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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  13  *
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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  25  *
  26  **************************************************************************/
  27
  28 #include "util/u_bitcast.h"
  29
  30 static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
  31                                  struct draw_vertex_info *info,
  32                                  const struct draw_prim_info *prim_info )
  33 {
  34    struct vertex_header *out = info->verts;
  35    /* const */ float (*plane)[4] = pvs->draw->plane;
  36    const unsigned pos = draw_current_shader_position_output(pvs->draw);
  37    const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
  38    unsigned cd[2];
  39    const unsigned ef = pvs->draw->vs.edgeflag_output;
  40    unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
  41    unsigned flags = (FLAGS);
  42    unsigned need_pipeline = 0;
  43    unsigned j;
  44    unsigned i;
  45    bool have_cd = false;
  46    bool uses_vp_idx = draw_current_shader_uses_viewport_index(pvs->draw);
  47    unsigned viewport_index_output =
  48       draw_current_shader_viewport_index_output(pvs->draw);
  49    int viewport_index = 0;
  50    int num_written_clipdistance =
  51       draw_current_shader_num_written_clipdistances(pvs->draw);
  52
  53    if (uses_vp_idx) {
  54       viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
  55       viewport_index = draw_clamp_viewport_idx(viewport_index);
  56    }
  57
  58    cd[0] = draw_current_shader_ccdistance_output(pvs->draw, 0);
  59    cd[1] = draw_current_shader_ccdistance_output(pvs->draw, 1);
  60
  61    if (cd[0] != pos || cd[1] != pos)
  62       have_cd = true;
  63
  64    /* If clipdistance semantic has been written by the shader
  65     * that means we're expected to do 'user plane clipping' */
  66    if (num_written_clipdistance && !(flags & DO_CLIP_USER)) {
  67       flags |= DO_CLIP_USER;
  68       ucp_enable = (1 << num_written_clipdistance) - 1;
  69    }
  70
  71    assert(pos != -1);
  72    unsigned prim_idx = 0, prim_vert_idx = 0;
  73    for (j = 0; j < info->count; j++) {
  74       float *position = out->data[pos];
  75       unsigned mask = 0x0;
  76
  77       if (uses_vp_idx) {
  78          /* only change the viewport_index for the leading vertex */
  79          if (prim_vert_idx == (prim_info->primitive_lengths[prim_idx])) {
  80             prim_idx++;
  81             prim_vert_idx = 0;
  82             viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
  83             viewport_index = draw_clamp_viewport_idx(viewport_index);
  84          }
  85          prim_vert_idx++;
  86       }
  87       float *scale = pvs->draw->viewports[viewport_index].scale;
  88       float *trans = pvs->draw->viewports[viewport_index].translate;
  89       initialize_vertex_header(out);
  90
  91       if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
  92                    DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
  93          float *clipvertex = position;
  94
  95          if ((flags & DO_CLIP_USER) && cv != pos) {
  96             assert(cv != -1);
  97             clipvertex = out->data[cv];
  98          }
  99
 100          for (i = 0; i < 4; i++) {
 101             out->clip_pos[i] = position[i];
 102          }
 103
 104          /* Be careful with NaNs. Comparisons must be true for them. */
 105          /* Do the hardwired planes first:
 106           */
 107          if (flags & DO_CLIP_XY_GUARD_BAND) {
 108             if (!(-0.50 * position[0] + position[3] >= 0)) mask |= (1<<0);
 109             if (!( 0.50 * position[0] + position[3] >= 0)) mask |= (1<<1);
 110             if (!(-0.50 * position[1] + position[3] >= 0)) mask |= (1<<2);
 111             if (!( 0.50 * position[1] + position[3] >= 0)) mask |= (1<<3);
 112          }
 113          else if (flags & DO_CLIP_XY) {
 114             if (!(-position[0] + position[3] >= 0)) mask |= (1<<0);
 115             if (!( position[0] + position[3] >= 0)) mask |= (1<<1);
 116             if (!(-position[1] + position[3] >= 0)) mask |= (1<<2);
 117             if (!( position[1] + position[3] >= 0)) mask |= (1<<3);
 118          }
 119
 120          /* Clip Z planes according to full cube, half cube or none.
 121           */
 122          if (flags & DO_CLIP_FULL_Z) {
 123             if (!( position[2] + position[3] >= 0)) mask |= (1<<4);
 124             if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
 125          }
 126          else if (flags & DO_CLIP_HALF_Z) {
 127             if (!( position[2]               >= 0)) mask |= (1<<4);
 128             if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
 129          }
 130
 131          if (flags & DO_CLIP_USER) {
 132             unsigned ucp_mask = ucp_enable;
 133
 134             while (ucp_mask) {
 135                unsigned plane_idx = ffs(ucp_mask)-1;
 136                ucp_mask &= ~(1 << plane_idx);
 137                plane_idx += 6;
 138
 139                /*
 140                 * for user clipping check if we have a clip distance output
 141                 * and the shader has written to it, otherwise use clipvertex
 142                 * to decide when the plane is clipping.
 143                 */
 144                if (have_cd && num_written_clipdistance) {
 145                   float clipdist;
 146                   i = plane_idx - 6;
 147                   /* first four clip distance in first vector etc. */
 148                   if (i < 4)
 149                      clipdist = out->data[cd[0]][i];
 150                   else
 151                      clipdist = out->data[cd[1]][i-4];
 152                   if (clipdist < 0 || util_is_inf_or_nan(clipdist))
 153                      mask |= 1 << plane_idx;
 154                } else {
 155                   if (!(dot4(clipvertex, plane[plane_idx]) >= 0))
 156                      mask |= 1 << plane_idx;
 157                }
 158             }
 159          }
 160
 161          out->clipmask = mask;
 162          need_pipeline |= out->clipmask;
 163       }
 164
 165       /*
 166        * Transform the vertex position from clip coords to window coords,
 167        * if the vertex is unclipped.
 168        */
 169       if ((flags & DO_VIEWPORT) && mask == 0)
 170       {
 171          /* divide by w */
 172          float w = 1.0f / position[3];
 173
 174          /* Viewport mapping */
 175          position[0] = position[0] * w * scale[0] + trans[0];
 176          position[1] = position[1] * w * scale[1] + trans[1];
 177          position[2] = position[2] * w * scale[2] + trans[2];
 178          position[3] = w;
 179       }
 180 #ifdef DEBUG
 181       /* For debug builds, set the clipped vertex's window coordinate
 182        * to NaN to help catch potential errors later.
 183        */
 184       else {
 185          float zero = 0.0f;
 186          position[0] =
 187          position[1] =
 188          position[2] =
 189          position[3] = zero / zero; /* MSVC doesn't accept 0.0 / 0.0 */
 190       }
 191 #endif
 192
 193       if ((flags & DO_EDGEFLAG) && ef) {
 194          const float *edgeflag = out->data[ef];
 195          out->edgeflag = !(edgeflag[0] != 1.0f);
 196          need_pipeline |= !out->edgeflag;
 197       }
 198
 199       out = (struct vertex_header *)( (char *)out + info->stride );
 200    }
 201    return need_pipeline != 0;
 202 }
 203
 204
 205 #undef FLAGS
 206 #undef TAG