src/mesa/swrast/s_points.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "main/glheader.h"
  27 #include "main/colormac.h"
  28 #include "main/context.h"
  29 #include "main/macros.h"
  30 #include "main/texstate.h"
  31 #include "s_context.h"
  32 #include "s_feedback.h"
  33 #include "s_points.h"
  34 #include "s_span.h"
  35
  36
  37 /**
  38  * Used to cull points with invalid coords
  39  */
  40 #define CULL_INVALID(V)                              \
  41    do {                                              \
  42       float tmp = (V)->attrib[FRAG_ATTRIB_WPOS][0]   \
  43                 + (V)->attrib[FRAG_ATTRIB_WPOS][1];  \
  44       if (IS_INF_OR_NAN(tmp))                        \
  45          return;                                     \
  46    } while(0)
  47
  48
  49
  50 /**
  51  * Get/compute the point size.
  52  * The size may come from a vertex shader, or computed with attentuation
  53  * or just the glPointSize value.
  54  * Must also clamp to user-defined range and implmentation limits.
  55  */
  56 static INLINE GLfloat
  57 get_size(const GLcontext *ctx, const SWvertex *vert, GLboolean smoothed)
  58 {
  59    GLfloat size;
  60
  61    if (ctx->Point._Attenuated || ctx->VertexProgram.PointSizeEnabled) {
  62       /* use vertex's point size */
  63       size = vert->pointSize;
  64    }
  65    else {
  66       /* use constant point size */
  67       size = ctx->Point.Size;
  68    }
  69    /* always clamp to user-specified limits */
  70    size = CLAMP(size, ctx->Point.MinSize, ctx->Point.MaxSize);
  71    /* clamp to implementation limits */
  72    if (smoothed)
  73       size = CLAMP(size, ctx->Const.MinPointSizeAA, ctx->Const.MaxPointSizeAA);
  74    else
  75       size = CLAMP(size, ctx->Const.MinPointSize, ctx->Const.MaxPointSize);
  76
  77    return size;
  78 }
  79
  80
  81 /**
  82  * Draw a point sprite
  83  */
  84 static void
  85 sprite_point(GLcontext *ctx, const SWvertex *vert)
  86 {
  87    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  88    SWspan span;
  89    GLfloat size;
  90    GLuint tCoords[MAX_TEXTURE_COORD_UNITS + 1];
  91    GLuint numTcoords = 0;
  92    GLfloat t0, dtdy;
  93
  94    CULL_INVALID(vert);
  95
  96    /* z coord */
  97    if (ctx->DrawBuffer->Visual.depthBits <= 16)
  98       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
  99    else
 100       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 101    span.zStep = 0;
 102
 103    size = get_size(ctx, vert, GL_FALSE);
 104
 105    /* span init */
 106    INIT_SPAN(span, GL_POINT);
 107    span.interpMask = SPAN_Z | SPAN_RGBA;
 108
 109    span.facing = swrast->PointLineFacing;
 110
 111    span.red   = ChanToFixed(vert->color[0]);
 112    span.green = ChanToFixed(vert->color[1]);
 113    span.blue  = ChanToFixed(vert->color[2]);
 114    span.alpha = ChanToFixed(vert->color[3]);
 115    span.redStep = 0;
 116    span.greenStep = 0;
 117    span.blueStep = 0;
 118    span.alphaStep = 0;
 119
 120    /* need these for fragment programs */
 121    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 122    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 123    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 124
 125    {
 126       GLfloat s, r, dsdx;
 127
 128       /* texcoord / pointcoord interpolants */
 129       s = 0.0;
 130       dsdx = 1.0 / size;
 131       if (ctx->Point.SpriteOrigin == GL_LOWER_LEFT) {
 132          t0 = 0.0;
 133          dtdy = 1.0 / size;
 134       }
 135       else {
 136          /* GL_UPPER_LEFT */
 137          t0 = 1.0;
 138          dtdy = -1.0 / size;
 139       }
 140
 141       ATTRIB_LOOP_BEGIN
 142          if (attr >= FRAG_ATTRIB_TEX0 && attr < FRAG_ATTRIB_VAR0) {
 143             const GLuint u = attr - FRAG_ATTRIB_TEX0;
 144             /* a texcoord */
 145             if (ctx->Point.CoordReplace[u]) {
 146                tCoords[numTcoords++] = attr;
 147
 148                if (ctx->Point.SpriteRMode == GL_ZERO)
 149                   r = 0.0F;
 150                else if (ctx->Point.SpriteRMode == GL_S)
 151                   r = vert->attrib[attr][0];
 152                else /* GL_R */
 153                   r = vert->attrib[attr][2];
 154
 155                span.attrStart[attr][0] = s;
 156                span.attrStart[attr][1] = 0.0; /* overwritten below */
 157                span.attrStart[attr][2] = r;
 158                span.attrStart[attr][3] = 1.0;
 159
 160                span.attrStepX[attr][0] = dsdx;
 161                span.attrStepX[attr][1] = 0.0;
 162                span.attrStepX[attr][2] = 0.0;
 163                span.attrStepX[attr][3] = 0.0;
 164
 165                span.attrStepY[attr][0] = 0.0;
 166                span.attrStepY[attr][1] = dtdy;
 167                span.attrStepY[attr][2] = 0.0;
 168                span.attrStepY[attr][3] = 0.0;
 169
 170                continue;
 171             }
 172          }
 173          else if (attr == FRAG_ATTRIB_FOGC) {
 174             /* GLSL gl_PointCoord is stored in fog.zw */
 175             span.attrStart[FRAG_ATTRIB_FOGC][2] = 0.0;
 176             span.attrStart[FRAG_ATTRIB_FOGC][3] = 0.0; /* t0 set below */
 177             span.attrStepX[FRAG_ATTRIB_FOGC][2] = dsdx;
 178             span.attrStepX[FRAG_ATTRIB_FOGC][3] = 0.0;
 179             span.attrStepY[FRAG_ATTRIB_FOGC][2] = 0.0;
 180             span.attrStepY[FRAG_ATTRIB_FOGC][3] = dtdy;
 181             tCoords[numTcoords++] = FRAG_ATTRIB_FOGC;
 182             continue;
 183          }
 184          /* use vertex's texcoord/attrib */
 185          COPY_4V(span.attrStart[attr], vert->attrib[attr]);
 186          ASSIGN_4V(span.attrStepX[attr], 0, 0, 0, 0);
 187          ASSIGN_4V(span.attrStepY[attr], 0, 0, 0, 0);
 188       ATTRIB_LOOP_END;
 189    }
 190
 191    /* compute pos, bounds and render */
 192    {
 193       const GLfloat x = vert->attrib[FRAG_ATTRIB_WPOS][0];
 194       const GLfloat y = vert->attrib[FRAG_ATTRIB_WPOS][1];
 195       GLint iSize = (GLint) (size + 0.5F);
 196       GLint xmin, xmax, ymin, ymax, iy;
 197       GLint iRadius;
 198       GLfloat tcoord = t0;
 199
 200       iSize = MAX2(1, iSize);
 201       iRadius = iSize / 2;
 202
 203       if (iSize & 1) {
 204          /* odd size */
 205          xmin = (GLint) (x - iRadius);
 206          xmax = (GLint) (x + iRadius);
 207          ymin = (GLint) (y - iRadius);
 208          ymax = (GLint) (y + iRadius);
 209       }
 210       else {
 211          /* even size */
 212          /* 0.501 factor allows conformance to pass */
 213          xmin = (GLint) (x + 0.501) - iRadius;
 214          xmax = xmin + iSize - 1;
 215          ymin = (GLint) (y + 0.501) - iRadius;
 216          ymax = ymin + iSize - 1;
 217       }
 218
 219       /* render spans */
 220       for (iy = ymin; iy <= ymax; iy++) {
 221          GLuint i;
 222          /* setup texcoord T for this row */
 223          for (i = 0; i < numTcoords; i++) {
 224             if (tCoords[i] == FRAG_ATTRIB_FOGC)
 225                span.attrStart[FRAG_ATTRIB_FOGC][3] = tcoord;
 226             else
 227                span.attrStart[tCoords[i]][1] = tcoord;
 228          }
 229
 230          /* these might get changed by span clipping */
 231          span.x = xmin;
 232          span.y = iy;
 233          span.end = xmax - xmin + 1;
 234
 235          _swrast_write_rgba_span(ctx, &span);
 236
 237          tcoord += dtdy;
 238       }
 239    }
 240 }
 241
 242
 243 /**
 244  * Draw smooth/antialiased point.  RGB or CI mode.
 245  */
 246 static void
 247 smooth_point(GLcontext *ctx, const SWvertex *vert)
 248 {
 249    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 250    const GLboolean ciMode = !ctx->Visual.rgbMode;
 251    SWspan span;
 252    GLfloat size, alphaAtten;
 253
 254    CULL_INVALID(vert);
 255
 256    /* z coord */
 257    if (ctx->DrawBuffer->Visual.depthBits <= 16)
 258       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 259    else
 260       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 261    span.zStep = 0;
 262
 263    size = get_size(ctx, vert, GL_TRUE);
 264
 265    /* alpha attenuation / fade factor */
 266    if (ctx->Multisample._Enabled) {
 267       if (vert->pointSize >= ctx->Point.Threshold) {
 268          alphaAtten = 1.0F;
 269       }
 270       else {
 271          GLfloat dsize = vert->pointSize / ctx->Point.Threshold;
 272          alphaAtten = dsize * dsize;
 273       }
 274    }
 275    else {
 276       alphaAtten = 1.0;
 277    }
 278    (void) alphaAtten; /* not used */
 279
 280    /* span init */
 281    INIT_SPAN(span, GL_POINT);
 282    span.interpMask = SPAN_Z | SPAN_RGBA;
 283    span.arrayMask = SPAN_COVERAGE | SPAN_MASK;
 284
 285    span.facing = swrast->PointLineFacing;
 286
 287    span.red   = ChanToFixed(vert->color[0]);
 288    span.green = ChanToFixed(vert->color[1]);
 289    span.blue  = ChanToFixed(vert->color[2]);
 290    span.alpha = ChanToFixed(vert->color[3]);
 291    span.redStep = 0;
 292    span.greenStep = 0;
 293    span.blueStep = 0;
 294    span.alphaStep = 0;
 295
 296    /* need these for fragment programs */
 297    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 298    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 299    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 300
 301    ATTRIB_LOOP_BEGIN
 302       COPY_4V(span.attrStart[attr], vert->attrib[attr]);
 303       ASSIGN_4V(span.attrStepX[attr], 0, 0, 0, 0);
 304       ASSIGN_4V(span.attrStepY[attr], 0, 0, 0, 0);
 305    ATTRIB_LOOP_END
 306
 307    /* compute pos, bounds and render */
 308    {
 309       const GLfloat x = vert->attrib[FRAG_ATTRIB_WPOS][0];
 310       const GLfloat y = vert->attrib[FRAG_ATTRIB_WPOS][1];
 311       const GLfloat radius = 0.5F * size;
 312       const GLfloat rmin = radius - 0.7071F;  /* 0.7071 = sqrt(2)/2 */
 313       const GLfloat rmax = radius + 0.7071F;
 314       const GLfloat rmin2 = MAX2(0.0F, rmin * rmin);
 315       const GLfloat rmax2 = rmax * rmax;
 316       const GLfloat cscale = 1.0F / (rmax2 - rmin2);
 317       const GLint xmin = (GLint) (x - radius);
 318       const GLint xmax = (GLint) (x + radius);
 319       const GLint ymin = (GLint) (y - radius);
 320       const GLint ymax = (GLint) (y + radius);
 321       GLint ix, iy;
 322
 323       for (iy = ymin; iy <= ymax; iy++) {
 324
 325          /* these might get changed by span clipping */
 326          span.x = xmin;
 327          span.y = iy;
 328          span.end = xmax - xmin + 1;
 329
 330          /* compute coverage for each pixel in span */
 331          for (ix = xmin; ix <= xmax; ix++) {
 332             const GLfloat dx = ix - x + 0.5F;
 333             const GLfloat dy = iy - y + 0.5F;
 334             const GLfloat dist2 = dx * dx + dy * dy;
 335             GLfloat coverage;
 336
 337             if (dist2 < rmax2) {
 338                if (dist2 >= rmin2) {
 339                   /* compute partial coverage */
 340                   coverage = 1.0F - (dist2 - rmin2) * cscale;
 341                   if (ciMode) {
 342                      /* coverage in [0,15] */
 343                      coverage *= 15.0;
 344                   }
 345                }
 346                else {
 347                   /* full coverage */
 348                   coverage = 1.0F;
 349                }
 350                span.array->mask[ix - xmin] = 1;
 351             }
 352             else {
 353                /* zero coverage - fragment outside the radius */
 354                coverage = 0.0;
 355                span.array->mask[ix - xmin] = 0;
 356             }
 357             span.array->coverage[ix - xmin] = coverage;
 358          }
 359
 360          /* render span */
 361          _swrast_write_rgba_span(ctx, &span);
 362
 363       }
 364    }
 365 }
 366
 367
 368 /**
 369  * Draw large (size >= 1) non-AA point.  RGB or CI mode.
 370  */
 371 static void
 372 large_point(GLcontext *ctx, const SWvertex *vert)
 373 {
 374    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 375    const GLboolean ciMode = !ctx->Visual.rgbMode;
 376    SWspan span;
 377    GLfloat size;
 378
 379    CULL_INVALID(vert);
 380
 381    /* z coord */
 382    if (ctx->DrawBuffer->Visual.depthBits <= 16)
 383       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 384    else
 385       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 386    span.zStep = 0;
 387
 388    size = get_size(ctx, vert, GL_FALSE);
 389
 390    /* span init */
 391    INIT_SPAN(span, GL_POINT);
 392    span.arrayMask = SPAN_XY;
 393    span.facing = swrast->PointLineFacing;
 394
 395    if (ciMode) {
 396       span.interpMask = SPAN_Z | SPAN_INDEX;
 397       span.index = FloatToFixed(vert->attrib[FRAG_ATTRIB_CI][0]);
 398       span.indexStep = 0;
 399    }
 400    else {
 401       span.interpMask = SPAN_Z | SPAN_RGBA;
 402       span.red   = ChanToFixed(vert->color[0]);
 403       span.green = ChanToFixed(vert->color[1]);
 404       span.blue  = ChanToFixed(vert->color[2]);
 405       span.alpha = ChanToFixed(vert->color[3]);
 406       span.redStep = 0;
 407       span.greenStep = 0;
 408       span.blueStep = 0;
 409       span.alphaStep = 0;
 410    }
 411
 412    /* need these for fragment programs */
 413    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 414    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 415    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 416
 417    ATTRIB_LOOP_BEGIN
 418       COPY_4V(span.attrStart[attr], vert->attrib[attr]);
 419       ASSIGN_4V(span.attrStepX[attr], 0, 0, 0, 0);
 420       ASSIGN_4V(span.attrStepY[attr], 0, 0, 0, 0);
 421    ATTRIB_LOOP_END
 422
 423    /* compute pos, bounds and render */
 424    {
 425       const GLfloat x = vert->attrib[FRAG_ATTRIB_WPOS][0];
 426       const GLfloat y = vert->attrib[FRAG_ATTRIB_WPOS][1];
 427       GLint iSize = (GLint) (size + 0.5F);
 428       GLint xmin, xmax, ymin, ymax, ix, iy;
 429       GLint iRadius;
 430
 431       iSize = MAX2(1, iSize);
 432       iRadius = iSize / 2;
 433
 434       if (iSize & 1) {
 435          /* odd size */
 436          xmin = (GLint) (x - iRadius);
 437          xmax = (GLint) (x + iRadius);
 438          ymin = (GLint) (y - iRadius);
 439          ymax = (GLint) (y + iRadius);
 440       }
 441       else {
 442          /* even size */
 443          /* 0.501 factor allows conformance to pass */
 444          xmin = (GLint) (x + 0.501) - iRadius;
 445          xmax = xmin + iSize - 1;
 446          ymin = (GLint) (y + 0.501) - iRadius;
 447          ymax = ymin + iSize - 1;
 448       }
 449
 450       /* generate fragments */
 451       span.end = 0;
 452       for (iy = ymin; iy <= ymax; iy++) {
 453          for (ix = xmin; ix <= xmax; ix++) {
 454             span.array->x[span.end] = ix;
 455             span.array->y[span.end] = iy;
 456             span.end++;
 457          }
 458       }
 459       assert(span.end <= MAX_WIDTH);
 460       _swrast_write_rgba_span(ctx, &span);
 461    }
 462 }
 463
 464
 465 /**
 466  * Draw size=1, single-pixel point
 467  */
 468 static void
 469 pixel_point(GLcontext *ctx, const SWvertex *vert)
 470 {
 471    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 472    const GLboolean ciMode = !ctx->Visual.rgbMode;
 473    /*
 474     * Note that unlike the other functions, we put single-pixel points
 475     * into a special span array in order to render as many points as
 476     * possible with a single _swrast_write_rgba_span() call.
 477     */
 478    SWspan *span = &(swrast->PointSpan);
 479    GLuint count;
 480
 481    CULL_INVALID(vert);
 482
 483    /* Span init */
 484    span->interpMask = 0;
 485    span->arrayMask = SPAN_XY | SPAN_Z;
 486    if (ciMode)
 487       span->arrayMask |= SPAN_INDEX;
 488    else
 489       span->arrayMask |= SPAN_RGBA;
 490    /*span->arrayMask |= SPAN_LAMBDA;*/
 491    span->arrayAttribs = swrast->_ActiveAttribMask; /* we'll produce these vals */
 492
 493    /* need these for fragment programs */
 494    span->attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 495    span->attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 496    span->attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 497
 498    /* check if we need to flush */
 499    if (span->end >= MAX_WIDTH ||
 500        (swrast->_RasterMask & (BLEND_BIT | LOGIC_OP_BIT | MASKING_BIT)) ||
 501        span->facing != swrast->PointLineFacing) {
 502       if (span->end > 0) {
 503          if (ciMode)
 504             _swrast_write_index_span(ctx, span);
 505          else
 506             _swrast_write_rgba_span(ctx, span);
 507          span->end = 0;
 508       }
 509    }
 510
 511    count = span->end;
 512
 513    span->facing = swrast->PointLineFacing;
 514
 515    /* fragment attributes */
 516    if (ciMode) {
 517       span->array->index[count] = (GLuint) vert->attrib[FRAG_ATTRIB_CI][0];
 518    }
 519    else {
 520       span->array->rgba[count][RCOMP] = vert->color[0];
 521       span->array->rgba[count][GCOMP] = vert->color[1];
 522       span->array->rgba[count][BCOMP] = vert->color[2];
 523       span->array->rgba[count][ACOMP] = vert->color[3];
 524    }
 525    ATTRIB_LOOP_BEGIN
 526       COPY_4V(span->array->attribs[attr][count], vert->attrib[attr]);
 527    ATTRIB_LOOP_END
 528
 529    /* fragment position */
 530    span->array->x[count] = (GLint) vert->attrib[FRAG_ATTRIB_WPOS][0];
 531    span->array->y[count] = (GLint) vert->attrib[FRAG_ATTRIB_WPOS][1];
 532    span->array->z[count] = (GLint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 533
 534    span->end = count + 1;
 535    ASSERT(span->end <= MAX_WIDTH);
 536 }
 537
 538
 539 /**
 540  * Add specular color to primary color, draw point, restore original
 541  * primary color.
 542  */
 543 void
 544 _swrast_add_spec_terms_point(GLcontext *ctx, const SWvertex *v0)
 545 {
 546    SWvertex *ncv0 = (SWvertex *) v0; /* cast away const */
 547    GLfloat rSum, gSum, bSum;
 548    GLchan cSave[4];
 549
 550    /* save */
 551    COPY_CHAN4(cSave, ncv0->color);
 552    /* sum */
 553    rSum = CHAN_TO_FLOAT(ncv0->color[0]) + ncv0->attrib[FRAG_ATTRIB_COL1][0];
 554    gSum = CHAN_TO_FLOAT(ncv0->color[1]) + ncv0->attrib[FRAG_ATTRIB_COL1][1];
 555    bSum = CHAN_TO_FLOAT(ncv0->color[2]) + ncv0->attrib[FRAG_ATTRIB_COL1][2];
 556    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[0], rSum);
 557    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[1], gSum);
 558    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[2], bSum);
 559    /* draw */
 560    SWRAST_CONTEXT(ctx)->SpecPoint(ctx, ncv0);
 561    /* restore */
 562    COPY_CHAN4(ncv0->color, cSave);
 563 }
 564
 565
 566 /**
 567  * Examine current state to determine which point drawing function to use.
 568  */
 569 void
 570 _swrast_choose_point(GLcontext *ctx)
 571 {
 572    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 573
 574    if (ctx->RenderMode == GL_RENDER) {
 575       if (ctx->Point.PointSprite) {
 576          swrast->Point = sprite_point;
 577       }
 578       else if (ctx->Point.SmoothFlag) {
 579          swrast->Point = smooth_point;
 580       }
 581       else if (ctx->Point.Size > 1.0 ||
 582                ctx->Point._Attenuated ||
 583                ctx->VertexProgram.PointSizeEnabled) {
 584          swrast->Point = large_point;
 585       }
 586       else {
 587          swrast->Point = pixel_point;
 588       }
 589    }
 590    else if (ctx->RenderMode == GL_FEEDBACK) {
 591       swrast->Point = _swrast_feedback_point;
 592    }
 593    else {
 594       /* GL_SELECT mode */
 595       swrast->Point = _swrast_select_point;
 596    }
 597 }