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 "s_context.h"
  31 #include "s_feedback.h"
  32 #include "s_points.h"
  33 #include "s_span.h"
  34
  35
  36 /**
  37  * Used to cull points with invalid coords
  38  */
  39 #define CULL_INVALID(V)                              \
  40    do {                                              \
  41       float tmp = (V)->attrib[FRAG_ATTRIB_WPOS][0]   \
  42                 + (V)->attrib[FRAG_ATTRIB_WPOS][1];  \
  43       if (IS_INF_OR_NAN(tmp))                        \
  44          return;                                     \
  45    } while(0)
  46
  47
  48
  49 /**
  50  * Get/compute the point size.
  51  * The size may come from a vertex shader, or computed with attentuation
  52  * or just the glPointSize value.
  53  * Must also clamp to user-defined range and implmentation limits.
  54  */
  55 static INLINE GLfloat
  56 get_size(const GLcontext *ctx, const SWvertex *vert, GLboolean smoothed)
  57 {
  58    GLfloat size;
  59
  60    if (ctx->Point._Attenuated || ctx->VertexProgram.PointSizeEnabled) {
  61       /* use vertex's point size */
  62       size = vert->pointSize;
  63    }
  64    else {
  65       /* use constant point size */
  66       size = ctx->Point.Size;
  67    }
  68    /* always clamp to user-specified limits */
  69    size = CLAMP(size, ctx->Point.MinSize, ctx->Point.MaxSize);
  70    /* clamp to implementation limits */
  71    if (smoothed)
  72       size = CLAMP(size, ctx->Const.MinPointSizeAA, ctx->Const.MaxPointSizeAA);
  73    else
  74       size = CLAMP(size, ctx->Const.MinPointSize, ctx->Const.MaxPointSize);
  75
  76    return size;
  77 }
  78
  79
  80 /**
  81  * Draw a point sprite
  82  */
  83 static void
  84 sprite_point(GLcontext *ctx, const SWvertex *vert)
  85 {
  86    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  87    SWspan span;
  88    GLfloat size;
  89    GLuint tCoords[MAX_TEXTURE_COORD_UNITS + 1];
  90    GLuint numTcoords = 0;
  91    GLfloat t0, dtdy;
  92
  93    CULL_INVALID(vert);
  94
  95    /* z coord */
  96    if (ctx->DrawBuffer->Visual.depthBits <= 16)
  97       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
  98    else
  99       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 100    span.zStep = 0;
 101
 102    size = get_size(ctx, vert, GL_FALSE);
 103
 104    /* span init */
 105    INIT_SPAN(span, GL_POINT);
 106    span.interpMask = SPAN_Z | SPAN_RGBA;
 107
 108    span.facing = swrast->PointLineFacing;
 109
 110    span.red   = ChanToFixed(vert->color[0]);
 111    span.green = ChanToFixed(vert->color[1]);
 112    span.blue  = ChanToFixed(vert->color[2]);
 113    span.alpha = ChanToFixed(vert->color[3]);
 114    span.redStep = 0;
 115    span.greenStep = 0;
 116    span.blueStep = 0;
 117    span.alphaStep = 0;
 118
 119    /* need these for fragment programs */
 120    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 121    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 122    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 123
 124    {
 125       GLfloat s, r, dsdx;
 126
 127       /* texcoord / pointcoord interpolants */
 128       s = 0.0F;
 129       dsdx = 1.0F / size;
 130       if (ctx->Point.SpriteOrigin == GL_LOWER_LEFT) {
 131          dtdy = 1.0F / size;
 132          t0 = 0.5F * dtdy;
 133       }
 134       else {
 135          /* GL_UPPER_LEFT */
 136          dtdy = -1.0F / size;
 137          t0 = 1.0F + 0.5F * dtdy;
 138       }
 139
 140       ATTRIB_LOOP_BEGIN
 141          if (attr >= FRAG_ATTRIB_TEX0 && attr <= FRAG_ATTRIB_TEX7) {
 142             /* a texcoord attribute */
 143             const GLuint u = attr - FRAG_ATTRIB_TEX0;
 144             ASSERT(u < Elements(ctx->Point.CoordReplace));
 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_PNTC) {
 174             /* GLSL gl_PointCoord.xy (.zw undefined) */
 175             span.attrStart[FRAG_ATTRIB_PNTC][0] = 0.0;
 176             span.attrStart[FRAG_ATTRIB_PNTC][1] = 0.0; /* t0 set below */
 177             span.attrStepX[FRAG_ATTRIB_PNTC][0] = dsdx;
 178             span.attrStepX[FRAG_ATTRIB_PNTC][1] = 0.0;
 179             span.attrStepY[FRAG_ATTRIB_PNTC][0] = 0.0;
 180             span.attrStepY[FRAG_ATTRIB_PNTC][1] = dtdy;
 181             tCoords[numTcoords++] = FRAG_ATTRIB_PNTC;
 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             span.attrStart[tCoords[i]][1] = tcoord;
 225          }
 226
 227          /* these might get changed by span clipping */
 228          span.x = xmin;
 229          span.y = iy;
 230          span.end = xmax - xmin + 1;
 231
 232          _swrast_write_rgba_span(ctx, &span);
 233
 234          tcoord += dtdy;
 235       }
 236    }
 237 }
 238
 239
 240 /**
 241  * Draw smooth/antialiased point.  RGB or CI mode.
 242  */
 243 static void
 244 smooth_point(GLcontext *ctx, const SWvertex *vert)
 245 {
 246    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 247    SWspan span;
 248    GLfloat size, alphaAtten;
 249
 250    CULL_INVALID(vert);
 251
 252    /* z coord */
 253    if (ctx->DrawBuffer->Visual.depthBits <= 16)
 254       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 255    else
 256       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 257    span.zStep = 0;
 258
 259    size = get_size(ctx, vert, GL_TRUE);
 260
 261    /* alpha attenuation / fade factor */
 262    if (ctx->Multisample._Enabled) {
 263       if (vert->pointSize >= ctx->Point.Threshold) {
 264          alphaAtten = 1.0F;
 265       }
 266       else {
 267          GLfloat dsize = vert->pointSize / ctx->Point.Threshold;
 268          alphaAtten = dsize * dsize;
 269       }
 270    }
 271    else {
 272       alphaAtten = 1.0;
 273    }
 274    (void) alphaAtten; /* not used */
 275
 276    /* span init */
 277    INIT_SPAN(span, GL_POINT);
 278    span.interpMask = SPAN_Z | SPAN_RGBA;
 279    span.arrayMask = SPAN_COVERAGE | SPAN_MASK;
 280
 281    span.facing = swrast->PointLineFacing;
 282
 283    span.red   = ChanToFixed(vert->color[0]);
 284    span.green = ChanToFixed(vert->color[1]);
 285    span.blue  = ChanToFixed(vert->color[2]);
 286    span.alpha = ChanToFixed(vert->color[3]);
 287    span.redStep = 0;
 288    span.greenStep = 0;
 289    span.blueStep = 0;
 290    span.alphaStep = 0;
 291
 292    /* need these for fragment programs */
 293    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 294    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 295    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 296
 297    ATTRIB_LOOP_BEGIN
 298       COPY_4V(span.attrStart[attr], vert->attrib[attr]);
 299       ASSIGN_4V(span.attrStepX[attr], 0, 0, 0, 0);
 300       ASSIGN_4V(span.attrStepY[attr], 0, 0, 0, 0);
 301    ATTRIB_LOOP_END
 302
 303    /* compute pos, bounds and render */
 304    {
 305       const GLfloat x = vert->attrib[FRAG_ATTRIB_WPOS][0];
 306       const GLfloat y = vert->attrib[FRAG_ATTRIB_WPOS][1];
 307       const GLfloat radius = 0.5F * size;
 308       const GLfloat rmin = radius - 0.7071F;  /* 0.7071 = sqrt(2)/2 */
 309       const GLfloat rmax = radius + 0.7071F;
 310       const GLfloat rmin2 = MAX2(0.0F, rmin * rmin);
 311       const GLfloat rmax2 = rmax * rmax;
 312       const GLfloat cscale = 1.0F / (rmax2 - rmin2);
 313       const GLint xmin = (GLint) (x - radius);
 314       const GLint xmax = (GLint) (x + radius);
 315       const GLint ymin = (GLint) (y - radius);
 316       const GLint ymax = (GLint) (y + radius);
 317       GLint ix, iy;
 318
 319       for (iy = ymin; iy <= ymax; iy++) {
 320
 321          /* these might get changed by span clipping */
 322          span.x = xmin;
 323          span.y = iy;
 324          span.end = xmax - xmin + 1;
 325
 326          /* compute coverage for each pixel in span */
 327          for (ix = xmin; ix <= xmax; ix++) {
 328             const GLfloat dx = ix - x + 0.5F;
 329             const GLfloat dy = iy - y + 0.5F;
 330             const GLfloat dist2 = dx * dx + dy * dy;
 331             GLfloat coverage;
 332
 333             if (dist2 < rmax2) {
 334                if (dist2 >= rmin2) {
 335                   /* compute partial coverage */
 336                   coverage = 1.0F - (dist2 - rmin2) * cscale;
 337                }
 338                else {
 339                   /* full coverage */
 340                   coverage = 1.0F;
 341                }
 342                span.array->mask[ix - xmin] = 1;
 343             }
 344             else {
 345                /* zero coverage - fragment outside the radius */
 346                coverage = 0.0;
 347                span.array->mask[ix - xmin] = 0;
 348             }
 349             span.array->coverage[ix - xmin] = coverage;
 350          }
 351
 352          /* render span */
 353          _swrast_write_rgba_span(ctx, &span);
 354
 355       }
 356    }
 357 }
 358
 359
 360 /**
 361  * Draw large (size >= 1) non-AA point.  RGB or CI mode.
 362  */
 363 static void
 364 large_point(GLcontext *ctx, const SWvertex *vert)
 365 {
 366    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 367    SWspan span;
 368    GLfloat size;
 369
 370    CULL_INVALID(vert);
 371
 372    /* z coord */
 373    if (ctx->DrawBuffer->Visual.depthBits <= 16)
 374       span.z = FloatToFixed(vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 375    else
 376       span.z = (GLuint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 377    span.zStep = 0;
 378
 379    size = get_size(ctx, vert, GL_FALSE);
 380
 381    /* span init */
 382    INIT_SPAN(span, GL_POINT);
 383    span.arrayMask = SPAN_XY;
 384    span.facing = swrast->PointLineFacing;
 385
 386    span.interpMask = SPAN_Z | SPAN_RGBA;
 387    span.red   = ChanToFixed(vert->color[0]);
 388    span.green = ChanToFixed(vert->color[1]);
 389    span.blue  = ChanToFixed(vert->color[2]);
 390    span.alpha = ChanToFixed(vert->color[3]);
 391    span.redStep = 0;
 392    span.greenStep = 0;
 393    span.blueStep = 0;
 394    span.alphaStep = 0;
 395
 396    /* need these for fragment programs */
 397    span.attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 398    span.attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 399    span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 400
 401    ATTRIB_LOOP_BEGIN
 402       COPY_4V(span.attrStart[attr], vert->attrib[attr]);
 403       ASSIGN_4V(span.attrStepX[attr], 0, 0, 0, 0);
 404       ASSIGN_4V(span.attrStepY[attr], 0, 0, 0, 0);
 405    ATTRIB_LOOP_END
 406
 407    /* compute pos, bounds and render */
 408    {
 409       const GLfloat x = vert->attrib[FRAG_ATTRIB_WPOS][0];
 410       const GLfloat y = vert->attrib[FRAG_ATTRIB_WPOS][1];
 411       GLint iSize = (GLint) (size + 0.5F);
 412       GLint xmin, xmax, ymin, ymax, ix, iy;
 413       GLint iRadius;
 414
 415       iSize = MAX2(1, iSize);
 416       iRadius = iSize / 2;
 417
 418       if (iSize & 1) {
 419          /* odd size */
 420          xmin = (GLint) (x - iRadius);
 421          xmax = (GLint) (x + iRadius);
 422          ymin = (GLint) (y - iRadius);
 423          ymax = (GLint) (y + iRadius);
 424       }
 425       else {
 426          /* even size */
 427          /* 0.501 factor allows conformance to pass */
 428          xmin = (GLint) (x + 0.501) - iRadius;
 429          xmax = xmin + iSize - 1;
 430          ymin = (GLint) (y + 0.501) - iRadius;
 431          ymax = ymin + iSize - 1;
 432       }
 433
 434       /* generate fragments */
 435       span.end = 0;
 436       for (iy = ymin; iy <= ymax; iy++) {
 437          for (ix = xmin; ix <= xmax; ix++) {
 438             span.array->x[span.end] = ix;
 439             span.array->y[span.end] = iy;
 440             span.end++;
 441          }
 442       }
 443       assert(span.end <= MAX_WIDTH);
 444       _swrast_write_rgba_span(ctx, &span);
 445    }
 446 }
 447
 448
 449 /**
 450  * Draw size=1, single-pixel point
 451  */
 452 static void
 453 pixel_point(GLcontext *ctx, const SWvertex *vert)
 454 {
 455    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 456    /*
 457     * Note that unlike the other functions, we put single-pixel points
 458     * into a special span array in order to render as many points as
 459     * possible with a single _swrast_write_rgba_span() call.
 460     */
 461    SWspan *span = &(swrast->PointSpan);
 462    GLuint count;
 463
 464    CULL_INVALID(vert);
 465
 466    /* Span init */
 467    span->interpMask = 0;
 468    span->arrayMask = SPAN_XY | SPAN_Z;
 469    span->arrayMask |= SPAN_RGBA;
 470    /*span->arrayMask |= SPAN_LAMBDA;*/
 471    span->arrayAttribs = swrast->_ActiveAttribMask; /* we'll produce these vals */
 472
 473    /* need these for fragment programs */
 474    span->attrStart[FRAG_ATTRIB_WPOS][3] = 1.0F;
 475    span->attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0F;
 476    span->attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0F;
 477
 478    /* check if we need to flush */
 479    if (span->end >= MAX_WIDTH ||
 480        (swrast->_RasterMask & (BLEND_BIT | LOGIC_OP_BIT | MASKING_BIT)) ||
 481        span->facing != swrast->PointLineFacing) {
 482       if (span->end > 0) {
 483          _swrast_write_rgba_span(ctx, span);
 484          span->end = 0;
 485       }
 486    }
 487
 488    count = span->end;
 489
 490    span->facing = swrast->PointLineFacing;
 491
 492    /* fragment attributes */
 493    span->array->rgba[count][RCOMP] = vert->color[0];
 494    span->array->rgba[count][GCOMP] = vert->color[1];
 495    span->array->rgba[count][BCOMP] = vert->color[2];
 496    span->array->rgba[count][ACOMP] = vert->color[3];
 497
 498    ATTRIB_LOOP_BEGIN
 499       COPY_4V(span->array->attribs[attr][count], vert->attrib[attr]);
 500    ATTRIB_LOOP_END
 501
 502    /* fragment position */
 503    span->array->x[count] = (GLint) vert->attrib[FRAG_ATTRIB_WPOS][0];
 504    span->array->y[count] = (GLint) vert->attrib[FRAG_ATTRIB_WPOS][1];
 505    span->array->z[count] = (GLint) (vert->attrib[FRAG_ATTRIB_WPOS][2] + 0.5F);
 506
 507    span->end = count + 1;
 508    ASSERT(span->end <= MAX_WIDTH);
 509 }
 510
 511
 512 /**
 513  * Add specular color to primary color, draw point, restore original
 514  * primary color.
 515  */
 516 void
 517 _swrast_add_spec_terms_point(GLcontext *ctx, const SWvertex *v0)
 518 {
 519    SWvertex *ncv0 = (SWvertex *) v0; /* cast away const */
 520    GLfloat rSum, gSum, bSum;
 521    GLchan cSave[4];
 522
 523    /* save */
 524    COPY_CHAN4(cSave, ncv0->color);
 525    /* sum */
 526    rSum = CHAN_TO_FLOAT(ncv0->color[0]) + ncv0->attrib[FRAG_ATTRIB_COL1][0];
 527    gSum = CHAN_TO_FLOAT(ncv0->color[1]) + ncv0->attrib[FRAG_ATTRIB_COL1][1];
 528    bSum = CHAN_TO_FLOAT(ncv0->color[2]) + ncv0->attrib[FRAG_ATTRIB_COL1][2];
 529    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[0], rSum);
 530    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[1], gSum);
 531    UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[2], bSum);
 532    /* draw */
 533    SWRAST_CONTEXT(ctx)->SpecPoint(ctx, ncv0);
 534    /* restore */
 535    COPY_CHAN4(ncv0->color, cSave);
 536 }
 537
 538
 539 /**
 540  * Examine current state to determine which point drawing function to use.
 541  */
 542 void
 543 _swrast_choose_point(GLcontext *ctx)
 544 {
 545    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 546    const GLfloat size = CLAMP(ctx->Point.Size,
 547                               ctx->Point.MinSize,
 548                               ctx->Point.MaxSize);
 549
 550    if (ctx->RenderMode == GL_RENDER) {
 551       if (ctx->Point.PointSprite) {
 552          swrast->Point = sprite_point;
 553       }
 554       else if (ctx->Point.SmoothFlag) {
 555          swrast->Point = smooth_point;
 556       }
 557       else if (size > 1.0 ||
 558                ctx->Point._Attenuated ||
 559                ctx->VertexProgram.PointSizeEnabled) {
 560          swrast->Point = large_point;
 561       }
 562       else {
 563          swrast->Point = pixel_point;
 564       }
 565    }
 566    else if (ctx->RenderMode == GL_FEEDBACK) {
 567       swrast->Point = _swrast_feedback_point;
 568    }
 569    else {
 570       /* GL_SELECT mode */
 571       swrast->Point = _swrast_select_point;
 572    }
 573 }