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 /**
 151  * Create the mapping from the FS inputs we produce to the previous pipeline
 152  * stage (GS or VS) outputs they source from.
 153  */
 154 void
 155 calculate_attr_overrides(const struct brw_context *brw,
 156                          uint16_t *attr_overrides,
 157                          uint32_t *point_sprite_enables,
 158                          uint32_t *urb_entry_read_length,
 159                          uint32_t *urb_entry_read_offset)
 160 {
 161    uint32_t max_source_attr = 0;
 162
 163    *point_sprite_enables = 0;
 164
 165    *urb_entry_read_offset = BRW_SF_URB_ENTRY_READ_OFFSET;
 166
 167    /* BRW_NEW_FRAGMENT_PROGRAM
 168     *
 169     * If the fragment shader reads VARYING_SLOT_LAYER, then we need to pass in
 170     * the full vertex header.  Otherwise, we can program the SF to start
 171     * reading at an offset of 1 (2 varying slots) to skip unnecessary data:
 172     * - VARYING_SLOT_PSIZ and BRW_VARYING_SLOT_NDC on gen4-5
 173     * - VARYING_SLOT_{PSIZ,LAYER} and VARYING_SLOT_POS on gen6+
 174     */
 175
 176    bool fs_needs_vue_header = brw->fragment_program->Base.InputsRead &
 177       (VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT);
 178
 179    *urb_entry_read_offset = fs_needs_vue_header ? 0 : 1;
 180
 181    /* From the Ivybridge PRM, Vol 2 Part 1, 3DSTATE_SBE,
 182     * description of dw10 Point Sprite Texture Coordinate Enable:
 183     *
 184     * "This field must be programmed to zero when non-point primitives
 185     * are rendered."
 186     *
 187     * The SandyBridge PRM doesn't explicitly say that point sprite enables
 188     * must be programmed to zero when rendering non-point primitives, but
 189     * the IvyBridge PRM does, and if we don't, we get garbage.
 190     *
 191     * This is not required on Haswell, as the hardware ignores this state
 192     * when drawing non-points -- although we do still need to be careful to
 193     * correctly set the attr overrides.
 194     *
 195     * _NEW_POLYGON
 196     * BRW_NEW_PRIMITIVE | BRW_NEW_GS_PROG_DATA | BRW_NEW_TES_PROG_DATA
 197     */
 198    bool drawing_points = brw_is_drawing_points(brw);
 199
 200    /* Initialize all the attr_overrides to 0.  In the loop below we'll modify
 201     * just the ones that correspond to inputs used by the fs.
 202     */
 203    memset(attr_overrides, 0, 16*sizeof(*attr_overrides));
 204
 205    for (int attr = 0; attr < VARYING_SLOT_MAX; attr++) {
 206       /* BRW_NEW_FS_PROG_DATA */
 207       int input_index = brw->wm.prog_data->urb_setup[attr];
 208
 209       if (input_index < 0)
 210          continue;
 211
 212       /* _NEW_POINT */
 213       bool point_sprite = false;
 214       if (drawing_points) {
 215          if (brw->ctx.Point.PointSprite &&
 216              (attr >= VARYING_SLOT_TEX0 && attr <= VARYING_SLOT_TEX7) &&
 217              (brw->ctx.Point.CoordReplace & (1u << (attr - VARYING_SLOT_TEX0)))) {
 218             point_sprite = true;
 219          }
 220
 221          if (attr == VARYING_SLOT_PNTC)
 222             point_sprite = true;
 223
 224          if (point_sprite)
 225             *point_sprite_enables |= (1 << input_index);
 226       }
 227
 228       /* BRW_NEW_VUE_MAP_GEOM_OUT | _NEW_LIGHT | _NEW_PROGRAM */
 229       uint16_t attr_override = point_sprite ? 0 :
 230          get_attr_override(&brw->vue_map_geom_out,
 231                            *urb_entry_read_offset, attr,
 232                            brw->ctx.VertexProgram._TwoSideEnabled,
 233                            &max_source_attr);
 234
 235       /* The hardware can only do the overrides on 16 overrides at a
 236        * time, and the other up to 16 have to be lined up so that the
 237        * input index = the output index.  We'll need to do some
 238        * tweaking to make sure that's the case.
 239        */
 240       if (input_index < 16)
 241          attr_overrides[input_index] = attr_override;
 242       else
 243          assert(attr_override == input_index);
 244    }
 245
 246    /* From the Sandy Bridge PRM, Volume 2, Part 1, documentation for
 247     * 3DSTATE_SF DWord 1 bits 15:11, "Vertex URB Entry Read Length":
 248     *
 249     * "This field should be set to the minimum length required to read the
 250     *  maximum source attribute.  The maximum source attribute is indicated
 251     *  by the maximum value of the enabled Attribute # Source Attribute if
 252     *  Attribute Swizzle Enable is set, Number of Output Attributes-1 if
 253     *  enable is not set.
 254     *  read_length = ceiling((max_source_attr + 1) / 2)
 255     *
 256     *  [errata] Corruption/Hang possible if length programmed larger than
 257     *  recommended"
 258     *
 259     * Similar text exists for Ivy Bridge.
 260     */
 261    *urb_entry_read_length = ALIGN(max_source_attr + 1, 2) / 2;
 262 }
 263
 264
 265 static void
 266 upload_sf_state(struct brw_context *brw)
 267 {
 268    struct gl_context *ctx = &brw->ctx;
 269    /* BRW_NEW_FS_PROG_DATA */
 270    uint32_t num_outputs = brw->wm.prog_data->num_varying_inputs;
 271    uint32_t dw1, dw2, dw3, dw4;
 272    uint32_t point_sprite_enables;
 273    int i;
 274    /* _NEW_BUFFER */
 275    bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
 276    const bool multisampled_fbo = _mesa_geometric_samples(ctx->DrawBuffer) > 1;
 277
 278    float point_size;
 279    uint16_t attr_overrides[16];
 280    uint32_t point_sprite_origin;
 281
 282    dw1 = GEN6_SF_SWIZZLE_ENABLE | num_outputs << GEN6_SF_NUM_OUTPUTS_SHIFT;
 283    dw2 = GEN6_SF_STATISTICS_ENABLE;
 284
 285    if (brw->sf.viewport_transform_enable)
 286        dw2 |= GEN6_SF_VIEWPORT_TRANSFORM_ENABLE;
 287
 288    dw3 = 0;
 289    dw4 = 0;
 290
 291    /* _NEW_POLYGON */
 292    if (ctx->Polygon._FrontBit == render_to_fbo)
 293       dw2 |= GEN6_SF_WINDING_CCW;
 294
 295    if (ctx->Polygon.OffsetFill)
 296        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_SOLID;
 297
 298    if (ctx->Polygon.OffsetLine)
 299        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_WIREFRAME;
 300
 301    if (ctx->Polygon.OffsetPoint)
 302        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_POINT;
 303
 304    switch (ctx->Polygon.FrontMode) {
 305    case GL_FILL:
 306        dw2 |= GEN6_SF_FRONT_SOLID;
 307        break;
 308
 309    case GL_LINE:
 310        dw2 |= GEN6_SF_FRONT_WIREFRAME;
 311        break;
 312
 313    case GL_POINT:
 314        dw2 |= GEN6_SF_FRONT_POINT;
 315        break;
 316
 317    default:
 318        unreachable("not reached");
 319    }
 320
 321    switch (ctx->Polygon.BackMode) {
 322    case GL_FILL:
 323        dw2 |= GEN6_SF_BACK_SOLID;
 324        break;
 325
 326    case GL_LINE:
 327        dw2 |= GEN6_SF_BACK_WIREFRAME;
 328        break;
 329
 330    case GL_POINT:
 331        dw2 |= GEN6_SF_BACK_POINT;
 332        break;
 333
 334    default:
 335        unreachable("not reached");
 336    }
 337
 338    /* _NEW_SCISSOR | _NEW_POLYGON,
 339     * BRW_NEW_GS_PROG_DATA | BRW_NEW_TES_PROG_DATA | BRW_NEW_PRIMITIVE
 340     */
 341    if (ctx->Scissor.EnableFlags ||
 342        brw_is_drawing_points(brw) || brw_is_drawing_lines(brw))
 343       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 344
 345    /* _NEW_POLYGON */
 346    if (ctx->Polygon.CullFlag) {
 347       switch (ctx->Polygon.CullFaceMode) {
 348       case GL_FRONT:
 349          dw3 |= GEN6_SF_CULL_FRONT;
 350          break;
 351       case GL_BACK:
 352          dw3 |= GEN6_SF_CULL_BACK;
 353          break;
 354       case GL_FRONT_AND_BACK:
 355          dw3 |= GEN6_SF_CULL_BOTH;
 356          break;
 357       default:
 358          unreachable("not reached");
 359       }
 360    } else {
 361       dw3 |= GEN6_SF_CULL_NONE;
 362    }
 363
 364    /* _NEW_LINE */
 365    {
 366       uint32_t line_width_u3_7 = brw_get_line_width(brw);
 367       dw3 |= line_width_u3_7 << GEN6_SF_LINE_WIDTH_SHIFT;
 368    }
 369    if (ctx->Line.SmoothFlag) {
 370       dw3 |= GEN6_SF_LINE_AA_ENABLE;
 371       dw3 |= GEN6_SF_LINE_AA_MODE_TRUE;
 372       dw3 |= GEN6_SF_LINE_END_CAP_WIDTH_1_0;
 373    }
 374    /* _NEW_MULTISAMPLE */
 375    if (multisampled_fbo && ctx->Multisample.Enabled)
 376       dw3 |= GEN6_SF_MSRAST_ON_PATTERN;
 377
 378    /* _NEW_PROGRAM | _NEW_POINT, BRW_NEW_VUE_MAP_GEOM_OUT */
 379    if (use_state_point_size(brw))
 380       dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH;
 381
 382    /* _NEW_POINT - Clamp to ARB_point_parameters user limits */
 383    point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, ctx->Point.MaxSize);
 384
 385    /* Clamp to the hardware limits and convert to fixed point */
 386    dw4 |= U_FIXED(CLAMP(point_size, 0.125f, 255.875f), 3);
 387
 388    /*
 389     * Window coordinates in an FBO are inverted, which means point
 390     * sprite origin must be inverted, too.
 391     */
 392    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo) {
 393       point_sprite_origin = GEN6_SF_POINT_SPRITE_LOWERLEFT;
 394    } else {
 395       point_sprite_origin = GEN6_SF_POINT_SPRITE_UPPERLEFT;
 396    }
 397    dw1 |= point_sprite_origin;
 398
 399    /* _NEW_LIGHT */
 400    if (ctx->Light.ProvokingVertex != GL_FIRST_VERTEX_CONVENTION) {
 401       dw4 |=
 402          (2 << GEN6_SF_TRI_PROVOKE_SHIFT) |
 403          (2 << GEN6_SF_TRIFAN_PROVOKE_SHIFT) |
 404          (1 << GEN6_SF_LINE_PROVOKE_SHIFT);
 405    } else {
 406       dw4 |=
 407          (1 << GEN6_SF_TRIFAN_PROVOKE_SHIFT);
 408    }
 409
 410    /* BRW_NEW_VUE_MAP_GEOM_OUT | BRW_NEW_FRAGMENT_PROGRAM |
 411     * _NEW_POINT | _NEW_LIGHT | _NEW_PROGRAM | BRW_NEW_FS_PROG_DATA
 412     */
 413    uint32_t urb_entry_read_length;
 414    uint32_t urb_entry_read_offset;
 415    calculate_attr_overrides(brw, attr_overrides, &point_sprite_enables,
 416                             &urb_entry_read_length, &urb_entry_read_offset);
 417    dw1 |= (urb_entry_read_length << GEN6_SF_URB_ENTRY_READ_LENGTH_SHIFT |
 418            urb_entry_read_offset << GEN6_SF_URB_ENTRY_READ_OFFSET_SHIFT);
 419
 420    BEGIN_BATCH(20);
 421    OUT_BATCH(_3DSTATE_SF << 16 | (20 - 2));
 422    OUT_BATCH(dw1);
 423    OUT_BATCH(dw2);
 424    OUT_BATCH(dw3);
 425    OUT_BATCH(dw4);
 426    OUT_BATCH_F(ctx->Polygon.OffsetUnits * 2); /* constant.  copied from gen4 */
 427    OUT_BATCH_F(ctx->Polygon.OffsetFactor); /* scale */
 428    OUT_BATCH_F(ctx->Polygon.OffsetClamp); /* global depth offset clamp */
 429    for (i = 0; i < 8; i++) {
 430       OUT_BATCH(attr_overrides[i * 2] | attr_overrides[i * 2 + 1] << 16);
 431    }
 432    OUT_BATCH(point_sprite_enables); /* dw16 */
 433    OUT_BATCH(brw->wm.prog_data->flat_inputs);
 434    OUT_BATCH(0); /* wrapshortest enables 0-7 */
 435    OUT_BATCH(0); /* wrapshortest enables 8-15 */
 436    ADVANCE_BATCH();
 437 }
 438
 439 const struct brw_tracked_state gen6_sf_state = {
 440    .dirty = {
 441       .mesa  = _NEW_BUFFERS |
 442                _NEW_LIGHT |
 443                _NEW_LINE |
 444                _NEW_MULTISAMPLE |
 445                _NEW_POINT |
 446                _NEW_POLYGON |
 447                _NEW_PROGRAM |
 448                _NEW_SCISSOR,
 449       .brw   = BRW_NEW_BLORP |
 450                BRW_NEW_CONTEXT |
 451                BRW_NEW_FRAGMENT_PROGRAM |
 452                BRW_NEW_FS_PROG_DATA |
 453                BRW_NEW_GS_PROG_DATA |
 454                BRW_NEW_PRIMITIVE |
 455                BRW_NEW_TES_PROG_DATA |
 456                BRW_NEW_VUE_MAP_GEOM_OUT,
 457    },
 458    .emit = upload_sf_state,
 459 };