1 /*
2 * Copyright © 2019 Collabora Ltd
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24 #include "nir.h"
25 #include "nir_builder.h"
26
27 /** nir_lower_point_size_mov.c
28 *
29 * This pass lowers glPointSize into gl_PointSize, by adding a uniform
30 * and a move from that uniform to VARYING_SLOT_PSIZ. This is useful for
31 * OpenGL ES level hardware that lack constant point-size hardware state.
32 */
33
34 static void
lower_point_size_mov_after(nir_builder * b,nir_variable * in)35 lower_point_size_mov_after(nir_builder *b, nir_variable *in)
36 {
37 nir_def *load = nir_load_var(b, in);
38 load = nir_fclamp(b, nir_channel(b, load, 0), nir_channel(b, load, 1), nir_channel(b, load, 2));
39 if (b->shader->info.io_lowered) {
40 nir_store_output(b, load, nir_imm_int(b, 0),
41 .io_semantics.location = VARYING_SLOT_PSIZ);
42 } else {
43 nir_variable *out = NULL;
44 /* the existing output can't be removed in order to avoid breaking xfb.
45 * drivers must check var->data.explicit_location to find the original output
46 * and only emit that one for xfb
47 */
48 nir_foreach_shader_out_variable(var, b->shader) {
49 if (var->data.location == VARYING_SLOT_PSIZ && !var->data.explicit_location) {
50 out = var;
51 break;
52 }
53 }
54 if (!out) {
55 out = nir_create_variable_with_location(b->shader, nir_var_shader_out,
56 VARYING_SLOT_PSIZ, glsl_float_type());
57 }
58 nir_store_var(b, out, load, 0x1);
59 }
60 }
61
62 static bool
lower_point_size_mov(nir_builder * b,nir_intrinsic_instr * intr,void * data)63 lower_point_size_mov(nir_builder *b, nir_intrinsic_instr *intr, void *data)
64 {
65 nir_variable *var = NULL;
66 switch (intr->intrinsic) {
67 case nir_intrinsic_store_output:
68 case nir_intrinsic_store_per_vertex_output:
69 case nir_intrinsic_store_per_view_output:
70 case nir_intrinsic_store_per_primitive_output: {
71 nir_io_semantics sem = nir_intrinsic_io_semantics(intr);
72 if (sem.location != VARYING_SLOT_PSIZ)
73 return false;
74 break;
75 }
76 case nir_intrinsic_store_deref:
77 var = nir_intrinsic_get_var(intr, 0);
78 if (var->data.location != VARYING_SLOT_PSIZ)
79 return false;
80 break;
81 default:
82 return false;
83 }
84 b->cursor = nir_after_instr(&intr->instr);
85 lower_point_size_mov_after(b, data);
86 if (var && !var->data.explicit_location)
87 nir_instr_remove(&intr->instr);
88 return true;
89 }
90
91 bool
nir_lower_point_size_mov(nir_shader * shader,const gl_state_index16 * pointsize_state_tokens)92 nir_lower_point_size_mov(nir_shader *shader,
93 const gl_state_index16 *pointsize_state_tokens)
94 {
95 assert(shader->info.stage != MESA_SHADER_FRAGMENT &&
96 shader->info.stage != MESA_SHADER_COMPUTE);
97
98
99 bool progress = false;
100 nir_metadata preserved = nir_metadata_control_flow;
101 nir_variable *in = nir_state_variable_create(shader, glsl_vec4_type(),
102 "gl_PointSizeClampedMESA",
103 pointsize_state_tokens);
104 if (shader->info.outputs_written & VARYING_BIT_PSIZ) {
105 progress = nir_shader_intrinsics_pass(shader, lower_point_size_mov, preserved, in);
106 } else {
107 nir_function_impl *impl = nir_shader_get_entrypoint(shader);
108 nir_builder b = nir_builder_at(nir_before_impl(impl));
109
110 lower_point_size_mov_after(&b, in);
111 shader->info.outputs_written |= VARYING_BIT_PSIZ;
112 progress = true;
113 nir_metadata_preserve(impl, preserved);
114 }
115 return progress;
116 }
117