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 "intel_batchbuffer.h"
  34
  35 /**
  36  * Determine the appropriate attribute override value to store into the
  37  * 3DSTATE_SF structure for a given fragment shader attribute.  The attribute
  38  * override value contains two pieces of information: the location of the
  39  * attribute in the VUE (relative to urb_entry_read_offset, see below), and a
  40  * flag indicating whether to "swizzle" the attribute based on the direction
  41  * the triangle is facing.
  42  *
  43  * If an attribute is "swizzled", then the given VUE location is used for
  44  * front-facing triangles, and the VUE location that immediately follows is
  45  * used for back-facing triangles.  We use this to implement the mapping from
  46  * gl_FrontColor/gl_BackColor to gl_Color.
  47  *
  48  * urb_entry_read_offset is the offset into the VUE at which the SF unit is
  49  * being instructed to begin reading attribute data.  It can be set to a
  50  * nonzero value to prevent the SF unit from wasting time reading elements of
  51  * the VUE that are not needed by the fragment shader.  It is measured in
  52  * 256-bit increments.
  53  */
  54 uint32_t
  55 get_attr_override(struct brw_vue_map *vue_map, int urb_entry_read_offset,
  56                   int fs_attr, bool two_side_color)
  57 {
  58    int attr_override, slot;
  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    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    attr_override = slot - 2 * urb_entry_read_offset;
  92    assert (attr_override >= 0 && attr_override < 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    if (two_side_color) {
  99       if (vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL0 &&
 100           vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC0)
 101          attr_override |= (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 102       else if (vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL1 &&
 103                vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC1)
 104          attr_override |= (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 105    }
 106
 107    return attr_override;
 108 }
 109
 110 static void
 111 upload_sf_state(struct brw_context *brw)
 112 {
 113    struct intel_context *intel = &brw->intel;
 114    struct gl_context *ctx = &intel->ctx;
 115    uint32_t urb_entry_read_length;
 116    /* BRW_NEW_FRAGMENT_PROGRAM */
 117    uint32_t num_outputs = _mesa_bitcount_64(brw->fragment_program->Base.InputsRead);
 118    /* _NEW_LIGHT */
 119    bool shade_model_flat = ctx->Light.ShadeModel == GL_FLAT;
 120    uint32_t dw1, dw2, dw3, dw4, dw16, dw17;
 121    int i;
 122    /* _NEW_BUFFER */
 123    bool render_to_fbo = brw->intel.ctx.DrawBuffer->Name != 0;
 124    int attr = 0, input_index = 0;
 125    int urb_entry_read_offset = 1;
 126    float point_size;
 127    uint16_t attr_overrides[FRAG_ATTRIB_MAX];
 128    uint32_t point_sprite_origin;
 129
 130    /* CACHE_NEW_VS_PROG */
 131    urb_entry_read_length = ((brw->vs.prog_data->vue_map.num_slots + 1) / 2 -
 132                             urb_entry_read_offset);
 133    if (urb_entry_read_length == 0) {
 134       /* Setting the URB entry read length to 0 causes undefined behavior, so
 135        * if we have no URB data to read, set it to 1.
 136        */
 137       urb_entry_read_length = 1;
 138    }
 139
 140    dw1 =
 141       GEN6_SF_SWIZZLE_ENABLE |
 142       num_outputs << GEN6_SF_NUM_OUTPUTS_SHIFT |
 143       urb_entry_read_length << GEN6_SF_URB_ENTRY_READ_LENGTH_SHIFT |
 144       urb_entry_read_offset << GEN6_SF_URB_ENTRY_READ_OFFSET_SHIFT;
 145
 146    dw2 = GEN6_SF_STATISTICS_ENABLE |
 147          GEN6_SF_VIEWPORT_TRANSFORM_ENABLE;
 148
 149    dw3 = 0;
 150    dw4 = 0;
 151    dw16 = 0;
 152    dw17 = 0;
 153
 154    /* _NEW_POLYGON */
 155    if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
 156       dw2 |= GEN6_SF_WINDING_CCW;
 157
 158    if (ctx->Polygon.OffsetFill)
 159        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_SOLID;
 160
 161    if (ctx->Polygon.OffsetLine)
 162        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_WIREFRAME;
 163
 164    if (ctx->Polygon.OffsetPoint)
 165        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_POINT;
 166
 167    switch (ctx->Polygon.FrontMode) {
 168    case GL_FILL:
 169        dw2 |= GEN6_SF_FRONT_SOLID;
 170        break;
 171
 172    case GL_LINE:
 173        dw2 |= GEN6_SF_FRONT_WIREFRAME;
 174        break;
 175
 176    case GL_POINT:
 177        dw2 |= GEN6_SF_FRONT_POINT;
 178        break;
 179
 180    default:
 181        assert(0);
 182        break;
 183    }
 184
 185    switch (ctx->Polygon.BackMode) {
 186    case GL_FILL:
 187        dw2 |= GEN6_SF_BACK_SOLID;
 188        break;
 189
 190    case GL_LINE:
 191        dw2 |= GEN6_SF_BACK_WIREFRAME;
 192        break;
 193
 194    case GL_POINT:
 195        dw2 |= GEN6_SF_BACK_POINT;
 196        break;
 197
 198    default:
 199        assert(0);
 200        break;
 201    }
 202
 203    /* _NEW_SCISSOR */
 204    if (ctx->Scissor.Enabled)
 205       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 206
 207    /* _NEW_POLYGON */
 208    if (ctx->Polygon.CullFlag) {
 209       switch (ctx->Polygon.CullFaceMode) {
 210       case GL_FRONT:
 211          dw3 |= GEN6_SF_CULL_FRONT;
 212          break;
 213       case GL_BACK:
 214          dw3 |= GEN6_SF_CULL_BACK;
 215          break;
 216       case GL_FRONT_AND_BACK:
 217          dw3 |= GEN6_SF_CULL_BOTH;
 218          break;
 219       default:
 220          assert(0);
 221          break;
 222       }
 223    } else {
 224       dw3 |= GEN6_SF_CULL_NONE;
 225    }
 226
 227    /* _NEW_LINE */
 228    dw3 |= U_FIXED(CLAMP(ctx->Line.Width, 0.0, 7.99), 7) <<
 229       GEN6_SF_LINE_WIDTH_SHIFT;
 230    if (ctx->Line.SmoothFlag) {
 231       dw3 |= GEN6_SF_LINE_AA_ENABLE;
 232       dw3 |= GEN6_SF_LINE_AA_MODE_TRUE;
 233       dw3 |= GEN6_SF_LINE_END_CAP_WIDTH_1_0;
 234    }
 235
 236    /* _NEW_PROGRAM | _NEW_POINT */
 237    if (!(ctx->VertexProgram.PointSizeEnabled ||
 238          ctx->Point._Attenuated))
 239       dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH;
 240
 241    /* Clamp to ARB_point_parameters user limits */
 242    point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, ctx->Point.MaxSize);
 243
 244    /* Clamp to the hardware limits and convert to fixed point */
 245    dw4 |= U_FIXED(CLAMP(point_size, 0.125, 255.875), 3);
 246
 247    /*
 248     * Window coordinates in an FBO are inverted, which means point
 249     * sprite origin must be inverted, too.
 250     */
 251    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo) {
 252       point_sprite_origin = GEN6_SF_POINT_SPRITE_LOWERLEFT;
 253    } else {
 254       point_sprite_origin = GEN6_SF_POINT_SPRITE_UPPERLEFT;
 255    }
 256    dw1 |= point_sprite_origin;
 257
 258    /* _NEW_LIGHT */
 259    if (ctx->Light.ProvokingVertex != GL_FIRST_VERTEX_CONVENTION) {
 260       dw4 |=
 261          (2 << GEN6_SF_TRI_PROVOKE_SHIFT) |
 262          (2 << GEN6_SF_TRIFAN_PROVOKE_SHIFT) |
 263          (1 << GEN6_SF_LINE_PROVOKE_SHIFT);
 264    } else {
 265       dw4 |=
 266          (1 << GEN6_SF_TRIFAN_PROVOKE_SHIFT);
 267    }
 268
 269    /* Create the mapping from the FS inputs we produce to the VS outputs
 270     * they source from.
 271     */
 272    for (; attr < FRAG_ATTRIB_MAX; attr++) {
 273       enum glsl_interp_qualifier interp_qualifier =
 274          brw->fragment_program->InterpQualifier[attr];
 275       bool is_gl_Color = attr == FRAG_ATTRIB_COL0 || attr == FRAG_ATTRIB_COL1;
 276
 277       if (!(brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(attr)))
 278          continue;
 279
 280       /* _NEW_POINT */
 281       if (ctx->Point.PointSprite &&
 282           (attr >= FRAG_ATTRIB_TEX0 && attr <= FRAG_ATTRIB_TEX7) &&
 283           ctx->Point.CoordReplace[attr - FRAG_ATTRIB_TEX0]) {
 284          dw16 |= (1 << input_index);
 285       }
 286
 287       if (attr == FRAG_ATTRIB_PNTC)
 288          dw16 |= (1 << input_index);
 289
 290       /* flat shading */
 291       if (interp_qualifier == INTERP_QUALIFIER_FLAT ||
 292           (shade_model_flat && is_gl_Color &&
 293            interp_qualifier == INTERP_QUALIFIER_NONE))
 294          dw17 |= (1 << input_index);
 295
 296       /* The hardware can only do the overrides on 16 overrides at a
 297        * time, and the other up to 16 have to be lined up so that the
 298        * input index = the output index.  We'll need to do some
 299        * tweaking to make sure that's the case.
 300        */
 301       assert(input_index < 16 || attr == input_index);
 302
 303       /* CACHE_NEW_VS_PROG | _NEW_LIGHT | _NEW_PROGRAM */
 304       attr_overrides[input_index++] =
 305          get_attr_override(&brw->vs.prog_data->vue_map,
 306                            urb_entry_read_offset, attr,
 307                            ctx->VertexProgram._TwoSideEnabled);
 308    }
 309
 310    for (; input_index < FRAG_ATTRIB_MAX; input_index++)
 311       attr_overrides[input_index] = 0;
 312
 313    BEGIN_BATCH(20);
 314    OUT_BATCH(_3DSTATE_SF << 16 | (20 - 2));
 315    OUT_BATCH(dw1);
 316    OUT_BATCH(dw2);
 317    OUT_BATCH(dw3);
 318    OUT_BATCH(dw4);
 319    OUT_BATCH_F(ctx->Polygon.OffsetUnits * 2); /* constant.  copied from gen4 */
 320    OUT_BATCH_F(ctx->Polygon.OffsetFactor); /* scale */
 321    OUT_BATCH_F(0.0); /* XXX: global depth offset clamp */
 322    for (i = 0; i < 8; i++) {
 323       OUT_BATCH(attr_overrides[i * 2] | attr_overrides[i * 2 + 1] << 16);
 324    }
 325    OUT_BATCH(dw16); /* point sprite texcoord bitmask */
 326    OUT_BATCH(dw17); /* constant interp bitmask */
 327    OUT_BATCH(0); /* wrapshortest enables 0-7 */
 328    OUT_BATCH(0); /* wrapshortest enables 8-15 */
 329    ADVANCE_BATCH();
 330 }
 331
 332 const struct brw_tracked_state gen6_sf_state = {
 333    .dirty = {
 334       .mesa  = (_NEW_LIGHT |
 335                 _NEW_PROGRAM |
 336                 _NEW_POLYGON |
 337                 _NEW_LINE |
 338                 _NEW_SCISSOR |
 339                 _NEW_BUFFERS |
 340                 _NEW_POINT),
 341       .brw   = (BRW_NEW_CONTEXT |
 342                 BRW_NEW_FRAGMENT_PROGRAM),
 343       .cache = CACHE_NEW_VS_PROG
 344    },
 345    .emit = upload_sf_state,
 346 };