src/mesa/drivers/dri/i965/gen6_clip_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 "intel_batchbuffer.h"
  33
  34 /**
  35  * Return true if at least one of the inputs used by the given fragment
  36  * program has the GLSL "noperspective" interpolation qualifier.
  37  */
  38 bool
  39 brw_fprog_uses_noperspective(const struct gl_fragment_program *fprog)
  40 {
  41    int attr;
  42    for (attr = 0; attr < FRAG_ATTRIB_MAX; ++attr) {
  43       /* Ignore unused inputs. */
  44       if (!(fprog->Base.InputsRead & BITFIELD64_BIT(attr)))
  45          continue;
  46
  47       if (fprog->InterpQualifier[attr] == INTERP_QUALIFIER_NOPERSPECTIVE)
  48          return true;
  49    }
  50    return false;
  51 }
  52
  53
  54 static void
  55 upload_clip_state(struct brw_context *brw)
  56 {
  57    struct intel_context *intel = &brw->intel;
  58    struct gl_context *ctx = &intel->ctx;
  59    uint32_t depth_clamp = 0;
  60    uint32_t provoking, userclip;
  61    uint32_t nonperspective_barycentric_enable_flag = 0;
  62    /* BRW_NEW_FRAGMENT_PROGRAM */
  63    const struct gl_fragment_program *fprog = brw->fragment_program;
  64
  65    if (brw_fprog_uses_noperspective(fprog)) {
  66       nonperspective_barycentric_enable_flag =
  67          GEN6_CLIP_NON_PERSPECTIVE_BARYCENTRIC_ENABLE;
  68    }
  69
  70    if (brw->hiz.op) {
  71       /* HiZ operations emit a rectangle primitive, which requires clipping to
  72        * be disabled. From page 10 of the Sandy Bridge PRM Volume 2 Part 1
  73        * Section 1.3 3D Primitives Overview:
  74        *    RECTLIST:
  75        *    Either the CLIP unit should be DISABLED, or the CLIP unit's Clip
  76        *    Mode should be set to a value other than CLIPMODE_NORMAL.
  77        */
  78       BEGIN_BATCH(4);
  79       OUT_BATCH(_3DSTATE_CLIP << 16 | (4 - 2));
  80       OUT_BATCH(0);
  81       OUT_BATCH(0);
  82       OUT_BATCH(0);
  83       ADVANCE_BATCH();
  84       return;
  85    }
  86
  87    if (!ctx->Transform.DepthClamp)
  88       depth_clamp = GEN6_CLIP_Z_TEST;
  89
  90    /* _NEW_LIGHT */
  91    if (ctx->Light.ProvokingVertex == GL_FIRST_VERTEX_CONVENTION) {
  92       provoking =
  93          (0 << GEN6_CLIP_TRI_PROVOKE_SHIFT) |
  94          (1 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT) |
  95          (0 << GEN6_CLIP_LINE_PROVOKE_SHIFT);
  96    } else {
  97       provoking =
  98          (2 << GEN6_CLIP_TRI_PROVOKE_SHIFT) |
  99          (2 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT) |
 100          (1 << GEN6_CLIP_LINE_PROVOKE_SHIFT);
 101    }
 102
 103    /* _NEW_TRANSFORM */
 104    userclip = ctx->Transform.ClipPlanesEnabled;
 105
 106    BEGIN_BATCH(4);
 107    OUT_BATCH(_3DSTATE_CLIP << 16 | (4 - 2));
 108    OUT_BATCH(GEN6_CLIP_STATISTICS_ENABLE);
 109    OUT_BATCH(GEN6_CLIP_ENABLE |
 110              GEN6_CLIP_API_OGL |
 111              GEN6_CLIP_MODE_NORMAL |
 112              nonperspective_barycentric_enable_flag |
 113              GEN6_CLIP_XY_TEST |
 114              userclip << GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT |
 115              depth_clamp |
 116              provoking);
 117    OUT_BATCH(U_FIXED(0.125, 3) << GEN6_CLIP_MIN_POINT_WIDTH_SHIFT |
 118              U_FIXED(255.875, 3) << GEN6_CLIP_MAX_POINT_WIDTH_SHIFT |
 119              GEN6_CLIP_FORCE_ZERO_RTAINDEX);
 120    ADVANCE_BATCH();
 121 }
 122
 123 const struct brw_tracked_state gen6_clip_state = {
 124    .dirty = {
 125       .mesa  = _NEW_TRANSFORM | _NEW_LIGHT,
 126       .brw   = (BRW_NEW_CONTEXT |
 127                 BRW_NEW_FRAGMENT_PROGRAM |
 128                 BRW_NEW_HIZ),
 129       .cache = 0
 130    },
 131    .emit = upload_clip_state,
 132 };