src/mesa/drivers/dri/i965/gen6_sf_state.c

   1 /*
   2  * Copyright © 2009 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 DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 #include "brw_context.h"
  29 #include "brw_state.h"
  30 #include "brw_defines.h"
  31 #include "brw_util.h"
  32 #include "main/macros.h"
  33 #include "main/fbobject.h"
  34 #include "main/framebuffer.h"
  35 #include "intel_batchbuffer.h"
  36
  37 /**
  38  * Determine the appropriate attribute override value to store into the
  39  * 3DSTATE_SF structure for a given fragment shader attribute.  The attribute
  40  * override value contains two pieces of information: the location of the
  41  * attribute in the VUE (relative to urb_entry_read_offset, see below), and a
  42  * flag indicating whether to "swizzle" the attribute based on the direction
  43  * the triangle is facing.
  44  *
  45  * If an attribute is "swizzled", then the given VUE location is used for
  46  * front-facing triangles, and the VUE location that immediately follows is
  47  * used for back-facing triangles.  We use this to implement the mapping from
  48  * gl_FrontColor/gl_BackColor to gl_Color.
  49  *
  50  * urb_entry_read_offset is the offset into the VUE at which the SF unit is
  51  * being instructed to begin reading attribute data.  It can be set to a
  52  * nonzero value to prevent the SF unit from wasting time reading elements of
  53  * the VUE that are not needed by the fragment shader.  It is measured in
  54  * 256-bit increments.
  55  */
  56 static uint32_t
  57 get_attr_override(const struct brw_vue_map *vue_map, int urb_entry_read_offset,
  58                   int fs_attr, bool two_side_color, uint32_t *max_source_attr)
  59 {
  60    /* Find the VUE slot for this attribute. */
  61    int slot = vue_map->varying_to_slot[fs_attr];
  62
  63    /* Viewport and Layer are stored in the VUE header.  We need to override
  64     * them to zero if earlier stages didn't write them, as GL requires that
  65     * they read back as zero when not explicitly set.
  66     */
  67    if (fs_attr == VARYING_SLOT_VIEWPORT || fs_attr == VARYING_SLOT_LAYER) {
  68       unsigned override =
  69          ATTRIBUTE_0_OVERRIDE_X | ATTRIBUTE_0_OVERRIDE_W |
  70          ATTRIBUTE_CONST_0000 << ATTRIBUTE_0_CONST_SOURCE_SHIFT;
  71
  72       if (!(vue_map->slots_valid & VARYING_BIT_LAYER))
  73          override |= ATTRIBUTE_0_OVERRIDE_Y;
  74       if (!(vue_map->slots_valid & VARYING_BIT_VIEWPORT))
  75          override |= ATTRIBUTE_0_OVERRIDE_Z;
  76
  77       return override;
  78    }
  79
  80    /* If there was only a back color written but not front, use back
  81     * as the color instead of undefined
  82     */
  83    if (slot == -1 && fs_attr == VARYING_SLOT_COL0)
  84       slot = vue_map->varying_to_slot[VARYING_SLOT_BFC0];
  85    if (slot == -1 && fs_attr == VARYING_SLOT_COL1)
  86       slot = vue_map->varying_to_slot[VARYING_SLOT_BFC1];
  87
  88    if (slot == -1) {
  89       /* This attribute does not exist in the VUE--that means that the vertex
  90        * shader did not write to it.  This means that either:
  91        *
  92        * (a) This attribute is a texture coordinate, and it is going to be
  93        * replaced with point coordinates (as a consequence of a call to
  94        * glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE)), so the
  95        * hardware will ignore whatever attribute override we supply.
  96        *
  97        * (b) This attribute is read by the fragment shader but not written by
  98        * the vertex shader, so its value is undefined.  Therefore the
  99        * attribute override we supply doesn't matter.
 100        *
 101        * (c) This attribute is gl_PrimitiveID, and it wasn't written by the
 102        * previous shader stage.
 103        *
 104        * Note that we don't have to worry about the cases where the attribute
 105        * is gl_PointCoord or is undergoing point sprite coordinate
 106        * replacement, because in those cases, this function isn't called.
 107        *
 108        * In case (c), we need to program the attribute overrides so that the
 109        * primitive ID will be stored in this slot.  In every other case, the
 110        * attribute override we supply doesn't matter.  So just go ahead and
 111        * program primitive ID in every case.
 112        */
 113       return (ATTRIBUTE_0_OVERRIDE_W |
 114               ATTRIBUTE_0_OVERRIDE_Z |
 115               ATTRIBUTE_0_OVERRIDE_Y |
 116               ATTRIBUTE_0_OVERRIDE_X |
 117               (ATTRIBUTE_CONST_PRIM_ID << ATTRIBUTE_0_CONST_SOURCE_SHIFT));
 118    }
 119
 120    /* Compute the location of the attribute relative to urb_entry_read_offset.
 121     * Each increment of urb_entry_read_offset represents a 256-bit value, so
 122     * it counts for two 128-bit VUE slots.
 123     */
 124    int source_attr = slot - 2 * urb_entry_read_offset;
 125    assert(source_attr >= 0 && source_attr < 32);
 126
 127    /* If we are doing two-sided color, and the VUE slot following this one
 128     * represents a back-facing color, then we need to instruct the SF unit to
 129     * do back-facing swizzling.
 130     */
 131    bool swizzling = two_side_color &&
 132       ((vue_map->slot_to_varying[slot] == VARYING_SLOT_COL0 &&
 133         vue_map->slot_to_varying[slot+1] == VARYING_SLOT_BFC0) ||
 134        (vue_map->slot_to_varying[slot] == VARYING_SLOT_COL1 &&
 135         vue_map->slot_to_varying[slot+1] == VARYING_SLOT_BFC1));
 136
 137    /* Update max_source_attr.  If swizzling, the SF will read this slot + 1. */
 138    if (*max_source_attr < source_attr + swizzling)
 139       *max_source_attr = source_attr + swizzling;
 140
 141    if (swizzling) {
 142       return source_attr |
 143          (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 144    }
 145
 146    return source_attr;
 147 }
 148
 149
 150 static bool
 151 is_drawing_points(const struct brw_context *brw)
 152 {
 153    /* Determine if the primitives *reaching the SF* are points */
 154    /* _NEW_POLYGON */
 155    if (brw->ctx.Polygon.FrontMode == GL_POINT ||
 156        brw->ctx.Polygon.BackMode == GL_POINT) {
 157       return true;
 158    }
 159
 160    if (brw->geometry_program) {
 161       /* BRW_NEW_GEOMETRY_PROGRAM */
 162       return brw->geometry_program->OutputType == GL_POINTS;
 163    } else {
 164       /* BRW_NEW_PRIMITIVE */
 165       return brw->primitive == _3DPRIM_POINTLIST;
 166    }
 167 }
 168
 169
 170 /**
 171  * Create the mapping from the FS inputs we produce to the previous pipeline
 172  * stage (GS or VS) outputs they source from.
 173  */
 174 void
 175 calculate_attr_overrides(const struct brw_context *brw,
 176                          uint16_t *attr_overrides,
 177                          uint32_t *point_sprite_enables,
 178                          uint32_t *flat_enables,
 179                          uint32_t *urb_entry_read_length,
 180                          uint32_t *urb_entry_read_offset)
 181 {
 182    uint32_t max_source_attr = 0;
 183
 184    *point_sprite_enables = 0;
 185    *flat_enables = 0;
 186
 187    *urb_entry_read_offset = BRW_SF_URB_ENTRY_READ_OFFSET;
 188
 189    /* BRW_NEW_FRAGMENT_PROGRAM
 190     *
 191     * If the fragment shader reads VARYING_SLOT_LAYER, then we need to pass in
 192     * the full vertex header.  Otherwise, we can program the SF to start
 193     * reading at an offset of 1 (2 varying slots) to skip unnecessary data:
 194     * - VARYING_SLOT_PSIZ and BRW_VARYING_SLOT_NDC on gen4-5
 195     * - VARYING_SLOT_{PSIZ,LAYER} and VARYING_SLOT_POS on gen6+
 196     */
 197
 198    bool fs_needs_vue_header = brw->fragment_program->Base.InputsRead &
 199       (VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT);
 200
 201    *urb_entry_read_offset = fs_needs_vue_header ? 0 : 1;
 202
 203    /* _NEW_LIGHT */
 204    bool shade_model_flat = brw->ctx.Light.ShadeModel == GL_FLAT;
 205
 206    /* From the Ivybridge PRM, Vol 2 Part 1, 3DSTATE_SBE,
 207     * description of dw10 Point Sprite Texture Coordinate Enable:
 208     *
 209     * "This field must be programmed to zero when non-point primitives
 210     * are rendered."
 211     *
 212     * The SandyBridge PRM doesn't explicitly say that point sprite enables
 213     * must be programmed to zero when rendering non-point primitives, but
 214     * the IvyBridge PRM does, and if we don't, we get garbage.
 215     *
 216     * This is not required on Haswell, as the hardware ignores this state
 217     * when drawing non-points -- although we do still need to be careful to
 218     * correctly set the attr overrides.
 219     */
 220    /* BRW_NEW_PRIMITIVE | BRW_NEW_GEOMETRY_PROGRAM */
 221    bool drawing_points = is_drawing_points(brw);
 222
 223    /* Initialize all the attr_overrides to 0.  In the loop below we'll modify
 224     * just the ones that correspond to inputs used by the fs.
 225     */
 226    memset(attr_overrides, 0, 16*sizeof(*attr_overrides));
 227
 228    for (int attr = 0; attr < VARYING_SLOT_MAX; attr++) {
 229       /* BRW_NEW_FRAGMENT_PROGRAM */
 230       enum glsl_interp_qualifier interp_qualifier =
 231          brw->fragment_program->InterpQualifier[attr];
 232       bool is_gl_Color = attr == VARYING_SLOT_COL0 || attr == VARYING_SLOT_COL1;
 233       /* BRW_NEW_FS_PROG_DATA */
 234       int input_index = brw->wm.prog_data->urb_setup[attr];
 235
 236       if (input_index < 0)
 237          continue;
 238
 239       /* _NEW_POINT */
 240       bool point_sprite = false;
 241       if (drawing_points) {
 242          if (brw->ctx.Point.PointSprite &&
 243              (attr >= VARYING_SLOT_TEX0 && attr <= VARYING_SLOT_TEX7) &&
 244              brw->ctx.Point.CoordReplace[attr - VARYING_SLOT_TEX0]) {
 245             point_sprite = true;
 246          }
 247
 248          if (attr == VARYING_SLOT_PNTC)
 249             point_sprite = true;
 250
 251          if (point_sprite)
 252             *point_sprite_enables |= (1 << input_index);
 253       }
 254
 255       /* flat shading */
 256       if (interp_qualifier == INTERP_QUALIFIER_FLAT ||
 257           (shade_model_flat && is_gl_Color &&
 258            interp_qualifier == INTERP_QUALIFIER_NONE))
 259          *flat_enables |= (1 << input_index);
 260
 261       /* BRW_NEW_VUE_MAP_GEOM_OUT | _NEW_LIGHT | _NEW_PROGRAM */
 262       uint16_t attr_override = point_sprite ? 0 :
 263          get_attr_override(&brw->vue_map_geom_out,
 264                            *urb_entry_read_offset, attr,
 265                            brw->ctx.VertexProgram._TwoSideEnabled,
 266                            &max_source_attr);
 267
 268       /* The hardware can only do the overrides on 16 overrides at a
 269        * time, and the other up to 16 have to be lined up so that the
 270        * input index = the output index.  We'll need to do some
 271        * tweaking to make sure that's the case.
 272        */
 273       if (input_index < 16)
 274          attr_overrides[input_index] = attr_override;
 275       else
 276          assert(attr_override == input_index);
 277    }
 278
 279    /* From the Sandy Bridge PRM, Volume 2, Part 1, documentation for
 280     * 3DSTATE_SF DWord 1 bits 15:11, "Vertex URB Entry Read Length":
 281     *
 282     * "This field should be set to the minimum length required to read the
 283     *  maximum source attribute.  The maximum source attribute is indicated
 284     *  by the maximum value of the enabled Attribute # Source Attribute if
 285     *  Attribute Swizzle Enable is set, Number of Output Attributes-1 if
 286     *  enable is not set.
 287     *  read_length = ceiling((max_source_attr + 1) / 2)
 288     *
 289     *  [errata] Corruption/Hang possible if length programmed larger than
 290     *  recommended"
 291     *
 292     * Similar text exists for Ivy Bridge.
 293     */
 294    *urb_entry_read_length = ALIGN(max_source_attr + 1, 2) / 2;
 295 }
 296
 297
 298 static void
 299 upload_sf_state(struct brw_context *brw)
 300 {
 301    struct gl_context *ctx = &brw->ctx;
 302    /* BRW_NEW_FS_PROG_DATA */
 303    uint32_t num_outputs = brw->wm.prog_data->num_varying_inputs;
 304    uint32_t dw1, dw2, dw3, dw4;
 305    uint32_t point_sprite_enables;
 306    uint32_t flat_enables;
 307    int i;
 308    /* _NEW_BUFFER */
 309    bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
 310    const bool multisampled_fbo = _mesa_geometric_samples(ctx->DrawBuffer) > 1;
 311
 312    float point_size;
 313    uint16_t attr_overrides[16];
 314    uint32_t point_sprite_origin;
 315
 316    dw1 = GEN6_SF_SWIZZLE_ENABLE | num_outputs << GEN6_SF_NUM_OUTPUTS_SHIFT;
 317    dw2 = GEN6_SF_STATISTICS_ENABLE;
 318
 319    if (brw->sf.viewport_transform_enable)
 320        dw2 |= GEN6_SF_VIEWPORT_TRANSFORM_ENABLE;
 321
 322    dw3 = 0;
 323    dw4 = 0;
 324
 325    /* _NEW_POLYGON */
 326    if (ctx->Polygon._FrontBit == render_to_fbo)
 327       dw2 |= GEN6_SF_WINDING_CCW;
 328
 329    if (ctx->Polygon.OffsetFill)
 330        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_SOLID;
 331
 332    if (ctx->Polygon.OffsetLine)
 333        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_WIREFRAME;
 334
 335    if (ctx->Polygon.OffsetPoint)
 336        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_POINT;
 337
 338    switch (ctx->Polygon.FrontMode) {
 339    case GL_FILL:
 340        dw2 |= GEN6_SF_FRONT_SOLID;
 341        break;
 342
 343    case GL_LINE:
 344        dw2 |= GEN6_SF_FRONT_WIREFRAME;
 345        break;
 346
 347    case GL_POINT:
 348        dw2 |= GEN6_SF_FRONT_POINT;
 349        break;
 350
 351    default:
 352        unreachable("not reached");
 353    }
 354
 355    switch (ctx->Polygon.BackMode) {
 356    case GL_FILL:
 357        dw2 |= GEN6_SF_BACK_SOLID;
 358        break;
 359
 360    case GL_LINE:
 361        dw2 |= GEN6_SF_BACK_WIREFRAME;
 362        break;
 363
 364    case GL_POINT:
 365        dw2 |= GEN6_SF_BACK_POINT;
 366        break;
 367
 368    default:
 369        unreachable("not reached");
 370    }
 371
 372    /* _NEW_SCISSOR */
 373    if (ctx->Scissor.EnableFlags)
 374       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 375
 376    /* _NEW_POLYGON */
 377    if (ctx->Polygon.CullFlag) {
 378       switch (ctx->Polygon.CullFaceMode) {
 379       case GL_FRONT:
 380          dw3 |= GEN6_SF_CULL_FRONT;
 381          break;
 382       case GL_BACK:
 383          dw3 |= GEN6_SF_CULL_BACK;
 384          break;
 385       case GL_FRONT_AND_BACK:
 386          dw3 |= GEN6_SF_CULL_BOTH;
 387          break;
 388       default:
 389          unreachable("not reached");
 390       }
 391    } else {
 392       dw3 |= GEN6_SF_CULL_NONE;
 393    }
 394
 395    /* _NEW_LINE */
 396    {
 397       uint32_t line_width_u3_7 = brw_get_line_width(brw);
 398       dw3 |= line_width_u3_7 << GEN6_SF_LINE_WIDTH_SHIFT;
 399    }
 400    if (ctx->Line.SmoothFlag) {
 401       dw3 |= GEN6_SF_LINE_AA_ENABLE;
 402       dw3 |= GEN6_SF_LINE_AA_MODE_TRUE;
 403       dw3 |= GEN6_SF_LINE_END_CAP_WIDTH_1_0;
 404    }
 405    /* _NEW_MULTISAMPLE */
 406    if (multisampled_fbo && ctx->Multisample.Enabled)
 407       dw3 |= GEN6_SF_MSRAST_ON_PATTERN;
 408
 409    /* _NEW_PROGRAM | _NEW_POINT */
 410    if (!(ctx->VertexProgram.PointSizeEnabled ||
 411          ctx->Point._Attenuated))
 412       dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH;
 413
 414    /* Clamp to ARB_point_parameters user limits */
 415    point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, ctx->Point.MaxSize);
 416
 417    /* Clamp to the hardware limits and convert to fixed point */
 418    dw4 |= U_FIXED(CLAMP(point_size, 0.125f, 255.875f), 3);
 419
 420    /*
 421     * Window coordinates in an FBO are inverted, which means point
 422     * sprite origin must be inverted, too.
 423     */
 424    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo) {
 425       point_sprite_origin = GEN6_SF_POINT_SPRITE_LOWERLEFT;
 426    } else {
 427       point_sprite_origin = GEN6_SF_POINT_SPRITE_UPPERLEFT;
 428    }
 429    dw1 |= point_sprite_origin;
 430
 431    /* _NEW_LIGHT */
 432    if (ctx->Light.ProvokingVertex != GL_FIRST_VERTEX_CONVENTION) {
 433       dw4 |=
 434          (2 << GEN6_SF_TRI_PROVOKE_SHIFT) |
 435          (2 << GEN6_SF_TRIFAN_PROVOKE_SHIFT) |
 436          (1 << GEN6_SF_LINE_PROVOKE_SHIFT);
 437    } else {
 438       dw4 |=
 439          (1 << GEN6_SF_TRIFAN_PROVOKE_SHIFT);
 440    }
 441
 442    /* BRW_NEW_VUE_MAP_GEOM_OUT | BRW_NEW_FRAGMENT_PROGRAM |
 443     * _NEW_POINT | _NEW_LIGHT | _NEW_PROGRAM | BRW_NEW_FS_PROG_DATA
 444     */
 445    uint32_t urb_entry_read_length;
 446    uint32_t urb_entry_read_offset;
 447    calculate_attr_overrides(brw, attr_overrides, &point_sprite_enables,
 448                             &flat_enables, &urb_entry_read_length,
 449                             &urb_entry_read_offset);
 450    dw1 |= (urb_entry_read_length << GEN6_SF_URB_ENTRY_READ_LENGTH_SHIFT |
 451            urb_entry_read_offset << GEN6_SF_URB_ENTRY_READ_OFFSET_SHIFT);
 452
 453    BEGIN_BATCH(20);
 454    OUT_BATCH(_3DSTATE_SF << 16 | (20 - 2));
 455    OUT_BATCH(dw1);
 456    OUT_BATCH(dw2);
 457    OUT_BATCH(dw3);
 458    OUT_BATCH(dw4);
 459    OUT_BATCH_F(ctx->Polygon.OffsetUnits * 2); /* constant.  copied from gen4 */
 460    OUT_BATCH_F(ctx->Polygon.OffsetFactor); /* scale */
 461    OUT_BATCH_F(ctx->Polygon.OffsetClamp); /* global depth offset clamp */
 462    for (i = 0; i < 8; i++) {
 463       OUT_BATCH(attr_overrides[i * 2] | attr_overrides[i * 2 + 1] << 16);
 464    }
 465    OUT_BATCH(point_sprite_enables); /* dw16 */
 466    OUT_BATCH(flat_enables);
 467    OUT_BATCH(0); /* wrapshortest enables 0-7 */
 468    OUT_BATCH(0); /* wrapshortest enables 8-15 */
 469    ADVANCE_BATCH();
 470 }
 471
 472 const struct brw_tracked_state gen6_sf_state = {
 473    .dirty = {
 474       .mesa  = _NEW_BUFFERS |
 475                _NEW_LIGHT |
 476                _NEW_LINE |
 477                _NEW_MULTISAMPLE |
 478                _NEW_POINT |
 479                _NEW_POLYGON |
 480                _NEW_PROGRAM |
 481                _NEW_SCISSOR,
 482       .brw   = BRW_NEW_CONTEXT |
 483                BRW_NEW_FRAGMENT_PROGRAM |
 484                BRW_NEW_FS_PROG_DATA |
 485                BRW_NEW_GEOMETRY_PROGRAM |
 486                BRW_NEW_PRIMITIVE |
 487                BRW_NEW_VUE_MAP_GEOM_OUT,
 488    },
 489    .emit = upload_sf_state,
 490 };