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    dst_reg sign_recovery_shift;
  34    dst_reg normalize_factor;
  35    dst_reg es3_normalize_factor;
  36
  37    for (int i = 0; i < VERT_ATTRIB_MAX; i++) {
  38       if (vs_prog_data->inputs_read & BITFIELD64_BIT(i)) {
  39          uint8_t wa_flags = key->gl_attrib_wa_flags[i];
  40          dst_reg reg(ATTR, i);
  41          dst_reg reg_d = reg;
  42          reg_d.type = BRW_REGISTER_TYPE_D;
  43          dst_reg reg_ud = reg;
  44          reg_ud.type = BRW_REGISTER_TYPE_UD;
  45
  46          /* Do GL_FIXED rescaling for GLES2.0.  Our GL_FIXED attributes
  47           * come in as floating point conversions of the integer values.
  48           */
  49          if (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK) {
  50             dst_reg dst = reg;
  51             dst.type = brw_type_for_base_type(glsl_type::vec4_type);
  52             dst.writemask = (1 << (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK)) - 1;
  53             emit(MUL(dst, src_reg(dst), brw_imm_f(1.0f / 65536.0f)));
  54          }
  55
  56          /* Do sign recovery for 2101010 formats if required. */
  57          if (wa_flags & BRW_ATTRIB_WA_SIGN) {
  58             if (sign_recovery_shift.file == BAD_FILE) {
  59                /* shift constant: <22,22,22,30> */
  60                sign_recovery_shift = dst_reg(this, glsl_type::uvec4_type);
  61                emit(MOV(writemask(sign_recovery_shift, WRITEMASK_XYZ), brw_imm_ud(22u)));
  62                emit(MOV(writemask(sign_recovery_shift, WRITEMASK_W), brw_imm_ud(30u)));
  63             }
  64
  65             emit(SHL(reg_ud, src_reg(reg_ud), src_reg(sign_recovery_shift)));
  66             emit(ASR(reg_d, src_reg(reg_d), src_reg(sign_recovery_shift)));
  67          }
  68
  69          /* Apply BGRA swizzle if required. */
  70          if (wa_flags & BRW_ATTRIB_WA_BGRA) {
  71             src_reg temp = src_reg(reg);
  72             temp.swizzle = BRW_SWIZZLE4(2,1,0,3);
  73             emit(MOV(reg, temp));
  74          }
  75
  76          if (wa_flags & BRW_ATTRIB_WA_NORMALIZE) {
  77             /* ES 3.0 has different rules for converting signed normalized
  78              * fixed-point numbers than desktop GL.
  79              */
  80             if ((wa_flags & BRW_ATTRIB_WA_SIGN) && !use_legacy_snorm_formula) {
  81                /* According to equation 2.2 of the ES 3.0 specification,
  82                 * signed normalization conversion is done by:
  83                 *
  84                 * f = c / (2^(b-1)-1)
  85                 */
  86                if (es3_normalize_factor.file == BAD_FILE) {
  87                   /* mul constant: 1 / (2^(b-1) - 1) */
  88                   es3_normalize_factor = dst_reg(this, glsl_type::vec4_type);
  89                   emit(MOV(writemask(es3_normalize_factor, WRITEMASK_XYZ),
  90                            brw_imm_f(1.0f / ((1<<9) - 1))));
  91                   emit(MOV(writemask(es3_normalize_factor, WRITEMASK_W),
  92                            brw_imm_f(1.0f / ((1<<1) - 1))));
  93                }
  94
  95                dst_reg dst = reg;
  96                dst.type = brw_type_for_base_type(glsl_type::vec4_type);
  97                emit(MOV(dst, src_reg(reg_d)));
  98                emit(MUL(dst, src_reg(dst), src_reg(es3_normalize_factor)));
  99                emit_minmax(BRW_CONDITIONAL_GE, dst, src_reg(dst), brw_imm_f(-1.0f));
 100             } else {
 101                /* The following equations are from the OpenGL 3.2 specification:
 102                 *
 103                 * 2.1 unsigned normalization
 104                 * f = c/(2^n-1)
 105                 *
 106                 * 2.2 signed normalization
 107                 * f = (2c+1)/(2^n-1)
 108                 *
 109                 * Both of these share a common divisor, which is represented by
 110                 * "normalize_factor" in the code below.
 111                 */
 112                if (normalize_factor.file == BAD_FILE) {
 113                   /* 1 / (2^b - 1) for b=<10,10,10,2> */
 114                   normalize_factor = dst_reg(this, glsl_type::vec4_type);
 115                   emit(MOV(writemask(normalize_factor, WRITEMASK_XYZ),
 116                            brw_imm_f(1.0f / ((1<<10) - 1))));
 117                   emit(MOV(writemask(normalize_factor, WRITEMASK_W),
 118                            brw_imm_f(1.0f / ((1<<2) - 1))));
 119                }
 120
 121                dst_reg dst = reg;
 122                dst.type = brw_type_for_base_type(glsl_type::vec4_type);
 123                emit(MOV(dst, src_reg((wa_flags & BRW_ATTRIB_WA_SIGN) ? reg_d : reg_ud)));
 124
 125                /* For signed normalization, we want the numerator to be 2c+1. */
 126                if (wa_flags & BRW_ATTRIB_WA_SIGN) {
 127                   emit(MUL(dst, src_reg(dst), brw_imm_f(2.0f)));
 128                   emit(ADD(dst, src_reg(dst), brw_imm_f(1.0f)));
 129                }
 130
 131                emit(MUL(dst, src_reg(dst), src_reg(normalize_factor)));
 132             }
 133          }
 134
 135          if (wa_flags & BRW_ATTRIB_WA_SCALE) {
 136             dst_reg dst = reg;
 137             dst.type = brw_type_for_base_type(glsl_type::vec4_type);
 138             emit(MOV(dst, src_reg((wa_flags & BRW_ATTRIB_WA_SIGN) ? reg_d : reg_ud)));
 139          }
 140       }
 141    }
 142 }
 143
 144
 145 dst_reg *
 146 vec4_vs_visitor::make_reg_for_system_value(int location,
 147                                            const glsl_type *type)
 148 {
 149    /* VertexID is stored by the VF as the last vertex element, but
 150     * we don't represent it with a flag in inputs_read, so we call
 151     * it VERT_ATTRIB_MAX, which setup_attributes() picks up on.
 152     */
 153    dst_reg *reg = new(mem_ctx) dst_reg(ATTR, VERT_ATTRIB_MAX);
 154
 155    switch (location) {
 156    case SYSTEM_VALUE_BASE_VERTEX:
 157       reg->writemask = WRITEMASK_X;
 158       vs_prog_data->uses_basevertex = true;
 159       break;
 160    case SYSTEM_VALUE_BASE_INSTANCE:
 161       reg->writemask = WRITEMASK_Y;
 162       vs_prog_data->uses_baseinstance = true;
 163       break;
 164    case SYSTEM_VALUE_VERTEX_ID:
 165    case SYSTEM_VALUE_VERTEX_ID_ZERO_BASE:
 166       reg->writemask = WRITEMASK_Z;
 167       vs_prog_data->uses_vertexid = true;
 168       break;
 169    case SYSTEM_VALUE_INSTANCE_ID:
 170       reg->writemask = WRITEMASK_W;
 171       vs_prog_data->uses_instanceid = true;
 172       break;
 173    default:
 174       unreachable("not reached");
 175    }
 176
 177    return reg;
 178 }
 179
 180
 181 void
 182 vec4_vs_visitor::emit_urb_write_header(int mrf)
 183 {
 184    /* No need to do anything for VS; an implied write to this MRF will be
 185     * performed by VS_OPCODE_URB_WRITE.
 186     */
 187    (void) mrf;
 188 }
 189
 190
 191 vec4_instruction *
 192 vec4_vs_visitor::emit_urb_write_opcode(bool complete)
 193 {
 194    /* For VS, the URB writes end the thread. */
 195    if (complete) {
 196       if (INTEL_DEBUG & DEBUG_SHADER_TIME)
 197          emit_shader_time_end();
 198    }
 199
 200    vec4_instruction *inst = emit(VS_OPCODE_URB_WRITE);
 201    inst->urb_write_flags = complete ?
 202       BRW_URB_WRITE_EOT_COMPLETE : BRW_URB_WRITE_NO_FLAGS;
 203
 204    return inst;
 205 }
 206
 207
 208 void
 209 vec4_vs_visitor::emit_urb_slot(dst_reg reg, int varying)
 210 {
 211    reg.type = BRW_REGISTER_TYPE_F;
 212    output_reg[varying].type = reg.type;
 213
 214    switch (varying) {
 215    case VARYING_SLOT_COL0:
 216    case VARYING_SLOT_COL1:
 217    case VARYING_SLOT_BFC0:
 218    case VARYING_SLOT_BFC1: {
 219       /* These built-in varyings are only supported in compatibility mode,
 220        * and we only support GS in core profile.  So, this must be a vertex
 221        * shader.
 222        */
 223       vec4_instruction *inst = emit_generic_urb_slot(reg, varying);
 224       if (inst && key->clamp_vertex_color)
 225          inst->saturate = true;
 226       break;
 227    }
 228    default:
 229       return vec4_visitor::emit_urb_slot(reg, varying);
 230    }
 231 }
 232
 233
 234 void
 235 vec4_vs_visitor::emit_clip_distances(dst_reg reg, int offset)
 236 {
 237    /* From the GLSL 1.30 spec, section 7.1 (Vertex Shader Special Variables):
 238     *
 239     *     "If a linked set of shaders forming the vertex stage contains no
 240     *     static write to gl_ClipVertex or gl_ClipDistance, but the
 241     *     application has requested clipping against user clip planes through
 242     *     the API, then the coordinate written to gl_Position is used for
 243     *     comparison against the user clip planes."
 244     *
 245     * This function is only called if the shader didn't write to
 246     * gl_ClipDistance.  Accordingly, we use gl_ClipVertex to perform clipping
 247     * if the user wrote to it; otherwise we use gl_Position.
 248     */
 249    gl_varying_slot clip_vertex = VARYING_SLOT_CLIP_VERTEX;
 250    if (!(prog_data->vue_map.slots_valid & VARYING_BIT_CLIP_VERTEX)) {
 251       clip_vertex = VARYING_SLOT_POS;
 252    }
 253
 254    for (int i = 0; i + offset < key->nr_userclip_plane_consts && i < 4;
 255         ++i) {
 256       reg.writemask = 1 << i;
 257       emit(DP4(reg,
 258                src_reg(output_reg[clip_vertex]),
 259                src_reg(this->userplane[i + offset])));
 260    }
 261 }
 262
 263
 264 void
 265 vec4_vs_visitor::setup_uniform_clipplane_values()
 266 {
 267    for (int i = 0; i < key->nr_userclip_plane_consts; ++i) {
 268       assert(this->uniforms < uniform_array_size);
 269       this->userplane[i] = dst_reg(UNIFORM, this->uniforms);
 270       this->userplane[i].type = BRW_REGISTER_TYPE_F;
 271       for (int j = 0; j < 4; ++j) {
 272          stage_prog_data->param[this->uniforms * 4 + j] =
 273             (gl_constant_value *) &clip_planes[i][j];
 274       }
 275       ++this->uniforms;
 276    }
 277 }
 278
 279
 280 void
 281 vec4_vs_visitor::emit_thread_end()
 282 {
 283    setup_uniform_clipplane_values();
 284
 285    /* Lower legacy ff and ClipVertex clipping to clip distances */
 286    if (key->nr_userclip_plane_consts > 0) {
 287       current_annotation = "user clip distances";
 288
 289       output_reg[VARYING_SLOT_CLIP_DIST0] = dst_reg(this, glsl_type::vec4_type);
 290       output_reg[VARYING_SLOT_CLIP_DIST1] = dst_reg(this, glsl_type::vec4_type);
 291
 292       emit_clip_distances(output_reg[VARYING_SLOT_CLIP_DIST0], 0);
 293       emit_clip_distances(output_reg[VARYING_SLOT_CLIP_DIST1], 4);
 294    }
 295
 296    /* For VS, we always end the thread by emitting a single vertex.
 297     * emit_urb_write_opcode() will take care of setting the eot flag on the
 298     * SEND instruction.
 299     */
 300    emit_vertex();
 301 }
 302
 303
 304 vec4_vs_visitor::vec4_vs_visitor(const struct brw_compiler *compiler,
 305                                  void *log_data,
 306                                  const struct brw_vs_prog_key *key,
 307                                  struct brw_vs_prog_data *vs_prog_data,
 308                                  const nir_shader *shader,
 309                                  gl_clip_plane *clip_planes,
 310                                  void *mem_ctx,
 311                                  int shader_time_index,
 312                                  bool use_legacy_snorm_formula)
 313    : vec4_visitor(compiler, log_data, &key->tex, &vs_prog_data->base, shader,
 314                   mem_ctx, false /* no_spills */, shader_time_index),
 315      key(key),
 316      vs_prog_data(vs_prog_data),
 317      clip_planes(clip_planes),
 318      use_legacy_snorm_formula(use_legacy_snorm_formula)
 319 {
 320 }
 321
 322
 323 } /* namespace brw */