pan/mdg: Implement gl_SampleID

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5929>

diff --git a/src/panfrost/midgard/midgard_compile.c b/src/panfrost/midgard/midgard_compile.c
index d8780dfd60b858a732fccd5cff5778a51e1c2fd8..fa9ff9eb07fa0e2853784dd28d84370eb5306d4c 100644 (file)
--- a/src/panfrost/midgard/midgard_compile.c
+++ b/src/panfrost/midgard/midgard_compile.c
@@ -1635,6 +1635,22 @@ emit_vertex_builtin(compiler_context *ctx, nir_intrinsic_instr *instr)
         emit_attr_read(ctx, reg, vertex_builtin_arg(instr->intrinsic), 1, nir_type_int);
 }
 
+static void
+emit_msaa_builtin(compiler_context *ctx, nir_intrinsic_instr *instr)
+{
+        unsigned reg = nir_dest_index(&instr->dest);
+
+        midgard_instruction ld = m_ld_color_buffer_32u(reg, 0);
+        ld.load_store.op = midgard_op_ld_color_buffer_32u_old;
+        ld.load_store.address = 97;
+        ld.load_store.arg_2 = 0x1E;
+
+        for (int i = 0; i < 4; ++i)
+                ld.swizzle[0][i] = COMPONENT_X;
+
+        emit_mir_instruction(ctx, ld);
+}
+
 static void
 emit_control_barrier(compiler_context *ctx)
 {
@@ -2015,6 +2031,10 @@ emit_intrinsic(compiler_context *ctx, nir_intrinsic_instr *instr)
                 emit_vertex_builtin(ctx, instr);
                 break;
 
+        case nir_intrinsic_load_sample_id:
+                emit_msaa_builtin(ctx, instr);
+                break;
+
         case nir_intrinsic_memory_barrier_buffer:
         case nir_intrinsic_memory_barrier_shared:
                 break;