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