");
+         LLVMValueRef val = LLVMBuildGEP(gallivm->builder, bld->system_values.sample_pos, &idx, 1, "");
+         result[i] = lp_build_broadcast_scalar(&bld_base->base, LLVMBuildLoad(gallivm->builder, val, ""));
+      }
+      break;
    }
 }
 

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h b/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
index 6af8b0b..a543e2e 100644 (file)
--- a/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
@@ -183,6 +183,8 @@ struct lp_bld_tgsi_system_values {
    LLVMValueRef tess_outer;
    LLVMValueRef tess_inner;
    LLVMValueRef vertices_in;
+   LLVMValueRef sample_id;
+   LLVMValueRef sample_pos;
 };