1 /*
2 * Copyright © 2013 Intel Corporation
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
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24
25 #include "brw_vs.h"
26
27
28 namespace brw {
29
30 void
emit_prolog()31 vec4_vs_visitor::emit_prolog()
32 {
33 }
34
35
36 dst_reg *
make_reg_for_system_value(int location)37 vec4_vs_visitor::make_reg_for_system_value(int location)
38 {
39 /* VertexID is stored by the VF as the last vertex element, but
40 * we don't represent it with a flag in inputs_read, so we call
41 * it VERT_ATTRIB_MAX, which setup_attributes() picks up on.
42 */
43 dst_reg *reg = new(mem_ctx) dst_reg(ATTR, VERT_ATTRIB_MAX);
44
45 switch (location) {
46 case SYSTEM_VALUE_BASE_VERTEX:
47 reg->writemask = WRITEMASK_X;
48 vs_prog_data->uses_basevertex = true;
49 break;
50 case SYSTEM_VALUE_BASE_INSTANCE:
51 reg->writemask = WRITEMASK_Y;
52 vs_prog_data->uses_baseinstance = true;
53 break;
54 case SYSTEM_VALUE_VERTEX_ID:
55 case SYSTEM_VALUE_VERTEX_ID_ZERO_BASE:
56 reg->writemask = WRITEMASK_Z;
57 vs_prog_data->uses_vertexid = true;
58 break;
59 case SYSTEM_VALUE_INSTANCE_ID:
60 reg->writemask = WRITEMASK_W;
61 vs_prog_data->uses_instanceid = true;
62 break;
63 case SYSTEM_VALUE_DRAW_ID:
64 reg = new(mem_ctx) dst_reg(ATTR, VERT_ATTRIB_MAX + 1);
65 reg->writemask = WRITEMASK_X;
66 vs_prog_data->uses_drawid = true;
67 break;
68 default:
69 unreachable("not reached");
70 }
71
72 return reg;
73 }
74
75
76 void
emit_urb_write_header(int mrf)77 vec4_vs_visitor::emit_urb_write_header(int mrf)
78 {
79 /* No need to do anything for VS; an implied write to this MRF will be
80 * performed by VS_OPCODE_URB_WRITE.
81 */
82 (void) mrf;
83 }
84
85
86 vec4_instruction *
emit_urb_write_opcode(bool complete)87 vec4_vs_visitor::emit_urb_write_opcode(bool complete)
88 {
89 /* For VS, the URB writes end the thread. */
90 if (complete) {
91 if (INTEL_DEBUG & DEBUG_SHADER_TIME)
92 emit_shader_time_end();
93 }
94
95 vec4_instruction *inst = emit(VS_OPCODE_URB_WRITE);
96 inst->urb_write_flags = complete ?
97 BRW_URB_WRITE_EOT_COMPLETE : BRW_URB_WRITE_NO_FLAGS;
98
99 return inst;
100 }
101
102
103 void
emit_urb_slot(dst_reg reg,int varying)104 vec4_vs_visitor::emit_urb_slot(dst_reg reg, int varying)
105 {
106 reg.type = BRW_REGISTER_TYPE_F;
107 output_reg[varying][0].type = reg.type;
108
109 switch (varying) {
110 case VARYING_SLOT_COL0:
111 case VARYING_SLOT_COL1:
112 case VARYING_SLOT_BFC0:
113 case VARYING_SLOT_BFC1: {
114 /* These built-in varyings are only supported in compatibility mode,
115 * and we only support GS in core profile. So, this must be a vertex
116 * shader.
117 */
118 vec4_instruction *inst = emit_generic_urb_slot(reg, varying, 0);
119 if (inst && key->clamp_vertex_color)
120 inst->saturate = true;
121 break;
122 }
123 default:
124 return vec4_visitor::emit_urb_slot(reg, varying);
125 }
126 }
127
128
129 void
emit_clip_distances(dst_reg reg,int offset)130 vec4_vs_visitor::emit_clip_distances(dst_reg reg, int offset)
131 {
132 /* From the GLSL 1.30 spec, section 7.1 (Vertex Shader Special Variables):
133 *
134 * "If a linked set of shaders forming the vertex stage contains no
135 * static write to gl_ClipVertex or gl_ClipDistance, but the
136 * application has requested clipping against user clip planes through
137 * the API, then the coordinate written to gl_Position is used for
138 * comparison against the user clip planes."
139 *
140 * This function is only called if the shader didn't write to
141 * gl_ClipDistance. Accordingly, we use gl_ClipVertex to perform clipping
142 * if the user wrote to it; otherwise we use gl_Position.
143 */
144 gl_varying_slot clip_vertex = VARYING_SLOT_CLIP_VERTEX;
145 if (!(prog_data->vue_map.slots_valid & VARYING_BIT_CLIP_VERTEX)) {
146 clip_vertex = VARYING_SLOT_POS;
147 }
148
149 for (int i = 0; i + offset < key->nr_userclip_plane_consts && i < 4;
150 ++i) {
151 reg.writemask = 1 << i;
152 emit(DP4(reg,
153 src_reg(output_reg[clip_vertex][0]),
154 src_reg(this->userplane[i + offset])));
155 }
156 }
157
158
159 void
setup_uniform_clipplane_values()160 vec4_vs_visitor::setup_uniform_clipplane_values()
161 {
162 for (int i = 0; i < key->nr_userclip_plane_consts; ++i) {
163 this->userplane[i] = dst_reg(UNIFORM, this->uniforms);
164 this->userplane[i].type = BRW_REGISTER_TYPE_F;
165 for (int j = 0; j < 4; ++j) {
166 stage_prog_data->param[this->uniforms * 4 + j] =
167 (gl_constant_value *) &clip_planes[i][j];
168 }
169 ++this->uniforms;
170 }
171 }
172
173
174 void
emit_thread_end()175 vec4_vs_visitor::emit_thread_end()
176 {
177 setup_uniform_clipplane_values();
178
179 /* Lower legacy ff and ClipVertex clipping to clip distances */
180 if (key->nr_userclip_plane_consts > 0) {
181 current_annotation = "user clip distances";
182
183 output_reg[VARYING_SLOT_CLIP_DIST0][0] =
184 dst_reg(this, glsl_type::vec4_type);
185 output_reg[VARYING_SLOT_CLIP_DIST1][0] =
186 dst_reg(this, glsl_type::vec4_type);
187 output_num_components[VARYING_SLOT_CLIP_DIST0][0] = 4;
188 output_num_components[VARYING_SLOT_CLIP_DIST1][0] = 4;
189
190 emit_clip_distances(output_reg[VARYING_SLOT_CLIP_DIST0][0], 0);
191 emit_clip_distances(output_reg[VARYING_SLOT_CLIP_DIST1][0], 4);
192 }
193
194 /* For VS, we always end the thread by emitting a single vertex.
195 * emit_urb_write_opcode() will take care of setting the eot flag on the
196 * SEND instruction.
197 */
198 emit_vertex();
199 }
200
201
vec4_vs_visitor(const struct brw_compiler * compiler,void * log_data,const struct brw_vs_prog_key * key,struct brw_vs_prog_data * vs_prog_data,const nir_shader * shader,gl_clip_plane * clip_planes,void * mem_ctx,int shader_time_index,bool use_legacy_snorm_formula)202 vec4_vs_visitor::vec4_vs_visitor(const struct brw_compiler *compiler,
203 void *log_data,
204 const struct brw_vs_prog_key *key,
205 struct brw_vs_prog_data *vs_prog_data,
206 const nir_shader *shader,
207 gl_clip_plane *clip_planes,
208 void *mem_ctx,
209 int shader_time_index,
210 bool use_legacy_snorm_formula)
211 : vec4_visitor(compiler, log_data, &key->tex, &vs_prog_data->base, shader,
212 mem_ctx, false /* no_spills */, shader_time_index),
213 key(key),
214 vs_prog_data(vs_prog_data),
215 clip_planes(clip_planes),
216 use_legacy_snorm_formula(use_legacy_snorm_formula)
217 {
218 }
219
220
221 } /* namespace brw */
222