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 "intel_batchbuffer.h"
  35
  36 /**
  37  * Determine the appropriate attribute override value to store into the
  38  * 3DSTATE_SF structure for a given fragment shader attribute.  The attribute
  39  * override value contains two pieces of information: the location of the
  40  * attribute in the VUE (relative to urb_entry_read_offset, see below), and a
  41  * flag indicating whether to "swizzle" the attribute based on the direction
  42  * the triangle is facing.
  43  *
  44  * If an attribute is "swizzled", then the given VUE location is used for
  45  * front-facing triangles, and the VUE location that immediately follows is
  46  * used for back-facing triangles.  We use this to implement the mapping from
  47  * gl_FrontColor/gl_BackColor to gl_Color.
  48  *
  49  * urb_entry_read_offset is the offset into the VUE at which the SF unit is
  50  * being instructed to begin reading attribute data.  It can be set to a
  51  * nonzero value to prevent the SF unit from wasting time reading elements of
  52  * the VUE that are not needed by the fragment shader.  It is measured in
  53  * 256-bit increments.
  54  */
  55 uint32_t
  56 get_attr_override(struct brw_vue_map *vue_map, int urb_entry_read_offset,
  57                   int fs_attr, bool two_side_color, uint32_t *max_source_attr)
  58 {
  59    int vs_attr = _mesa_frag_attrib_to_vert_result(fs_attr);
  60    if (vs_attr < 0 || vs_attr == VERT_RESULT_HPOS) {
  61       /* These attributes will be overwritten by the fragment shader's
  62        * interpolation code (see emit_interp() in brw_wm_fp.c), so just let
  63        * them reference the first available attribute.
  64        */
  65       return 0;
  66    }
  67
  68    /* Find the VUE slot for this attribute. */
  69    int slot = vue_map->vert_result_to_slot[vs_attr];
  70
  71    /* If there was only a back color written but not front, use back
  72     * as the color instead of undefined
  73     */
  74    if (slot == -1 && vs_attr == VERT_RESULT_COL0)
  75       slot = vue_map->vert_result_to_slot[VERT_RESULT_BFC0];
  76    if (slot == -1 && vs_attr == VERT_RESULT_COL1)
  77       slot = vue_map->vert_result_to_slot[VERT_RESULT_BFC1];
  78
  79    if (slot == -1) {
  80       /* This attribute does not exist in the VUE--that means that the vertex
  81        * shader did not write to it.  This means that either:
  82        *
  83        * (a) This attribute is a texture coordinate, and it is going to be
  84        * replaced with point coordinates (as a consequence of a call to
  85        * glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE)), so the
  86        * hardware will ignore whatever attribute override we supply.
  87        *
  88        * (b) This attribute is read by the fragment shader but not written by
  89        * the vertex shader, so its value is undefined.  Therefore the
  90        * attribute override we supply doesn't matter.
  91        *
  92        * In either case the attribute override we supply doesn't matter, so
  93        * just reference the first available attribute.
  94        */
  95       return 0;
  96    }
  97
  98    /* Compute the location of the attribute relative to urb_entry_read_offset.
  99     * Each increment of urb_entry_read_offset represents a 256-bit value, so
 100     * it counts for two 128-bit VUE slots.
 101     */
 102    int source_attr = slot - 2 * urb_entry_read_offset;
 103    assert(source_attr >= 0 && source_attr < 32);
 104
 105    /* If we are doing two-sided color, and the VUE slot following this one
 106     * represents a back-facing color, then we need to instruct the SF unit to
 107     * do back-facing swizzling.
 108     */
 109    bool swizzling = two_side_color &&
 110       ((vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL0 &&
 111         vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC0) ||
 112        (vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL1 &&
 113         vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC1));
 114
 115    /* Update max_source_attr.  If swizzling, the SF will read this slot + 1. */
 116    if (*max_source_attr < source_attr + swizzling)
 117       *max_source_attr = source_attr + swizzling;
 118
 119    if (swizzling) {
 120       return source_attr |
 121          (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 122    }
 123
 124    return source_attr;
 125 }
 126
 127 static void
 128 upload_sf_state(struct brw_context *brw)
 129 {
 130    struct intel_context *intel = &brw->intel;
 131    struct gl_context *ctx = &intel->ctx;
 132    /* BRW_NEW_FRAGMENT_PROGRAM */
 133    uint32_t num_outputs = _mesa_bitcount_64(brw->fragment_program->Base.InputsRead);
 134    /* _NEW_LIGHT */
 135    bool shade_model_flat = ctx->Light.ShadeModel == GL_FLAT;
 136    uint32_t dw1, dw2, dw3, dw4, dw16, dw17;
 137    int i;
 138    /* _NEW_BUFFER */
 139    bool render_to_fbo = _mesa_is_user_fbo(brw->intel.ctx.DrawBuffer);
 140    bool multisampled_fbo = ctx->DrawBuffer->Visual.samples > 1;
 141
 142    int attr = 0, input_index = 0;
 143    int urb_entry_read_offset = 1;
 144    float point_size;
 145    uint16_t attr_overrides[FRAG_ATTRIB_MAX];
 146    uint32_t point_sprite_origin;
 147
 148    dw1 = GEN6_SF_SWIZZLE_ENABLE | num_outputs << GEN6_SF_NUM_OUTPUTS_SHIFT;
 149
 150    dw2 = GEN6_SF_STATISTICS_ENABLE |
 151          GEN6_SF_VIEWPORT_TRANSFORM_ENABLE;
 152
 153    dw3 = 0;
 154    dw4 = 0;
 155    dw16 = 0;
 156    dw17 = 0;
 157
 158    /* _NEW_POLYGON */
 159    if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
 160       dw2 |= GEN6_SF_WINDING_CCW;
 161
 162    if (ctx->Polygon.OffsetFill)
 163        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_SOLID;
 164
 165    if (ctx->Polygon.OffsetLine)
 166        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_WIREFRAME;
 167
 168    if (ctx->Polygon.OffsetPoint)
 169        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_POINT;
 170
 171    switch (ctx->Polygon.FrontMode) {
 172    case GL_FILL:
 173        dw2 |= GEN6_SF_FRONT_SOLID;
 174        break;
 175
 176    case GL_LINE:
 177        dw2 |= GEN6_SF_FRONT_WIREFRAME;
 178        break;
 179
 180    case GL_POINT:
 181        dw2 |= GEN6_SF_FRONT_POINT;
 182        break;
 183
 184    default:
 185        assert(0);
 186        break;
 187    }
 188
 189    switch (ctx->Polygon.BackMode) {
 190    case GL_FILL:
 191        dw2 |= GEN6_SF_BACK_SOLID;
 192        break;
 193
 194    case GL_LINE:
 195        dw2 |= GEN6_SF_BACK_WIREFRAME;
 196        break;
 197
 198    case GL_POINT:
 199        dw2 |= GEN6_SF_BACK_POINT;
 200        break;
 201
 202    default:
 203        assert(0);
 204        break;
 205    }
 206
 207    /* _NEW_SCISSOR */
 208    if (ctx->Scissor.Enabled)
 209       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 210
 211    /* _NEW_POLYGON */
 212    if (ctx->Polygon.CullFlag) {
 213       switch (ctx->Polygon.CullFaceMode) {
 214       case GL_FRONT:
 215          dw3 |= GEN6_SF_CULL_FRONT;
 216          break;
 217       case GL_BACK:
 218          dw3 |= GEN6_SF_CULL_BACK;
 219          break;
 220       case GL_FRONT_AND_BACK:
 221          dw3 |= GEN6_SF_CULL_BOTH;
 222          break;
 223       default:
 224          assert(0);
 225          break;
 226       }
 227    } else {
 228       dw3 |= GEN6_SF_CULL_NONE;
 229    }
 230
 231    /* _NEW_LINE */
 232    {
 233       uint32_t line_width_u3_7 = U_FIXED(CLAMP(ctx->Line.Width, 0.0, 7.99), 7);
 234       /* TODO: line width of 0 is not allowed when MSAA enabled */
 235       if (line_width_u3_7 == 0)
 236          line_width_u3_7 = 1;
 237       dw3 |= line_width_u3_7 << GEN6_SF_LINE_WIDTH_SHIFT;
 238    }
 239    if (ctx->Line.SmoothFlag) {
 240       dw3 |= GEN6_SF_LINE_AA_ENABLE;
 241       dw3 |= GEN6_SF_LINE_AA_MODE_TRUE;
 242       dw3 |= GEN6_SF_LINE_END_CAP_WIDTH_1_0;
 243    }
 244    /* _NEW_MULTISAMPLE */
 245    if (multisampled_fbo && ctx->Multisample.Enabled)
 246       dw3 |= GEN6_SF_MSRAST_ON_PATTERN;
 247
 248    /* _NEW_PROGRAM | _NEW_POINT */
 249    if (!(ctx->VertexProgram.PointSizeEnabled ||
 250          ctx->Point._Attenuated))
 251       dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH;
 252
 253    /* Clamp to ARB_point_parameters user limits */
 254    point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, ctx->Point.MaxSize);
 255
 256    /* Clamp to the hardware limits and convert to fixed point */
 257    dw4 |= U_FIXED(CLAMP(point_size, 0.125, 255.875), 3);
 258
 259    /*
 260     * Window coordinates in an FBO are inverted, which means point
 261     * sprite origin must be inverted, too.
 262     */
 263    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo) {
 264       point_sprite_origin = GEN6_SF_POINT_SPRITE_LOWERLEFT;
 265    } else {
 266       point_sprite_origin = GEN6_SF_POINT_SPRITE_UPPERLEFT;
 267    }
 268    dw1 |= point_sprite_origin;
 269
 270    /* _NEW_LIGHT */
 271    if (ctx->Light.ProvokingVertex != GL_FIRST_VERTEX_CONVENTION) {
 272       dw4 |=
 273          (2 << GEN6_SF_TRI_PROVOKE_SHIFT) |
 274          (2 << GEN6_SF_TRIFAN_PROVOKE_SHIFT) |
 275          (1 << GEN6_SF_LINE_PROVOKE_SHIFT);
 276    } else {
 277       dw4 |=
 278          (1 << GEN6_SF_TRIFAN_PROVOKE_SHIFT);
 279    }
 280
 281    /* Create the mapping from the FS inputs we produce to the VS outputs
 282     * they source from.
 283     */
 284    uint32_t max_source_attr = 0;
 285    for (; attr < FRAG_ATTRIB_MAX; attr++) {
 286       enum glsl_interp_qualifier interp_qualifier =
 287          brw->fragment_program->InterpQualifier[attr];
 288       bool is_gl_Color = attr == FRAG_ATTRIB_COL0 || attr == FRAG_ATTRIB_COL1;
 289
 290       if (!(brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(attr)))
 291          continue;
 292
 293       /* _NEW_POINT */
 294       if (ctx->Point.PointSprite &&
 295           (attr >= FRAG_ATTRIB_TEX0 && attr <= FRAG_ATTRIB_TEX7) &&
 296           ctx->Point.CoordReplace[attr - FRAG_ATTRIB_TEX0]) {
 297          dw16 |= (1 << input_index);
 298       }
 299
 300       if (attr == FRAG_ATTRIB_PNTC)
 301          dw16 |= (1 << input_index);
 302
 303       /* flat shading */
 304       if (interp_qualifier == INTERP_QUALIFIER_FLAT ||
 305           (shade_model_flat && is_gl_Color &&
 306            interp_qualifier == INTERP_QUALIFIER_NONE))
 307          dw17 |= (1 << input_index);
 308
 309       /* The hardware can only do the overrides on 16 overrides at a
 310        * time, and the other up to 16 have to be lined up so that the
 311        * input index = the output index.  We'll need to do some
 312        * tweaking to make sure that's the case.
 313        */
 314       assert(input_index < 16 || attr == input_index);
 315
 316       /* CACHE_NEW_VS_PROG | _NEW_LIGHT | _NEW_PROGRAM */
 317       attr_overrides[input_index++] =
 318          get_attr_override(&brw->vs.prog_data->vue_map,
 319                            urb_entry_read_offset, attr,
 320                            ctx->VertexProgram._TwoSideEnabled,
 321                            &max_source_attr);
 322    }
 323
 324    for (; input_index < FRAG_ATTRIB_MAX; input_index++)
 325       attr_overrides[input_index] = 0;
 326
 327    /* From the Sandy Bridge PRM, Volume 2, Part 1, documentation for
 328     * 3DSTATE_SF DWord 1 bits 15:11, "Vertex URB Entry Read Length":
 329     *
 330     * "This field should be set to the minimum length required to read the
 331     *  maximum source attribute.  The maximum source attribute is indicated
 332     *  by the maximum value of the enabled Attribute # Source Attribute if
 333     *  Attribute Swizzle Enable is set, Number of Output Attributes-1 if
 334     *  enable is not set.
 335     *  read_length = ceiling((max_source_attr + 1) / 2)
 336     *
 337     *  [errata] Corruption/Hang possible if length programmed larger than
 338     *  recommended"
 339     */
 340    uint32_t urb_entry_read_length = ALIGN(max_source_attr + 1, 2) / 2;
 341       dw1 |= urb_entry_read_length << GEN6_SF_URB_ENTRY_READ_LENGTH_SHIFT |
 342              urb_entry_read_offset << GEN6_SF_URB_ENTRY_READ_OFFSET_SHIFT;
 343
 344    BEGIN_BATCH(20);
 345    OUT_BATCH(_3DSTATE_SF << 16 | (20 - 2));
 346    OUT_BATCH(dw1);
 347    OUT_BATCH(dw2);
 348    OUT_BATCH(dw3);
 349    OUT_BATCH(dw4);
 350    OUT_BATCH_F(ctx->Polygon.OffsetUnits * 2); /* constant.  copied from gen4 */
 351    OUT_BATCH_F(ctx->Polygon.OffsetFactor); /* scale */
 352    OUT_BATCH_F(0.0); /* XXX: global depth offset clamp */
 353    for (i = 0; i < 8; i++) {
 354       OUT_BATCH(attr_overrides[i * 2] | attr_overrides[i * 2 + 1] << 16);
 355    }
 356    OUT_BATCH(dw16); /* point sprite texcoord bitmask */
 357    OUT_BATCH(dw17); /* constant interp bitmask */
 358    OUT_BATCH(0); /* wrapshortest enables 0-7 */
 359    OUT_BATCH(0); /* wrapshortest enables 8-15 */
 360    ADVANCE_BATCH();
 361 }
 362
 363 const struct brw_tracked_state gen6_sf_state = {
 364    .dirty = {
 365       .mesa  = (_NEW_LIGHT |
 366                 _NEW_PROGRAM |
 367                 _NEW_POLYGON |
 368                 _NEW_LINE |
 369                 _NEW_SCISSOR |
 370                 _NEW_BUFFERS |
 371                 _NEW_POINT |
 372                 _NEW_MULTISAMPLE),
 373       .brw   = (BRW_NEW_CONTEXT |
 374                 BRW_NEW_FRAGMENT_PROGRAM),
 375       .cache = CACHE_NEW_VS_PROG
 376    },
 377    .emit = upload_sf_state,
 378 };