src/gallium/drivers/llvmpipe/lp_setup_point.c

   1 /**************************************************************************
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   3  * Copyright 2010, VMware Inc.
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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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  26  **************************************************************************/
  27
  28 /*
  29  * Binning code for points
  30  */
  31
  32 #include "lp_setup_context.h"
  33 #include "util/u_math.h"
  34 #include "util/u_memory.h"
  35 #include "lp_perf.h"
  36 #include "lp_setup_context.h"
  37 #include "lp_rast.h"
  38 #include "lp_state_fs.h"
  39 #include "tgsi/tgsi_scan.h"
  40
  41 #define NUM_CHANNELS 4
  42
  43 struct point_info {
  44    /* x,y deltas */
  45    int dy01, dy12;
  46    int dx01, dx12;
  47
  48    const float (*v0)[4];
  49 };
  50
  51
  52 /**
  53  * Compute a0 for a constant-valued coefficient (GL_FLAT shading).
  54  */
  55 static void
  56 constant_coef(struct lp_setup_context *setup,
  57               struct lp_rast_triangle *point,
  58               unsigned slot,
  59               const float value,
  60               unsigned i)
  61 {
  62    point->inputs.a0[slot][i] = value;
  63    point->inputs.dadx[slot][i] = 0.0f;
  64    point->inputs.dady[slot][i] = 0.0f;
  65 }
  66
  67
  68 static void
  69 perspective_coef(struct lp_setup_context *setup,
  70                  struct lp_rast_triangle *point,
  71                  const struct point_info *info,
  72                  unsigned slot,
  73                  unsigned vert_attr,
  74                  unsigned i,
  75                  unsigned sprite_coord_origin)
  76 {
  77    if (i == 0) {
  78       float dadx = FIXED_ONE / (float)info->dx12;
  79       float dady =  0.0f;
  80       point->inputs.dadx[slot][i] = dadx;
  81       point->inputs.dady[slot][i] = dady;
  82       point->inputs.a0[slot][i] = (0.5 -
  83                                   (dadx * ((float)info->v0[0][0] - setup->pixel_offset) +
  84                                    dady * ((float)info->v0[0][1] - setup->pixel_offset)));
  85    }
  86    else if (i == 1) {
  87       float dadx = 0.0f;
  88       float dady = FIXED_ONE / (float)info->dx12;
  89
  90       if (sprite_coord_origin == PIPE_SPRITE_COORD_LOWER_LEFT) {
  91          dady = -dady;
  92       }
  93
  94       point->inputs.dadx[slot][i] = dadx;
  95       point->inputs.dady[slot][i] = dady;
  96       point->inputs.a0[slot][i] = (0.5 -
  97                                    (dadx * ((float)info->v0[0][0] - setup->pixel_offset) +
  98                                     dady * ((float)info->v0[0][1] - setup->pixel_offset)));
  99    }
 100    else if (i == 2) {
 101       point->inputs.a0[slot][i] = 0.0f;
 102       point->inputs.dadx[slot][i] = 0.0f;
 103       point->inputs.dady[slot][i] = 0.0f;
 104    }
 105    else if (i == 3) {
 106       point->inputs.a0[slot][i] = 1.0f;
 107       point->inputs.dadx[slot][i] = 0.0f;
 108       point->inputs.dady[slot][i] = 0.0f;
 109    }
 110 }
 111
 112
 113 /**
 114  * Special coefficient setup for gl_FragCoord.
 115  * X and Y are trivial
 116  * Z and W are copied from position_coef which should have already been computed.
 117  * We could do a bit less work if we'd examine gl_FragCoord's swizzle mask.
 118  */
 119 static void
 120 setup_point_fragcoord_coef(struct lp_setup_context *setup,
 121                            struct lp_rast_triangle *point,
 122                            const struct point_info *info,
 123                            unsigned slot,
 124                            unsigned usage_mask)
 125 {
 126    /*X*/
 127    if (usage_mask & TGSI_WRITEMASK_X) {
 128       point->inputs.a0[slot][0] = 0.0;
 129       point->inputs.dadx[slot][0] = 1.0;
 130       point->inputs.dady[slot][0] = 0.0;
 131    }
 132
 133    /*Y*/
 134    if (usage_mask & TGSI_WRITEMASK_Y) {
 135       point->inputs.a0[slot][1] = 0.0;
 136       point->inputs.dadx[slot][1] = 0.0;
 137       point->inputs.dady[slot][1] = 1.0;
 138    }
 139
 140    /*Z*/
 141    if (usage_mask & TGSI_WRITEMASK_Z) {
 142       constant_coef(setup, point, slot, info->v0[0][2], 2);
 143    }
 144
 145    /*W*/
 146    if (usage_mask & TGSI_WRITEMASK_W) {
 147       constant_coef(setup, point, slot, info->v0[0][3], 3);
 148    }
 149 }
 150
 151
 152 /**
 153  * Compute the point->coef[] array dadx, dady, a0 values.
 154  */
 155 static void
 156 setup_point_coefficients( struct lp_setup_context *setup,
 157                           struct lp_rast_triangle *point,
 158                           const struct point_info *info)
 159 {
 160    const struct lp_fragment_shader *shader = setup->fs.current.variant->shader;
 161    unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ;
 162    unsigned slot;
 163
 164    /* setup interpolation for all the remaining attributes:
 165     */
 166    for (slot = 0; slot < setup->fs.nr_inputs; slot++) {
 167       unsigned vert_attr = setup->fs.input[slot].src_index;
 168       unsigned usage_mask = setup->fs.input[slot].usage_mask;
 169       unsigned i;
 170
 171       switch (setup->fs.input[slot].interp) {
 172       case LP_INTERP_POSITION:
 173          /*
 174           * The generated pixel interpolators will pick up the coeffs from
 175           * slot 0, so all need to ensure that the usage mask is covers all
 176           * usages.
 177           */
 178          fragcoord_usage_mask |= usage_mask;
 179          break;
 180
 181       case LP_INTERP_LINEAR:
 182          /* Sprite tex coords may use linear interpolation someday */
 183          /* fall-through */
 184
 185       case LP_INTERP_PERSPECTIVE:
 186          /* check if the sprite coord flag is set for this attribute.
 187           * If so, set it up so it up so x any y vary from 0 to 1.
 188           */
 189          if (shader->info.input_semantic_name[slot] == TGSI_SEMANTIC_GENERIC) {
 190             const int index = shader->info.input_semantic_index[slot];
 191
 192             if (setup->sprite_coord_enable & (1 << index)) {
 193                for (i = 0; i < NUM_CHANNELS; i++)
 194                   if (usage_mask & (1 << i))
 195                      perspective_coef(setup, point, info, slot+1, vert_attr, i,
 196                                       setup->sprite_coord_origin);
 197                fragcoord_usage_mask |= TGSI_WRITEMASK_W;
 198                break;
 199             }
 200          }
 201
 202          /* Otherwise fallthrough */
 203       default:
 204          for (i = 0; i < NUM_CHANNELS; i++) {
 205             if (usage_mask & (1 << i))
 206                constant_coef(setup, point, slot+1, info->v0[vert_attr][i], i);
 207          }
 208       }
 209    }
 210
 211    /* The internal position input is in slot zero:
 212     */
 213    setup_point_fragcoord_coef(setup, point, info, 0,
 214                               fragcoord_usage_mask);
 215 }
 216
 217
 218 static INLINE int
 219 subpixel_snap(float a)
 220 {
 221    return util_iround(FIXED_ONE * a);
 222 }
 223
 224
 225 static boolean
 226 try_setup_point( struct lp_setup_context *setup,
 227                  const float (*v0)[4] )
 228 {
 229    /* x/y positions in fixed point */
 230    const int sizeAttr = setup->psize;
 231    const float size
 232       = (setup->point_size_per_vertex && sizeAttr > 0) ? v0[sizeAttr][0]
 233       : setup->point_size;
 234
 235    /* Point size as fixed point integer, remove rounding errors
 236     * and gives minimum width for very small points
 237     */
 238    int fixed_width = MAX2(FIXED_ONE,
 239                           (subpixel_snap(size) + FIXED_ONE/2 - 1) & ~(FIXED_ONE-1));
 240
 241    const int x0 = subpixel_snap(v0[0][0] - setup->pixel_offset) - fixed_width/2;
 242    const int y0 = subpixel_snap(v0[0][1] - setup->pixel_offset) - fixed_width/2;
 243
 244    struct lp_scene *scene = setup->scene;
 245    struct lp_rast_triangle *point;
 246    unsigned bytes;
 247    struct u_rect bbox;
 248    unsigned nr_planes = 4;
 249    struct point_info info;
 250
 251
 252    /* Bounding rectangle (in pixels) */
 253    {
 254       /* Yes this is necessary to accurately calculate bounding boxes
 255        * with the two fill-conventions we support.  GL (normally) ends
 256        * up needing a bottom-left fill convention, which requires
 257        * slightly different rounding.
 258        */
 259       int adj = (setup->pixel_offset != 0) ? 1 : 0;
 260
 261       bbox.x0 = (x0 + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 262       bbox.x1 = (x0 + fixed_width + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 263       bbox.y0 = (y0 + (FIXED_ONE-1)) >> FIXED_ORDER;
 264       bbox.y1 = (y0 + fixed_width + (FIXED_ONE-1)) >> FIXED_ORDER;
 265
 266       /* Inclusive coordinates:
 267        */
 268       bbox.x1--;
 269       bbox.y1--;
 270    }
 271
 272    if (!u_rect_test_intersection(&setup->draw_region, &bbox)) {
 273       if (0) debug_printf("offscreen\n");
 274       LP_COUNT(nr_culled_tris);
 275       return TRUE;
 276    }
 277
 278    u_rect_find_intersection(&setup->draw_region, &bbox);
 279
 280    point = lp_setup_alloc_triangle(scene,
 281                                    setup->fs.nr_inputs,
 282                                    nr_planes,
 283                                    &bytes);
 284    if (!point)
 285       return FALSE;
 286
 287 #ifdef DEBUG
 288    point->v[0][0] = v0[0][0];
 289    point->v[0][1] = v0[0][1];
 290 #endif
 291
 292    info.v0 = v0;
 293    info.dx01 = 0;
 294    info.dx12 = fixed_width;
 295    info.dy01 = fixed_width;
 296    info.dy12 = 0;
 297
 298    /* Setup parameter interpolants:
 299     */
 300    setup_point_coefficients(setup, point, &info);
 301
 302    point->inputs.facing = 1.0F;
 303    point->inputs.state = setup->fs.stored;
 304    point->inputs.disable = FALSE;
 305    point->inputs.opaque = FALSE;
 306
 307    {
 308       point->plane[0].dcdx = -1;
 309       point->plane[0].dcdy = 0;
 310       point->plane[0].c = 1-bbox.x0;
 311       point->plane[0].ei = 0;
 312       point->plane[0].eo = 1;
 313
 314       point->plane[1].dcdx = 1;
 315       point->plane[1].dcdy = 0;
 316       point->plane[1].c = bbox.x1+1;
 317       point->plane[1].ei = -1;
 318       point->plane[1].eo = 0;
 319
 320       point->plane[2].dcdx = 0;
 321       point->plane[2].dcdy = 1;
 322       point->plane[2].c = 1-bbox.y0;
 323       point->plane[2].ei = 0;
 324       point->plane[2].eo = 1;
 325
 326       point->plane[3].dcdx = 0;
 327       point->plane[3].dcdy = -1;
 328       point->plane[3].c = bbox.y1+1;
 329       point->plane[3].ei = -1;
 330       point->plane[3].eo = 0;
 331    }
 332
 333    return lp_setup_bin_triangle(setup, point, &bbox, nr_planes);
 334 }
 335
 336
 337 static void
 338 lp_setup_point(struct lp_setup_context *setup,
 339                const float (*v0)[4])
 340 {
 341    if (!try_setup_point( setup, v0 ))
 342    {
 343       lp_setup_flush_and_restart(setup);
 344
 345       if (!try_setup_point( setup, v0 ))
 346          assert(0);
 347    }
 348 }
 349
 350
 351 void
 352 lp_setup_choose_point( struct lp_setup_context *setup )
 353 {
 354    setup->point = lp_setup_point;
 355 }
 356
 357