src/gallium/drivers/llvmpipe/lp_setup_point.c

   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
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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_rast.h"
  37 #include "lp_state_fs.h"
  38 #include "tgsi/tgsi_scan.h"
  39
  40 #define NUM_CHANNELS 4
  41
  42 struct point_info {
  43    /* x,y deltas */
  44    int dy01, dy12;
  45    int dx01, dx12;
  46
  47    const float (*v0)[4];
  48 };
  49
  50
  51 /**
  52  * Compute a0 for a constant-valued coefficient (GL_FLAT shading).
  53  */
  54 static void
  55 constant_coef(struct lp_setup_context *setup,
  56               struct lp_rast_triangle *point,
  57               unsigned slot,
  58               const float value,
  59               unsigned i)
  60 {
  61    point->inputs.a0[slot][i] = value;
  62    point->inputs.dadx[slot][i] = 0.0f;
  63    point->inputs.dady[slot][i] = 0.0f;
  64 }
  65
  66
  67 static void
  68 point_persp_coeff(struct lp_setup_context *setup,
  69                   struct lp_rast_triangle *point,
  70                   const struct point_info *info,
  71                   unsigned slot,
  72                   unsigned i)
  73 {
  74    /*
  75     * Fragment shader expects pre-multiplied w for LP_INTERP_PERSPECTIVE. A
  76     * better stratergy would be to take the primitive in consideration when
  77     * generating the fragment shader key, and therefore avoid the per-fragment
  78     * perspective divide.
  79     */
  80
  81    float w0 = info->v0[0][3];
  82
  83    assert(i < 4);
  84
  85    point->inputs.a0[slot][i] = info->v0[slot][i]*w0;
  86    point->inputs.dadx[slot][i] = 0.0f;
  87    point->inputs.dady[slot][i] = 0.0f;
  88 }
  89
  90
  91 /**
  92  * Setup automatic texcoord coefficients (for sprite rendering).
  93  * \param slot  the vertex attribute slot to setup
  94  * \param i  the attribute channel in [0,3]
  95  * \param sprite_coord_origin  one of PIPE_SPRITE_COORD_x
  96  * \param perspective  does the shader expects pre-multiplied w, i.e.,
  97  *    LP_INTERP_PERSPECTIVE is specified in the shader key
  98  */
  99 static void
 100 texcoord_coef(struct lp_setup_context *setup,
 101               struct lp_rast_triangle *point,
 102               const struct point_info *info,
 103               unsigned slot,
 104               unsigned i,
 105               unsigned sprite_coord_origin,
 106               boolean perspective)
 107 {
 108    float w0 = info->v0[0][3];
 109
 110    assert(i < 4);
 111
 112    if (i == 0) {
 113       float dadx = FIXED_ONE / (float)info->dx12;
 114       float dady =  0.0f;
 115       float x0 = info->v0[0][0] - setup->pixel_offset;
 116       float y0 = info->v0[0][1] - setup->pixel_offset;
 117
 118       point->inputs.dadx[slot][0] = dadx;
 119       point->inputs.dady[slot][0] = dady;
 120       point->inputs.a0[slot][0] = 0.5 - (dadx * x0 + dady * y0);
 121
 122       if (perspective) {
 123          point->inputs.dadx[slot][0] *= w0;
 124          point->inputs.dady[slot][0] *= w0;
 125          point->inputs.a0[slot][0] *= w0;
 126       }
 127    }
 128    else if (i == 1) {
 129       float dadx = 0.0f;
 130       float dady = FIXED_ONE / (float)info->dx12;
 131       float x0 = info->v0[0][0] - setup->pixel_offset;
 132       float y0 = info->v0[0][1] - setup->pixel_offset;
 133
 134       if (sprite_coord_origin == PIPE_SPRITE_COORD_LOWER_LEFT) {
 135          dady = -dady;
 136       }
 137
 138       point->inputs.dadx[slot][1] = dadx;
 139       point->inputs.dady[slot][1] = dady;
 140       point->inputs.a0[slot][1] = 0.5 - (dadx * x0 + dady * y0);
 141
 142       if (perspective) {
 143          point->inputs.dadx[slot][1] *= w0;
 144          point->inputs.dady[slot][1] *= w0;
 145          point->inputs.a0[slot][1] *= w0;
 146       }
 147    }
 148    else if (i == 2) {
 149       point->inputs.a0[slot][2] = 0.0f;
 150       point->inputs.dadx[slot][2] = 0.0f;
 151       point->inputs.dady[slot][2] = 0.0f;
 152    }
 153    else {
 154       point->inputs.a0[slot][3] = perspective ? w0 : 1.0f;
 155       point->inputs.dadx[slot][3] = 0.0f;
 156       point->inputs.dady[slot][3] = 0.0f;
 157    }
 158 }
 159
 160
 161 /**
 162  * Special coefficient setup for gl_FragCoord.
 163  * X and Y are trivial
 164  * Z and W are copied from position_coef which should have already been computed.
 165  * We could do a bit less work if we'd examine gl_FragCoord's swizzle mask.
 166  */
 167 static void
 168 setup_point_fragcoord_coef(struct lp_setup_context *setup,
 169                            struct lp_rast_triangle *point,
 170                            const struct point_info *info,
 171                            unsigned slot,
 172                            unsigned usage_mask)
 173 {
 174    /*X*/
 175    if (usage_mask & TGSI_WRITEMASK_X) {
 176       point->inputs.a0[slot][0] = 0.0;
 177       point->inputs.dadx[slot][0] = 1.0;
 178       point->inputs.dady[slot][0] = 0.0;
 179    }
 180
 181    /*Y*/
 182    if (usage_mask & TGSI_WRITEMASK_Y) {
 183       point->inputs.a0[slot][1] = 0.0;
 184       point->inputs.dadx[slot][1] = 0.0;
 185       point->inputs.dady[slot][1] = 1.0;
 186    }
 187
 188    /*Z*/
 189    if (usage_mask & TGSI_WRITEMASK_Z) {
 190       constant_coef(setup, point, slot, info->v0[0][2], 2);
 191    }
 192
 193    /*W*/
 194    if (usage_mask & TGSI_WRITEMASK_W) {
 195       constant_coef(setup, point, slot, info->v0[0][3], 3);
 196    }
 197 }
 198
 199
 200 /**
 201  * Compute the point->coef[] array dadx, dady, a0 values.
 202  */
 203 static void
 204 setup_point_coefficients( struct lp_setup_context *setup,
 205                           struct lp_rast_triangle *point,
 206                           const struct point_info *info)
 207 {
 208    const struct lp_fragment_shader *shader = setup->fs.current.variant->shader;
 209    unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ;
 210    unsigned slot;
 211
 212    /* setup interpolation for all the remaining attributes:
 213     */
 214    for (slot = 0; slot < setup->fs.nr_inputs; slot++) {
 215       enum lp_interp interp = setup->fs.input[slot].interp;
 216       boolean perspective = !!(interp == LP_INTERP_PERSPECTIVE);
 217       unsigned vert_attr = setup->fs.input[slot].src_index;
 218       unsigned usage_mask = setup->fs.input[slot].usage_mask;
 219       unsigned i;
 220
 221       if (perspective & usage_mask) {
 222          fragcoord_usage_mask |= TGSI_WRITEMASK_W;
 223       }
 224
 225       switch (interp) {
 226       case LP_INTERP_POSITION:
 227          /*
 228           * The generated pixel interpolators will pick up the coeffs from
 229           * slot 0, so all need to ensure that the usage mask is covers all
 230           * usages.
 231           */
 232          fragcoord_usage_mask |= usage_mask;
 233          break;
 234
 235       case LP_INTERP_LINEAR:
 236          /* Sprite tex coords may use linear interpolation someday */
 237          /* fall-through */
 238       case LP_INTERP_PERSPECTIVE:
 239          /* check if the sprite coord flag is set for this attribute.
 240           * If so, set it up so it up so x and y vary from 0 to 1.
 241           */
 242          if (shader->info.base.input_semantic_name[slot] == TGSI_SEMANTIC_GENERIC) {
 243             unsigned semantic_index = shader->info.base.input_semantic_index[slot];
 244             /* Note that sprite_coord enable is a bitfield of
 245              * PIPE_MAX_SHADER_OUTPUTS bits.
 246              */
 247             if (semantic_index < PIPE_MAX_SHADER_OUTPUTS &&
 248                 (setup->sprite_coord_enable & (1 << semantic_index))) {
 249                for (i = 0; i < NUM_CHANNELS; i++) {
 250                   if (usage_mask & (1 << i)) {
 251                      texcoord_coef(setup, point, info, slot + 1, i,
 252                                    setup->sprite_coord_origin,
 253                                    perspective);
 254                   }
 255                }
 256                break;
 257             }
 258          }
 259          /* fall-through */
 260       case LP_INTERP_CONSTANT:
 261          for (i = 0; i < NUM_CHANNELS; i++) {
 262             if (usage_mask & (1 << i)) {
 263                if (perspective) {
 264                   point_persp_coeff(setup, point, info, slot+1, i);
 265                }
 266                else {
 267                   constant_coef(setup, point, slot+1, info->v0[vert_attr][i], i);
 268                }
 269             }
 270          }
 271          break;
 272
 273       case LP_INTERP_FACING:
 274          for (i = 0; i < NUM_CHANNELS; i++)
 275             if (usage_mask & (1 << i))
 276                constant_coef(setup, point, slot+1, 1.0, i);
 277          break;
 278
 279       default:
 280          assert(0);
 281          break;
 282       }
 283    }
 284
 285    /* The internal position input is in slot zero:
 286     */
 287    setup_point_fragcoord_coef(setup, point, info, 0,
 288                               fragcoord_usage_mask);
 289 }
 290
 291
 292 static INLINE int
 293 subpixel_snap(float a)
 294 {
 295    return util_iround(FIXED_ONE * a);
 296 }
 297
 298
 299 static boolean
 300 try_setup_point( struct lp_setup_context *setup,
 301                  const float (*v0)[4] )
 302 {
 303    /* x/y positions in fixed point */
 304    const int sizeAttr = setup->psize;
 305    const float size
 306       = (setup->point_size_per_vertex && sizeAttr > 0) ? v0[sizeAttr][0]
 307       : setup->point_size;
 308
 309    /* Point size as fixed point integer, remove rounding errors
 310     * and gives minimum width for very small points
 311     */
 312    int fixed_width = MAX2(FIXED_ONE,
 313                           (subpixel_snap(size) + FIXED_ONE/2 - 1) & ~(FIXED_ONE-1));
 314
 315    const int x0 = subpixel_snap(v0[0][0] - setup->pixel_offset) - fixed_width/2;
 316    const int y0 = subpixel_snap(v0[0][1] - setup->pixel_offset) - fixed_width/2;
 317
 318    struct lp_scene *scene = setup->scene;
 319    struct lp_rast_triangle *point;
 320    unsigned bytes;
 321    struct u_rect bbox;
 322    unsigned nr_planes = 4;
 323    struct point_info info;
 324
 325
 326    /* Bounding rectangle (in pixels) */
 327    {
 328       /* Yes this is necessary to accurately calculate bounding boxes
 329        * with the two fill-conventions we support.  GL (normally) ends
 330        * up needing a bottom-left fill convention, which requires
 331        * slightly different rounding.
 332        */
 333       int adj = (setup->pixel_offset != 0) ? 1 : 0;
 334
 335       bbox.x0 = (x0 + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 336       bbox.x1 = (x0 + fixed_width + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 337       bbox.y0 = (y0 + (FIXED_ONE-1)) >> FIXED_ORDER;
 338       bbox.y1 = (y0 + fixed_width + (FIXED_ONE-1)) >> FIXED_ORDER;
 339
 340       /* Inclusive coordinates:
 341        */
 342       bbox.x1--;
 343       bbox.y1--;
 344    }
 345
 346    if (!u_rect_test_intersection(&setup->draw_region, &bbox)) {
 347       if (0) debug_printf("offscreen\n");
 348       LP_COUNT(nr_culled_tris);
 349       return TRUE;
 350    }
 351
 352    u_rect_find_intersection(&setup->draw_region, &bbox);
 353
 354    point = lp_setup_alloc_triangle(scene,
 355                                    setup->fs.nr_inputs,
 356                                    nr_planes,
 357                                    &bytes);
 358    if (!point)
 359       return FALSE;
 360
 361 #ifdef DEBUG
 362    point->v[0][0] = v0[0][0];
 363    point->v[0][1] = v0[0][1];
 364 #endif
 365
 366    info.v0 = v0;
 367    info.dx01 = 0;
 368    info.dx12 = fixed_width;
 369    info.dy01 = fixed_width;
 370    info.dy12 = 0;
 371
 372    /* Setup parameter interpolants:
 373     */
 374    setup_point_coefficients(setup, point, &info);
 375
 376    point->inputs.facing = 1.0F;
 377    point->inputs.state = setup->fs.stored;
 378    point->inputs.disable = FALSE;
 379    point->inputs.opaque = FALSE;
 380
 381    {
 382       point->plane[0].dcdx = -1;
 383       point->plane[0].dcdy = 0;
 384       point->plane[0].c = 1-bbox.x0;
 385       point->plane[0].ei = 0;
 386       point->plane[0].eo = 1;
 387
 388       point->plane[1].dcdx = 1;
 389       point->plane[1].dcdy = 0;
 390       point->plane[1].c = bbox.x1+1;
 391       point->plane[1].ei = -1;
 392       point->plane[1].eo = 0;
 393
 394       point->plane[2].dcdx = 0;
 395       point->plane[2].dcdy = 1;
 396       point->plane[2].c = 1-bbox.y0;
 397       point->plane[2].ei = 0;
 398       point->plane[2].eo = 1;
 399
 400       point->plane[3].dcdx = 0;
 401       point->plane[3].dcdy = -1;
 402       point->plane[3].c = bbox.y1+1;
 403       point->plane[3].ei = -1;
 404       point->plane[3].eo = 0;
 405    }
 406
 407    return lp_setup_bin_triangle(setup, point, &bbox, nr_planes);
 408 }
 409
 410
 411 static void
 412 lp_setup_point(struct lp_setup_context *setup,
 413                const float (*v0)[4])
 414 {
 415    if (!try_setup_point( setup, v0 ))
 416    {
 417       if (!lp_setup_flush_and_restart(setup))
 418          return;
 419
 420       if (!try_setup_point( setup, v0 ))
 421          return;
 422    }
 423 }
 424
 425
 426 void
 427 lp_setup_choose_point( struct lp_setup_context *setup )
 428 {
 429    setup->point = lp_setup_point;
 430 }
 431
 432