src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp

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