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)
  58 {
  59    int attr_override, slot;
  60    int vs_attr = _mesa_frag_attrib_to_vert_result(fs_attr);
  61    if (vs_attr < 0 || vs_attr == VERT_RESULT_HPOS) {
  62       /* These attributes will be overwritten by the fragment shader's
  63        * interpolation code (see emit_interp() in brw_wm_fp.c), so just let
  64        * them reference the first available attribute.
  65        */
  66       return 0;
  67    }
  68
  69    /* Find the VUE slot for this attribute. */
  70    slot = vue_map->vert_result_to_slot[vs_attr];
  71
  72    /* If there was only a back color written but not front, use back
  73     * as the color instead of undefined
  74     */
  75    if (slot == -1 && vs_attr == VERT_RESULT_COL0)
  76       slot = vue_map->vert_result_to_slot[VERT_RESULT_BFC0];
  77    if (slot == -1 && vs_attr == VERT_RESULT_COL1)
  78       slot = vue_map->vert_result_to_slot[VERT_RESULT_BFC1];
  79
  80    if (slot == -1) {
  81       /* This attribute does not exist in the VUE--that means that the vertex
  82        * shader did not write to it.  Behavior is undefined in this case, so
  83        * just reference the first available attribute.
  84        */
  85       return 0;
  86    }
  87
  88    /* Compute the location of the attribute relative to urb_entry_read_offset.
  89     * Each increment of urb_entry_read_offset represents a 256-bit value, so
  90     * it counts for two 128-bit VUE slots.
  91     */
  92    attr_override = slot - 2 * urb_entry_read_offset;
  93    assert (attr_override >= 0 && attr_override < 32);
  94
  95    /* If we are doing two-sided color, and the VUE slot following this one
  96     * represents a back-facing color, then we need to instruct the SF unit to
  97     * do back-facing swizzling.
  98     */
  99    if (two_side_color) {
 100       if (vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL0 &&
 101           vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC0)
 102          attr_override |= (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 103       else if (vue_map->slot_to_vert_result[slot] == VERT_RESULT_COL1 &&
 104                vue_map->slot_to_vert_result[slot+1] == VERT_RESULT_BFC1)
 105          attr_override |= (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT);
 106    }
 107
 108    return attr_override;
 109 }
 110
 111 static void
 112 upload_sf_state(struct brw_context *brw)
 113 {
 114    struct intel_context *intel = &brw->intel;
 115    struct gl_context *ctx = &intel->ctx;
 116    uint32_t urb_entry_read_length;
 117    /* BRW_NEW_FRAGMENT_PROGRAM */
 118    uint32_t num_outputs = _mesa_bitcount_64(brw->fragment_program->Base.InputsRead);
 119    /* _NEW_LIGHT */
 120    bool shade_model_flat = ctx->Light.ShadeModel == GL_FLAT;
 121    uint32_t dw1, dw2, dw3, dw4, dw16, dw17;
 122    int i;
 123    /* _NEW_BUFFER */
 124    bool render_to_fbo = _mesa_is_user_fbo(brw->intel.ctx.DrawBuffer);
 125    bool multisampled_fbo = false;
 126    if (ctx->DrawBuffer->_ColorDrawBuffers[0])
 127       multisampled_fbo = ctx->DrawBuffer->_ColorDrawBuffers[0]->NumSamples > 0;
 128
 129    int attr = 0, input_index = 0;
 130    int urb_entry_read_offset = 1;
 131    float point_size;
 132    uint16_t attr_overrides[FRAG_ATTRIB_MAX];
 133    uint32_t point_sprite_origin;
 134
 135    /* CACHE_NEW_VS_PROG */
 136    urb_entry_read_length = ((brw->vs.prog_data->vue_map.num_slots + 1) / 2 -
 137                             urb_entry_read_offset);
 138    if (urb_entry_read_length == 0) {
 139       /* Setting the URB entry read length to 0 causes undefined behavior, so
 140        * if we have no URB data to read, set it to 1.
 141        */
 142       urb_entry_read_length = 1;
 143    }
 144
 145    dw1 =
 146       GEN6_SF_SWIZZLE_ENABLE |
 147       num_outputs << GEN6_SF_NUM_OUTPUTS_SHIFT |
 148       urb_entry_read_length << GEN6_SF_URB_ENTRY_READ_LENGTH_SHIFT |
 149       urb_entry_read_offset << GEN6_SF_URB_ENTRY_READ_OFFSET_SHIFT;
 150
 151    dw2 = GEN6_SF_STATISTICS_ENABLE |
 152          GEN6_SF_VIEWPORT_TRANSFORM_ENABLE;
 153
 154    dw3 = 0;
 155    dw4 = 0;
 156    dw16 = 0;
 157    dw17 = 0;
 158
 159    /* _NEW_POLYGON */
 160    if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
 161       dw2 |= GEN6_SF_WINDING_CCW;
 162
 163    if (ctx->Polygon.OffsetFill)
 164        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_SOLID;
 165
 166    if (ctx->Polygon.OffsetLine)
 167        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_WIREFRAME;
 168
 169    if (ctx->Polygon.OffsetPoint)
 170        dw2 |= GEN6_SF_GLOBAL_DEPTH_OFFSET_POINT;
 171
 172    switch (ctx->Polygon.FrontMode) {
 173    case GL_FILL:
 174        dw2 |= GEN6_SF_FRONT_SOLID;
 175        break;
 176
 177    case GL_LINE:
 178        dw2 |= GEN6_SF_FRONT_WIREFRAME;
 179        break;
 180
 181    case GL_POINT:
 182        dw2 |= GEN6_SF_FRONT_POINT;
 183        break;
 184
 185    default:
 186        assert(0);
 187        break;
 188    }
 189
 190    switch (ctx->Polygon.BackMode) {
 191    case GL_FILL:
 192        dw2 |= GEN6_SF_BACK_SOLID;
 193        break;
 194
 195    case GL_LINE:
 196        dw2 |= GEN6_SF_BACK_WIREFRAME;
 197        break;
 198
 199    case GL_POINT:
 200        dw2 |= GEN6_SF_BACK_POINT;
 201        break;
 202
 203    default:
 204        assert(0);
 205        break;
 206    }
 207
 208    /* _NEW_SCISSOR */
 209    if (ctx->Scissor.Enabled)
 210       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 211
 212    /* _NEW_POLYGON */
 213    if (ctx->Polygon.CullFlag) {
 214       switch (ctx->Polygon.CullFaceMode) {
 215       case GL_FRONT:
 216          dw3 |= GEN6_SF_CULL_FRONT;
 217          break;
 218       case GL_BACK:
 219          dw3 |= GEN6_SF_CULL_BACK;
 220          break;
 221       case GL_FRONT_AND_BACK:
 222          dw3 |= GEN6_SF_CULL_BOTH;
 223          break;
 224       default:
 225          assert(0);
 226          break;
 227       }
 228    } else {
 229       dw3 |= GEN6_SF_CULL_NONE;
 230    }
 231
 232    /* _NEW_LINE */
 233    {
 234       uint32_t line_width_u3_7 = U_FIXED(CLAMP(ctx->Line.Width, 0.0, 7.99), 7);
 235       /* TODO: line width of 0 is not allowed when MSAA enabled */
 236       if (line_width_u3_7 == 0)
 237          line_width_u3_7 = 1;
 238       dw3 |= line_width_u3_7 << GEN6_SF_LINE_WIDTH_SHIFT;
 239    }
 240    if (ctx->Line.SmoothFlag) {
 241       dw3 |= GEN6_SF_LINE_AA_ENABLE;
 242       dw3 |= GEN6_SF_LINE_AA_MODE_TRUE;
 243       dw3 |= GEN6_SF_LINE_END_CAP_WIDTH_1_0;
 244    }
 245    /* _NEW_MULTISAMPLE */
 246    if (multisampled_fbo && ctx->Multisample.Enabled)
 247       dw3 |= GEN6_SF_MSRAST_ON_PATTERN;
 248
 249    /* _NEW_PROGRAM | _NEW_POINT */
 250    if (!(ctx->VertexProgram.PointSizeEnabled ||
 251          ctx->Point._Attenuated))
 252       dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH;
 253
 254    /* Clamp to ARB_point_parameters user limits */
 255    point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, ctx->Point.MaxSize);
 256
 257    /* Clamp to the hardware limits and convert to fixed point */
 258    dw4 |= U_FIXED(CLAMP(point_size, 0.125, 255.875), 3);
 259
 260    /*
 261     * Window coordinates in an FBO are inverted, which means point
 262     * sprite origin must be inverted, too.
 263     */
 264    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo) {
 265       point_sprite_origin = GEN6_SF_POINT_SPRITE_LOWERLEFT;
 266    } else {
 267       point_sprite_origin = GEN6_SF_POINT_SPRITE_UPPERLEFT;
 268    }
 269    dw1 |= point_sprite_origin;
 270
 271    /* _NEW_LIGHT */
 272    if (ctx->Light.ProvokingVertex != GL_FIRST_VERTEX_CONVENTION) {
 273       dw4 |=
 274          (2 << GEN6_SF_TRI_PROVOKE_SHIFT) |
 275          (2 << GEN6_SF_TRIFAN_PROVOKE_SHIFT) |
 276          (1 << GEN6_SF_LINE_PROVOKE_SHIFT);
 277    } else {
 278       dw4 |=
 279          (1 << GEN6_SF_TRIFAN_PROVOKE_SHIFT);
 280    }
 281
 282    /* Create the mapping from the FS inputs we produce to the VS outputs
 283     * they source from.
 284     */
 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    }
 322
 323    for (; input_index < FRAG_ATTRIB_MAX; input_index++)
 324       attr_overrides[input_index] = 0;
 325
 326    BEGIN_BATCH(20);
 327    OUT_BATCH(_3DSTATE_SF << 16 | (20 - 2));
 328    OUT_BATCH(dw1);
 329    OUT_BATCH(dw2);
 330    OUT_BATCH(dw3);
 331    OUT_BATCH(dw4);
 332    OUT_BATCH_F(ctx->Polygon.OffsetUnits * 2); /* constant.  copied from gen4 */
 333    OUT_BATCH_F(ctx->Polygon.OffsetFactor); /* scale */
 334    OUT_BATCH_F(0.0); /* XXX: global depth offset clamp */
 335    for (i = 0; i < 8; i++) {
 336       OUT_BATCH(attr_overrides[i * 2] | attr_overrides[i * 2 + 1] << 16);
 337    }
 338    OUT_BATCH(dw16); /* point sprite texcoord bitmask */
 339    OUT_BATCH(dw17); /* constant interp bitmask */
 340    OUT_BATCH(0); /* wrapshortest enables 0-7 */
 341    OUT_BATCH(0); /* wrapshortest enables 8-15 */
 342    ADVANCE_BATCH();
 343 }
 344
 345 const struct brw_tracked_state gen6_sf_state = {
 346    .dirty = {
 347       .mesa  = (_NEW_LIGHT |
 348                 _NEW_PROGRAM |
 349                 _NEW_POLYGON |
 350                 _NEW_LINE |
 351                 _NEW_SCISSOR |
 352                 _NEW_BUFFERS |
 353                 _NEW_POINT |
 354                 _NEW_MULTISAMPLE),
 355       .brw   = (BRW_NEW_CONTEXT |
 356                 BRW_NEW_FRAGMENT_PROGRAM),
 357       .cache = CACHE_NEW_VS_PROG
 358    },
 359    .emit = upload_sf_state,
 360 };