src/gallium/auxiliary/draw/draw_cliptest_tmp.h

   1 /**************************************************************************
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   3  * Copyright 2010, VMware, inc.
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  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_clipdistance_output(pvs->draw, 0);
  53    cd[1] = draw_current_shader_clipdistance_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          /* Do the hardwired planes first:
  98           */
  99          if (flags & DO_CLIP_XY_GUARD_BAND) {
 100             if (-0.50 * position[0] + position[3] < 0) mask |= (1<<0);
 101             if ( 0.50 * position[0] + position[3] < 0) mask |= (1<<1);
 102             if (-0.50 * position[1] + position[3] < 0) mask |= (1<<2);
 103             if ( 0.50 * position[1] + position[3] < 0) mask |= (1<<3);
 104          }
 105          else if (flags & DO_CLIP_XY) {
 106             if (-position[0] + position[3] < 0) mask |= (1<<0);
 107             if ( position[0] + position[3] < 0) mask |= (1<<1);
 108             if (-position[1] + position[3] < 0) mask |= (1<<2);
 109             if ( position[1] + position[3] < 0) mask |= (1<<3);
 110          }
 111
 112          /* Clip Z planes according to full cube, half cube or none.
 113           */
 114          if (flags & DO_CLIP_FULL_Z) {
 115             if ( position[2] + position[3] < 0) mask |= (1<<4);
 116             if (-position[2] + position[3] < 0) mask |= (1<<5);
 117          }
 118          else if (flags & DO_CLIP_HALF_Z) {
 119             if ( position[2]               < 0) mask |= (1<<4);
 120             if (-position[2] + position[3] < 0) mask |= (1<<5);
 121          }
 122
 123          if (flags & DO_CLIP_USER) {
 124             unsigned ucp_mask = ucp_enable;
 125
 126             while (ucp_mask) {
 127                unsigned plane_idx = ffs(ucp_mask)-1;
 128                ucp_mask &= ~(1 << plane_idx);
 129                plane_idx += 6;
 130
 131                /*
 132                 * for user clipping check if we have a clip distance output
 133                 * and the shader has written to it, otherwise use clipvertex
 134                 * to decide when the plane is clipping.
 135                 */
 136                if (have_cd && num_written_clipdistance) {
 137                   float clipdist;
 138                   i = plane_idx - 6;
 139                   /* first four clip distance in first vector etc. */
 140                   if (i < 4)
 141                      clipdist = out->data[cd[0]][i];
 142                   else
 143                      clipdist = out->data[cd[1]][i-4];
 144                   if (clipdist < 0 || util_is_inf_or_nan(clipdist))
 145                      mask |= 1 << plane_idx;
 146                } else {
 147                   if (dot4(clipvertex, plane[plane_idx]) < 0)
 148                      mask |= 1 << plane_idx;
 149                }
 150             }
 151          }
 152
 153          out->clipmask = mask;
 154          need_pipeline |= out->clipmask;
 155       }
 156
 157       /*
 158        * Transform the vertex position from clip coords to window coords,
 159        * if the vertex is unclipped.
 160        */
 161       if ((flags & DO_VIEWPORT) && mask == 0)
 162       {
 163          /* divide by w */
 164          float w = 1.0f / position[3];
 165
 166          /* Viewport mapping */
 167          position[0] = position[0] * w * scale[0] + trans[0];
 168          position[1] = position[1] * w * scale[1] + trans[1];
 169          position[2] = position[2] * w * scale[2] + trans[2];
 170          position[3] = w;
 171       }
 172 #ifdef DEBUG
 173       /* For debug builds, set the clipped vertex's window coordinate
 174        * to NaN to help catch potential errors later.
 175        */
 176       else {
 177          float zero = 0.0f;
 178          position[0] =
 179          position[1] =
 180          position[2] =
 181          position[3] = zero / zero; /* MSVC doesn't accept 0.0 / 0.0 */
 182       }
 183 #endif
 184
 185       if ((flags & DO_EDGEFLAG) && ef) {
 186          const float *edgeflag = out->data[ef];
 187          out->edgeflag = !(edgeflag[0] != 1.0f);
 188          need_pipeline |= !out->edgeflag;
 189       }
 190
 191       out = (struct vertex_header *)( (char *)out + info->stride );
 192    }
 193
 194    return need_pipeline != 0;
 195 }
 196
 197
 198 #undef FLAGS
 199 #undef TAG