src/mesa/swrast/s_accum.c

   1 /* $Id: s_accum.c,v 1.12 2001/07/13 20:07:37 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27
  28 #include "glheader.h"
  29 #include "context.h"
  30 #include "macros.h"
  31 #include "mmath.h"
  32 #include "mem.h"
  33
  34 #include "s_accum.h"
  35 #include "s_alphabuf.h"
  36 #include "s_context.h"
  37 #include "s_masking.h"
  38 #include "s_span.h"
  39
  40
  41 /*
  42  * Accumulation buffer notes
  43  *
  44  * Normally, accumulation buffer values are GLshorts with values in
  45  * [-32767, 32767] which represent floating point colors in [-1, 1],
  46  * as suggested by the OpenGL specification.
  47  *
  48  * We optimize for the common case used for full-scene antialiasing:
  49  *    // start with accum buffer cleared to zero
  50  *    glAccum(GL_LOAD, w);   // or GL_ACCUM the first image
  51  *    glAccum(GL_ACCUM, w);
  52  *    ...
  53  *    glAccum(GL_ACCUM, w);
  54  *    glAccum(GL_RETURN, 1.0);
  55  * That is, we start with an empty accumulation buffer and accumulate
  56  * n images, each with weight w = 1/n.
  57  * In this scenario, we can simply store unscaled integer values in
  58  * the accum buffer instead of scaled integers.  We'll also keep track
  59  * of the w value so when we do GL_RETURN we simply divide the accumulated
  60  * values by n (=1/w).
  61  * This lets us avoid _many_ int->float->int conversions.
  62  */
  63
  64
  65 #if CHAN_BITS == 8
  66 #define USE_OPTIMIZED_ACCUM   /* enable the optimization */
  67 #endif
  68
  69
  70
  71 void
  72 _mesa_alloc_accum_buffer( GLcontext *ctx )
  73 {
  74    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  75    GLint n;
  76
  77    if (ctx->DrawBuffer->Accum) {
  78       FREE( ctx->DrawBuffer->Accum );
  79       ctx->DrawBuffer->Accum = NULL;
  80    }
  81
  82    /* allocate accumulation buffer if not already present */
  83    n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4 * sizeof(GLaccum);
  84    ctx->DrawBuffer->Accum = (GLaccum *) MALLOC( n );
  85    if (!ctx->DrawBuffer->Accum) {
  86       /* unable to setup accumulation buffer */
  87       _mesa_error( ctx, GL_OUT_OF_MEMORY, "glAccum" );
  88    }
  89 #ifdef USE_OPTIMIZED_ACCUM
  90    swrast->_IntegerAccumMode = GL_TRUE;
  91 #else
  92    swrast->_IntegerAccumMode = GL_FALSE;
  93 #endif
  94    swrast->_IntegerAccumScaler = 0.0;
  95 }
  96
  97
  98
  99
 100
 101
 102 /*
 103  * This is called when we fall out of optimized/unscaled accum buffer mode.
 104  * That is, we convert each unscaled accum buffer value into a scaled value
 105  * representing the range[-1, 1].
 106  */
 107 static void rescale_accum( GLcontext *ctx )
 108 {
 109    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 110    const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4;
 111    const GLfloat s = swrast->_IntegerAccumScaler * (32767.0 / CHAN_MAXF);
 112    GLaccum *accum = ctx->DrawBuffer->Accum;
 113    GLuint i;
 114
 115    assert(swrast->_IntegerAccumMode);
 116    assert(accum);
 117
 118    for (i = 0; i < n; i++) {
 119       accum[i] = (GLaccum) (accum[i] * s);
 120    }
 121
 122    swrast->_IntegerAccumMode = GL_FALSE;
 123 }
 124
 125
 126
 127
 128
 129
 130 /*
 131  * Clear the accumulation Buffer.
 132  */
 133 void
 134 _mesa_clear_accum_buffer( GLcontext *ctx )
 135 {
 136    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 137    GLuint buffersize;
 138    GLfloat acc_scale;
 139
 140    if (ctx->Visual.accumRedBits==0) {
 141       /* No accumulation buffer! */
 142       return;
 143    }
 144
 145    if (sizeof(GLaccum)==1) {
 146       acc_scale = 127.0;
 147    }
 148    else if (sizeof(GLaccum)==2) {
 149       acc_scale = 32767.0;
 150    }
 151    else {
 152       acc_scale = 1.0F;
 153    }
 154
 155    /* number of pixels */
 156    buffersize = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
 157
 158    if (!ctx->DrawBuffer->Accum) {
 159       /* try to alloc accumulation buffer */
 160       ctx->DrawBuffer->Accum = (GLaccum *)
 161                            MALLOC( buffersize * 4 * sizeof(GLaccum) );
 162    }
 163
 164    if (ctx->DrawBuffer->Accum) {
 165       if (ctx->Scissor.Enabled) {
 166          /* Limit clear to scissor box */
 167          const GLaccum r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 168          const GLaccum g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 169          const GLaccum b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 170          const GLaccum a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 171          GLint i, j;
 172          GLint width, height;
 173          GLaccum *row;
 174          /* size of region to clear */
 175          width = 4 * (ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin);
 176          height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 177          /* ptr to first element to clear */
 178          row = ctx->DrawBuffer->Accum
 179                + 4 * (ctx->DrawBuffer->_Ymin * ctx->DrawBuffer->Width
 180                       + ctx->DrawBuffer->_Xmin);
 181          for (j=0;j<height;j++) {
 182             for (i=0;i<width;i+=4) {
 183                row[i+0] = r;
 184                row[i+1] = g;
 185                row[i+2] = b;
 186                row[i+3] = a;
 187             }
 188             row += 4 * ctx->DrawBuffer->Width;
 189          }
 190       }
 191       else {
 192          /* clear whole buffer */
 193          if (ctx->Accum.ClearColor[0]==0.0 &&
 194              ctx->Accum.ClearColor[1]==0.0 &&
 195              ctx->Accum.ClearColor[2]==0.0 &&
 196              ctx->Accum.ClearColor[3]==0.0) {
 197             /* Black */
 198             BZERO( ctx->DrawBuffer->Accum, buffersize * 4 * sizeof(GLaccum) );
 199          }
 200          else {
 201             /* Not black */
 202             const GLaccum r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 203             const GLaccum g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 204             const GLaccum b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 205             const GLaccum a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 206             GLaccum *acc = ctx->DrawBuffer->Accum;
 207             GLuint i;
 208             for (i=0;i<buffersize;i++) {
 209                *acc++ = r;
 210                *acc++ = g;
 211                *acc++ = b;
 212                *acc++ = a;
 213             }
 214          }
 215       }
 216
 217       /* update optimized accum state vars */
 218       if (ctx->Accum.ClearColor[0] == 0.0 && ctx->Accum.ClearColor[1] == 0.0 &&
 219           ctx->Accum.ClearColor[2] == 0.0 && ctx->Accum.ClearColor[3] == 0.0) {
 220 #ifdef USE_OPTIMIZED_ACCUM
 221          swrast->_IntegerAccumMode = GL_TRUE;
 222 #else
 223          swrast->_IntegerAccumMode = GL_FALSE;
 224 #endif
 225          swrast->_IntegerAccumScaler = 0.0;  /* denotes empty accum buffer */
 226       }
 227       else {
 228          swrast->_IntegerAccumMode = GL_FALSE;
 229       }
 230    }
 231 }
 232
 233
 234 void
 235 _swrast_Accum( GLcontext *ctx, GLenum op, GLfloat value,
 236                GLint xpos, GLint ypos,
 237                GLint width, GLint height )
 238
 239 {
 240    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 241    GLuint width4;
 242    GLfloat acc_scale;
 243    GLchan rgba[MAX_WIDTH][4];
 244    const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
 245
 246
 247    if (SWRAST_CONTEXT(ctx)->NewState)
 248       _swrast_validate_derived( ctx );
 249
 250    if (!ctx->DrawBuffer->Accum) {
 251       _mesa_warning(ctx,
 252                     "Calling glAccum() without an accumulation "
 253                     "buffer (low memory?)");
 254       return;
 255    }
 256
 257    if (sizeof(GLaccum)==1) {
 258       acc_scale = 127.0;
 259    }
 260    else if (sizeof(GLaccum)==2) {
 261       acc_scale = 32767.0;
 262    }
 263    else {
 264       acc_scale = 1.0F;
 265    }
 266
 267    width4 = 4 * width;
 268
 269    switch (op) {
 270       case GL_ADD:
 271          if (value != 0.0F) {
 272             const GLaccum val = (GLaccum) (value * acc_scale);
 273             GLint j;
 274             /* Leave optimized accum buffer mode */
 275             if (swrast->_IntegerAccumMode)
 276                rescale_accum(ctx);
 277             for (j = 0; j < height; j++) {
 278                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4*xpos;
 279                GLuint i;
 280                for (i = 0; i < width4; i++) {
 281                   acc[i] += val;
 282                }
 283                ypos++;
 284             }
 285          }
 286          break;
 287
 288       case GL_MULT:
 289          if (value != 1.0F) {
 290             GLint j;
 291             /* Leave optimized accum buffer mode */
 292             if (swrast->_IntegerAccumMode)
 293                rescale_accum(ctx);
 294             for (j = 0; j < height; j++) {
 295                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
 296                GLuint i;
 297                for (i = 0; i < width4; i++) {
 298                   acc[i] = (GLaccum) ( (GLfloat) acc[i] * value );
 299                }
 300                ypos++;
 301             }
 302          }
 303          break;
 304
 305       case GL_ACCUM:
 306          if (value == 0.0F)
 307             return;
 308
 309          (*swrast->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 310                                           ctx->Pixel.DriverReadBuffer );
 311
 312          /* May have to leave optimized accum buffer mode */
 313          if (swrast->_IntegerAccumScaler == 0.0 && value > 0.0 && value <= 1.0)
 314             swrast->_IntegerAccumScaler = value;
 315          if (swrast->_IntegerAccumMode && value != swrast->_IntegerAccumScaler)
 316             rescale_accum(ctx);
 317
 318          RENDER_START(swrast,ctx);
 319
 320          if (swrast->_IntegerAccumMode) {
 321             /* simply add integer color values into accum buffer */
 322             GLint j;
 323             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 324             assert(swrast->_IntegerAccumScaler > 0.0);
 325             assert(swrast->_IntegerAccumScaler <= 1.0);
 326             for (j = 0; j < height; j++) {
 327
 328                GLint i, i4;
 329                _mesa_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 330                for (i = i4 = 0; i < width; i++, i4+=4) {
 331                   acc[i4+0] += rgba[i][RCOMP];
 332                   acc[i4+1] += rgba[i][GCOMP];
 333                   acc[i4+2] += rgba[i][BCOMP];
 334                   acc[i4+3] += rgba[i][ACOMP];
 335                }
 336                acc += width4;
 337                ypos++;
 338             }
 339          }
 340          else {
 341             /* scaled integer (or float) accum buffer */
 342             const GLfloat rscale = value * acc_scale / CHAN_MAXF;
 343             const GLfloat gscale = value * acc_scale / CHAN_MAXF;
 344             const GLfloat bscale = value * acc_scale / CHAN_MAXF;
 345             const GLfloat ascale = value * acc_scale / CHAN_MAXF;
 346             GLint j;
 347             for (j=0;j<height;j++) {
 348                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 349                GLint i;
 350                _mesa_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 351                for (i=0;i<width;i++) {
 352                   acc[0] += (GLaccum) ( (GLfloat) rgba[i][RCOMP] * rscale );
 353                   acc[1] += (GLaccum) ( (GLfloat) rgba[i][GCOMP] * gscale );
 354                   acc[2] += (GLaccum) ( (GLfloat) rgba[i][BCOMP] * bscale );
 355                   acc[3] += (GLaccum) ( (GLfloat) rgba[i][ACOMP] * ascale );
 356                   acc += 4;
 357                }
 358                ypos++;
 359             }
 360          }
 361          /* restore read buffer = draw buffer (the default) */
 362          (*swrast->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 363                                           ctx->Color.DriverDrawBuffer );
 364          RENDER_FINISH(swrast,ctx);
 365          break;
 366
 367       case GL_LOAD:
 368          (*swrast->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 369                                           ctx->Pixel.DriverReadBuffer );
 370
 371          /* This is a change to go into optimized accum buffer mode */
 372          if (value > 0.0 && value <= 1.0) {
 373 #ifdef USE_OPTIMIZED_ACCUM
 374             swrast->_IntegerAccumMode = GL_TRUE;
 375 #else
 376             swrast->_IntegerAccumMode = GL_FALSE;
 377 #endif
 378             swrast->_IntegerAccumScaler = value;
 379          }
 380          else {
 381             swrast->_IntegerAccumMode = GL_FALSE;
 382             swrast->_IntegerAccumScaler = 0.0;
 383          }
 384
 385          RENDER_START(swrast,ctx);
 386          if (swrast->_IntegerAccumMode) {
 387             /* just copy values into accum buffer */
 388             GLint j;
 389             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 390             assert(swrast->_IntegerAccumScaler > 0.0);
 391             assert(swrast->_IntegerAccumScaler <= 1.0);
 392             for (j = 0; j < height; j++) {
 393                GLint i, i4;
 394                _mesa_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 395                for (i = i4 = 0; i < width; i++, i4 += 4) {
 396                   acc[i4+0] = rgba[i][RCOMP];
 397                   acc[i4+1] = rgba[i][GCOMP];
 398                   acc[i4+2] = rgba[i][BCOMP];
 399                   acc[i4+3] = rgba[i][ACOMP];
 400                }
 401                acc += width4;
 402                ypos++;
 403             }
 404          }
 405          else {
 406             /* scaled integer (or float) accum buffer */
 407             const GLfloat rscale = value * acc_scale / CHAN_MAXF;
 408             const GLfloat gscale = value * acc_scale / CHAN_MAXF;
 409             const GLfloat bscale = value * acc_scale / CHAN_MAXF;
 410             const GLfloat ascale = value * acc_scale / CHAN_MAXF;
 411 #if 0
 412             const GLfloat d = 3.0 / acc_scale;  /* XXX what's this? */
 413 #endif
 414             GLint i, j;
 415             for (j = 0; j < height; j++) {
 416                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 417                _mesa_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 418                for (i=0;i<width;i++) {
 419 #if 0
 420                   *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale + d);
 421                   *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale + d);
 422                   *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale + d);
 423                   *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale + d);
 424 #else
 425                   *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale);
 426                   *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale);
 427                   *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale);
 428                   *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale);
 429 #endif
 430                }
 431                ypos++;
 432             }
 433          }
 434
 435          /* restore read buffer = draw buffer (the default) */
 436          (*swrast->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 437                                        ctx->Color.DriverDrawBuffer );
 438          RENDER_FINISH(swrast,ctx);
 439          break;
 440
 441       case GL_RETURN:
 442          /* May have to leave optimized accum buffer mode */
 443          if (swrast->_IntegerAccumMode && value != 1.0)
 444             rescale_accum(ctx);
 445
 446          RENDER_START(swrast,ctx);
 447 #ifdef USE_OPTIMIZED_ACCUM
 448          if (swrast->_IntegerAccumMode && swrast->_IntegerAccumScaler > 0) {
 449             /* build lookup table to avoid many floating point multiplies */
 450             static GLchan multTable[32768];
 451             static GLfloat prevMult = 0.0;
 452             const GLfloat mult = swrast->_IntegerAccumScaler;
 453             const GLint max = MIN2((GLint) (256 / mult), 32767);
 454             GLint j;
 455             if (mult != prevMult) {
 456                for (j = 0; j < max; j++)
 457                   multTable[j] = IROUND((GLfloat) j * mult);
 458                prevMult = mult;
 459             }
 460
 461             assert(swrast->_IntegerAccumScaler > 0.0);
 462             assert(swrast->_IntegerAccumScaler <= 1.0);
 463             for (j = 0; j < height; j++) {
 464                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 465                GLint i, i4;
 466                for (i = i4 = 0; i < width; i++, i4 += 4) {
 467                   ASSERT(acc[i4+0] < max);
 468                   ASSERT(acc[i4+1] < max);
 469                   ASSERT(acc[i4+2] < max);
 470                   ASSERT(acc[i4+3] < max);
 471                   rgba[i][RCOMP] = multTable[acc[i4+0]];
 472                   rgba[i][GCOMP] = multTable[acc[i4+1]];
 473                   rgba[i][BCOMP] = multTable[acc[i4+2]];
 474                   rgba[i][ACOMP] = multTable[acc[i4+3]];
 475                }
 476                if (colorMask != 0xffffffff) {
 477                   _mesa_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 478                }
 479                (*swrast->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 480                                              (const GLchan (*)[4])rgba, NULL );
 481                if (ctx->DrawBuffer->UseSoftwareAlphaBuffers
 482                    && ctx->Color.ColorMask[ACOMP]) {
 483                   _mesa_write_alpha_span(ctx, width, xpos, ypos,
 484                                          (CONST GLchan (*)[4]) rgba, NULL);
 485                }
 486                ypos++;
 487             }
 488          }
 489          else
 490 #endif /* USE_OPTIMIZED_ACCUM */
 491          {
 492             /* scaled integer (or float) accum buffer */
 493             const GLfloat rscale = value / acc_scale * CHAN_MAXF;
 494             const GLfloat gscale = value / acc_scale * CHAN_MAXF;
 495             const GLfloat bscale = value / acc_scale * CHAN_MAXF;
 496             const GLfloat ascale = value / acc_scale * CHAN_MAXF;
 497             GLint i, j;
 498             for (j=0;j<height;j++) {
 499                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 500                for (i=0;i<width;i++) {
 501                   GLint r = IROUND( (GLfloat) (acc[0]) * rscale );
 502                   GLint g = IROUND( (GLfloat) (acc[1]) * gscale );
 503                   GLint b = IROUND( (GLfloat) (acc[2]) * bscale );
 504                   GLint a = IROUND( (GLfloat) (acc[3]) * ascale );
 505                   acc += 4;
 506                   rgba[i][RCOMP] = CLAMP( r, 0, CHAN_MAX );
 507                   rgba[i][GCOMP] = CLAMP( g, 0, CHAN_MAX );
 508                   rgba[i][BCOMP] = CLAMP( b, 0, CHAN_MAX );
 509                   rgba[i][ACOMP] = CLAMP( a, 0, CHAN_MAX );
 510                }
 511                if (colorMask != 0xffffffff) {
 512                   _mesa_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 513                }
 514                (*swrast->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 515                                              (const GLchan (*)[4])rgba, NULL );
 516                if (ctx->DrawBuffer->UseSoftwareAlphaBuffers
 517                    && ctx->Color.ColorMask[ACOMP]) {
 518                   _mesa_write_alpha_span(ctx, width, xpos, ypos,
 519                                          (CONST GLchan (*)[4]) rgba, NULL);
 520                }
 521                ypos++;
 522             }
 523          }
 524          RENDER_FINISH(swrast,ctx);
 525          break;
 526
 527       default:
 528          _mesa_error( ctx, GL_INVALID_ENUM, "glAccum" );
 529    }
 530 }