1 /*
2 * Copyright 2023 Valve Corporation
3 * SPDX-License-Identifier: MIT
4 */
5
6 #include "nir.h"
7 #include "nir_builder.h"
8 #include "nir_intrinsics.h"
9 #include "shader_enums.h"
10
11 static bool
lower_tess_coord_z(nir_builder * b,nir_intrinsic_instr * intr,void * state)12 lower_tess_coord_z(nir_builder *b, nir_intrinsic_instr *intr, void *state)
13 {
14 if (intr->intrinsic != nir_intrinsic_load_tess_coord)
15 return false;
16
17 b->cursor = nir_instr_remove(&intr->instr);
18 nir_def *xy = nir_load_tess_coord_xy(b);
19 nir_def *x = nir_channel(b, xy, 0);
20 nir_def *y = nir_channel(b, xy, 1);
21 nir_def *z;
22
23 bool *triangles = state;
24 if (*triangles)
25 z = nir_fsub(b, nir_fsub_imm(b, 1.0f, y), x);
26 else
27 z = nir_imm_float(b, 0.0f);
28
29 nir_def_rewrite_uses(&intr->def, nir_vec3(b, x, y, z));
30 return true;
31 }
32
33 bool
nir_lower_tess_coord_z(nir_shader * shader,bool triangles)34 nir_lower_tess_coord_z(nir_shader *shader, bool triangles)
35 {
36 return nir_shader_intrinsics_pass(shader, lower_tess_coord_z,
37 nir_metadata_control_flow,
38 &triangles);
39 }
40