src/gallium/auxiliary/draw/draw_cliptest_tmp.h

   1 /**************************************************************************
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   3  * Copyright 2010, VMware, inc.
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   7  * copy of this software and associated documentation files (the
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  11  * permit persons to whom the Software is furnished to do so, subject to
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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  25  *
  26  **************************************************************************/
  27
  28 static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
  29                                  struct draw_vertex_info *info,
  30                                  const struct draw_prim_info *prim_info )
  31 {
  32    struct vertex_header *out = info->verts;
  33    /* const */ float (*plane)[4] = pvs->draw->plane;
  34    const unsigned pos = draw_current_shader_position_output(pvs->draw);
  35    const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
  36    unsigned cd[2];
  37    const unsigned ef = pvs->draw->vs.edgeflag_output;
  38    unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
  39    unsigned flags = (FLAGS);
  40    unsigned need_pipeline = 0;
  41    unsigned j;
  42    unsigned i;
  43    bool have_cd = false;
  44    unsigned viewport_index_output =
  45       draw_current_shader_viewport_index_output(pvs->draw);
  46    int viewport_index =
  47       draw_current_shader_uses_viewport_index(pvs->draw) ?
  48       *((unsigned*)out->data[viewport_index_output]): 0;
  49    int num_written_clipdistance =
  50       draw_current_shader_num_written_clipdistances(pvs->draw);
  51
  52    cd[0] = draw_current_shader_ccdistance_output(pvs->draw, 0);
  53    cd[1] = draw_current_shader_ccdistance_output(pvs->draw, 1);
  54
  55    if (cd[0] != pos || cd[1] != pos)
  56       have_cd = true;
  57
  58    /* If clipdistance semantic has been written by the shader
  59     * that means we're expected to do 'user plane clipping' */
  60    if (num_written_clipdistance && !(flags & DO_CLIP_USER)) {
  61       flags |= DO_CLIP_USER;
  62       ucp_enable = (1 << num_written_clipdistance) - 1;
  63    }
  64
  65    assert(pos != -1);
  66    for (j = 0; j < info->count; j++) {
  67       float *position = out->data[pos];
  68       unsigned mask = 0x0;
  69       float *scale = pvs->draw->viewports[0].scale;
  70       float *trans = pvs->draw->viewports[0].translate;
  71       if (draw_current_shader_uses_viewport_index(pvs->draw)) {
  72          unsigned verts_per_prim = u_vertices_per_prim(prim_info->prim);
  73          /* only change the viewport_index for the leading vertex */
  74          if (!(j % verts_per_prim)) {
  75             viewport_index = *((unsigned*)out->data[viewport_index_output]);
  76             viewport_index = draw_clamp_viewport_idx(viewport_index);
  77          }
  78          scale = pvs->draw->viewports[viewport_index].scale;
  79          trans = pvs->draw->viewports[viewport_index].translate;
  80       }
  81
  82       initialize_vertex_header(out);
  83
  84       if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
  85                    DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
  86          float *clipvertex = position;
  87
  88          if ((flags & DO_CLIP_USER) && cv != pos) {
  89             assert(cv != -1);
  90             clipvertex = out->data[cv];
  91          }
  92
  93          for (i = 0; i < 4; i++) {
  94             out->clip_pos[i] = position[i];
  95          }
  96
  97          /* Be careful with NaNs. Comparisons must be true for them. */
  98          /* Do the hardwired planes first:
  99           */
 100          if (flags & DO_CLIP_XY_GUARD_BAND) {
 101             if (!(-0.50 * position[0] + position[3] >= 0)) mask |= (1<<0);
 102             if (!( 0.50 * position[0] + position[3] >= 0)) mask |= (1<<1);
 103             if (!(-0.50 * position[1] + position[3] >= 0)) mask |= (1<<2);
 104             if (!( 0.50 * position[1] + position[3] >= 0)) mask |= (1<<3);
 105          }
 106          else if (flags & DO_CLIP_XY) {
 107             if (!(-position[0] + position[3] >= 0)) mask |= (1<<0);
 108             if (!( position[0] + position[3] >= 0)) mask |= (1<<1);
 109             if (!(-position[1] + position[3] >= 0)) mask |= (1<<2);
 110             if (!( position[1] + position[3] >= 0)) mask |= (1<<3);
 111          }
 112
 113          /* Clip Z planes according to full cube, half cube or none.
 114           */
 115          if (flags & DO_CLIP_FULL_Z) {
 116             if (!( position[2] + position[3] >= 0)) mask |= (1<<4);
 117             if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
 118          }
 119          else if (flags & DO_CLIP_HALF_Z) {
 120             if (!( position[2]               >= 0)) mask |= (1<<4);
 121             if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
 122          }
 123
 124          if (flags & DO_CLIP_USER) {
 125             unsigned ucp_mask = ucp_enable;
 126
 127             while (ucp_mask) {
 128                unsigned plane_idx = ffs(ucp_mask)-1;
 129                ucp_mask &= ~(1 << plane_idx);
 130                plane_idx += 6;
 131
 132                /*
 133                 * for user clipping check if we have a clip distance output
 134                 * and the shader has written to it, otherwise use clipvertex
 135                 * to decide when the plane is clipping.
 136                 */
 137                if (have_cd && num_written_clipdistance) {
 138                   float clipdist;
 139                   i = plane_idx - 6;
 140                   /* first four clip distance in first vector etc. */
 141                   if (i < 4)
 142                      clipdist = out->data[cd[0]][i];
 143                   else
 144                      clipdist = out->data[cd[1]][i-4];
 145                   if (clipdist < 0 || util_is_inf_or_nan(clipdist))
 146                      mask |= 1 << plane_idx;
 147                } else {
 148                   if (!(dot4(clipvertex, plane[plane_idx]) >= 0))
 149                      mask |= 1 << plane_idx;
 150                }
 151             }
 152          }
 153
 154          out->clipmask = mask;
 155          need_pipeline |= out->clipmask;
 156       }
 157
 158       /*
 159        * Transform the vertex position from clip coords to window coords,
 160        * if the vertex is unclipped.
 161        */
 162       if ((flags & DO_VIEWPORT) && mask == 0)
 163       {
 164          /* divide by w */
 165          float w = 1.0f / position[3];
 166
 167          /* Viewport mapping */
 168          position[0] = position[0] * w * scale[0] + trans[0];
 169          position[1] = position[1] * w * scale[1] + trans[1];
 170          position[2] = position[2] * w * scale[2] + trans[2];
 171          position[3] = w;
 172       }
 173 #ifdef DEBUG
 174       /* For debug builds, set the clipped vertex's window coordinate
 175        * to NaN to help catch potential errors later.
 176        */
 177       else {
 178          float zero = 0.0f;
 179          position[0] =
 180          position[1] =
 181          position[2] =
 182          position[3] = zero / zero; /* MSVC doesn't accept 0.0 / 0.0 */
 183       }
 184 #endif
 185
 186       if ((flags & DO_EDGEFLAG) && ef) {
 187          const float *edgeflag = out->data[ef];
 188          out->edgeflag = !(edgeflag[0] != 1.0f);
 189          need_pipeline |= !out->edgeflag;
 190       }
 191
 192       out = (struct vertex_header *)( (char *)out + info->stride );
 193    }
 194    return need_pipeline != 0;
 195 }
 196
 197
 198 #undef FLAGS
 199 #undef TAG