src/mesa/main/accum.c

   1 /* $Id: accum.c,v 1.13 1999/11/25 17:36:48 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.3
   6  *
   7  * Copyright (C) 1999  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 #ifdef PC_HEADER
  29 #include "all.h"
  30 #else
  31 #include "glheader.h"
  32 #include "accum.h"
  33 #include "context.h"
  34 #include "mem.h"
  35 #include "masking.h"
  36 #include "span.h"
  37 #include "types.h"
  38 #endif
  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 #define USE_OPTIMIZED_ACCUM   /* enable the optimization */
  66
  67
  68
  69 void gl_alloc_accum_buffer( GLcontext *ctx )
  70 {
  71    GLint n;
  72
  73    if (ctx->DrawBuffer->Accum) {
  74       FREE( ctx->DrawBuffer->Accum );
  75       ctx->DrawBuffer->Accum = NULL;
  76    }
  77
  78    /* allocate accumulation buffer if not already present */
  79    n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4 * sizeof(GLaccum);
  80    ctx->DrawBuffer->Accum = (GLaccum *) MALLOC( n );
  81    if (!ctx->DrawBuffer->Accum) {
  82       /* unable to setup accumulation buffer */
  83       gl_error( ctx, GL_OUT_OF_MEMORY, "glAccum" );
  84    }
  85 #ifdef USE_OPTIMIZED_ACCUM
  86    ctx->IntegerAccumMode = GL_TRUE;
  87 #else
  88    ctx->IntegerAccumMode = GL_FALSE;
  89 #endif
  90    ctx->IntegerAccumScaler = 0.0;
  91 }
  92
  93
  94
  95 void
  96 _mesa_ClearAccum( GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha )
  97 {
  98    GET_CURRENT_CONTEXT(ctx);
  99    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glAccum");
 100
 101    ctx->Accum.ClearColor[0] = CLAMP( red, -1.0, 1.0 );
 102    ctx->Accum.ClearColor[1] = CLAMP( green, -1.0, 1.0 );
 103    ctx->Accum.ClearColor[2] = CLAMP( blue, -1.0, 1.0 );
 104    ctx->Accum.ClearColor[3] = CLAMP( alpha, -1.0, 1.0 );
 105 }
 106
 107
 108
 109 /*
 110  * This is called when we fall out of optimized/unscaled accum buffer mode.
 111  * That is, we convert each unscaled accum buffer value into a scaled value
 112  * representing the range[-1, 1].
 113  */
 114 static void rescale_accum( GLcontext *ctx )
 115 {
 116    const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4;
 117    const GLfloat fChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 118    const GLfloat s = ctx->IntegerAccumScaler * (32767.0 / fChanMax);
 119    GLaccum *accum = ctx->DrawBuffer->Accum;
 120    GLuint i;
 121
 122    assert(ctx->IntegerAccumMode);
 123    assert(accum);
 124
 125    for (i = 0; i < n; i++) {
 126       accum[i] = (GLaccum) (accum[i] * s);
 127    }
 128
 129    ctx->IntegerAccumMode = GL_FALSE;
 130 }
 131
 132
 133
 134 void
 135 _mesa_Accum( GLenum op, GLfloat value )
 136 {
 137    GET_CURRENT_CONTEXT(ctx);
 138    GLuint xpos, ypos, width, height, width4;
 139    GLfloat acc_scale;
 140    GLubyte rgba[MAX_WIDTH][4];
 141    const GLint iChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 142    const GLfloat fChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 143
 144    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glAccum");
 145
 146    if (ctx->Visual->AccumBits == 0 || ctx->DrawBuffer != ctx->ReadBuffer) {
 147       gl_error(ctx, GL_INVALID_OPERATION, "glAccum");
 148       return;
 149    }
 150
 151    if (!ctx->DrawBuffer->Accum) {
 152       gl_warning(ctx, "Calling glAccum() without an accumulation buffer (low memory?)");
 153       return;
 154    }
 155
 156    if (sizeof(GLaccum)==1) {
 157       acc_scale = 127.0;
 158    }
 159    else if (sizeof(GLaccum)==2) {
 160       acc_scale = 32767.0;
 161    }
 162    else {
 163       /* sizeof(GLaccum) > 2 (Cray) */
 164       acc_scale = (float) SHRT_MAX;
 165    }
 166
 167    if (ctx->NewState)
 168       gl_update_state( ctx );
 169
 170    /* Determine region to operate upon. */
 171    if (ctx->Scissor.Enabled) {
 172       xpos = ctx->Scissor.X;
 173       ypos = ctx->Scissor.Y;
 174       width = ctx->Scissor.Width;
 175       height = ctx->Scissor.Height;
 176    }
 177    else {
 178       /* whole window */
 179       xpos = 0;
 180       ypos = 0;
 181       width = ctx->DrawBuffer->Width;
 182       height = ctx->DrawBuffer->Height;
 183    }
 184
 185    width4 = 4 * width;
 186
 187    switch (op) {
 188       case GL_ADD:
 189          {
 190             const GLaccum intVal = (GLaccum) (value * acc_scale);
 191             GLuint j;
 192             /* Leave optimized accum buffer mode */
 193             if (ctx->IntegerAccumMode)
 194                rescale_accum(ctx);
 195             for (j = 0; j < height; j++) {
 196                GLaccum * acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
 197                GLuint i;
 198                for (i = 0; i < width4; i++) {
 199                   acc[i] += intVal;
 200                }
 201                ypos++;
 202             }
 203          }
 204          break;
 205
 206       case GL_MULT:
 207          {
 208             GLuint j;
 209             /* Leave optimized accum buffer mode */
 210             if (ctx->IntegerAccumMode)
 211                rescale_accum(ctx);
 212             for (j = 0; j < height; j++) {
 213                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
 214                GLuint i;
 215                for (i = 0; i < width4; i++) {
 216                   acc[i] = (GLaccum) ( (GLfloat) acc[i] * value );
 217                }
 218                ypos++;
 219             }
 220          }
 221          break;
 222
 223       case GL_ACCUM:
 224          (*ctx->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 225                                        ctx->Pixel.DriverReadBuffer );
 226
 227          /* May have to leave optimized accum buffer mode */
 228          if (ctx->IntegerAccumScaler == 0.0 && value > 0.0 && value <= 1.0)
 229             ctx->IntegerAccumScaler = value;
 230          if (ctx->IntegerAccumMode && value != ctx->IntegerAccumScaler)
 231             rescale_accum(ctx);
 232
 233          if (ctx->IntegerAccumMode) {
 234             /* simply add integer color values into accum buffer */
 235             GLuint j;
 236             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 237             assert(ctx->IntegerAccumScaler > 0.0);
 238             assert(ctx->IntegerAccumScaler <= 1.0);
 239             for (j = 0; j < height; j++) {
 240
 241                GLuint i, i4;
 242                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 243                for (i = i4 = 0; i < width; i++, i4+=4) {
 244                   acc[i4+0] += rgba[i][RCOMP];
 245                   acc[i4+1] += rgba[i][GCOMP];
 246                   acc[i4+2] += rgba[i][BCOMP];
 247                   acc[i4+3] += rgba[i][ACOMP];
 248                }
 249                acc += width4;
 250                ypos++;
 251             }
 252          }
 253          else {
 254             /* scaled integer accum buffer */
 255             const GLfloat rscale = value * acc_scale / fChanMax;
 256             const GLfloat gscale = value * acc_scale / fChanMax;
 257             const GLfloat bscale = value * acc_scale / fChanMax;
 258             const GLfloat ascale = value * acc_scale / fChanMax;
 259             GLuint j;
 260             for (j=0;j<height;j++) {
 261                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 262                GLuint i;
 263                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 264                for (i=0;i<width;i++) {
 265                   *acc += (GLaccum) ( (GLfloat) rgba[i][RCOMP] * rscale );  acc++;
 266                   *acc += (GLaccum) ( (GLfloat) rgba[i][GCOMP] * gscale );  acc++;
 267                   *acc += (GLaccum) ( (GLfloat) rgba[i][BCOMP] * bscale );  acc++;
 268                   *acc += (GLaccum) ( (GLfloat) rgba[i][ACOMP] * ascale );  acc++;
 269                }
 270                ypos++;
 271             }
 272          }
 273          /* restore read buffer = draw buffer (the default) */
 274          (*ctx->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 275                                        ctx->Color.DriverDrawBuffer );
 276          break;
 277
 278       case GL_LOAD:
 279          (*ctx->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 280                                        ctx->Pixel.DriverReadBuffer );
 281
 282          /* This is a change to go into optimized accum buffer mode */
 283          if (value > 0.0 && value <= 1.0) {
 284 #ifdef USE_OPTIMIZED_ACCUM
 285             ctx->IntegerAccumMode = GL_TRUE;
 286 #else
 287             ctx->IntegerAccumMode = GL_FALSE;
 288 #endif
 289             ctx->IntegerAccumScaler = value;
 290          }
 291          else {
 292             ctx->IntegerAccumMode = GL_FALSE;
 293             ctx->IntegerAccumScaler = 0.0;
 294          }
 295
 296          if (ctx->IntegerAccumMode) {
 297             /* just copy values into accum buffer */
 298             GLuint j;
 299             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 300             assert(ctx->IntegerAccumScaler > 0.0);
 301             assert(ctx->IntegerAccumScaler <= 1.0);
 302             for (j = 0; j < height; j++) {
 303                GLuint i, i4;
 304                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 305                for (i = i4 = 0; i < width; i++, i4 += 4) {
 306                   acc[i4+0] = rgba[i][RCOMP];
 307                   acc[i4+1] = rgba[i][GCOMP];
 308                   acc[i4+2] = rgba[i][BCOMP];
 309                   acc[i4+3] = rgba[i][ACOMP];
 310                }
 311                acc += width4;
 312                ypos++;
 313             }
 314          }
 315          else {
 316             /* scaled integer accum buffer */
 317             const GLfloat rscale = value * acc_scale / fChanMax;
 318             const GLfloat gscale = value * acc_scale / fChanMax;
 319             const GLfloat bscale = value * acc_scale / fChanMax;
 320             const GLfloat ascale = value * acc_scale / fChanMax;
 321             const GLfloat d = 3.0 / acc_scale;
 322             GLuint i, j;
 323             for (j = 0; j < height; j++) {
 324                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 325                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 326                for (i=0;i<width;i++) {
 327                   *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale + d);
 328                   *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale + d);
 329                   *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale + d);
 330                   *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale + d);
 331                }
 332                ypos++;
 333             }
 334          }
 335
 336          /* restore read buffer = draw buffer (the default) */
 337          (*ctx->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 338                                        ctx->Color.DriverDrawBuffer );
 339          break;
 340
 341       case GL_RETURN:
 342          /* May have to leave optimized accum buffer mode */
 343          if (ctx->IntegerAccumMode && value != 1.0)
 344             rescale_accum(ctx);
 345
 346          if (ctx->IntegerAccumMode) {
 347             /* build lookup table to avoid many floating point multiplies */
 348             const GLfloat mult = ctx->IntegerAccumScaler;
 349             static GLchan multTable[32768];
 350             static GLfloat prevMult = 0.0;
 351             GLuint j;
 352             const GLint max = 256 / mult;
 353             if (mult != prevMult) {
 354                assert(max <= 32768);
 355                for (j = 0; j < max; j++)
 356                   multTable[j] = (GLint) ((GLfloat) j * mult + 0.5F);
 357                prevMult = mult;
 358             }
 359
 360             assert(ctx->IntegerAccumScaler > 0.0);
 361             assert(ctx->IntegerAccumScaler <= 1.0);
 362             for (j = 0; j < height; j++) {
 363                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 364                GLuint i, i4;
 365                for (i = i4 = 0; i < width; i++, i4 += 4) {
 366                   ASSERT(acc[i4+0] < max);
 367                   ASSERT(acc[i4+1] < max);
 368                   ASSERT(acc[i4+2] < max);
 369                   ASSERT(acc[i4+3] < max);
 370                   rgba[i][RCOMP] = multTable[acc[i4+0]];
 371                   rgba[i][GCOMP] = multTable[acc[i4+1]];
 372                   rgba[i][BCOMP] = multTable[acc[i4+2]];
 373                   rgba[i][ACOMP] = multTable[acc[i4+3]];
 374                }
 375                if (ctx->Color.SWmasking) {
 376                   gl_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 377                }
 378                (*ctx->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 379                                              (const GLubyte (*)[4])rgba, NULL );
 380                ypos++;
 381             }
 382          }
 383          else {
 384             const GLfloat rscale = value / acc_scale * fChanMax;
 385             const GLfloat gscale = value / acc_scale * fChanMax;
 386             const GLfloat bscale = value / acc_scale * fChanMax;
 387             const GLfloat ascale = value / acc_scale * fChanMax;
 388             GLuint i, j;
 389             for (j=0;j<height;j++) {
 390                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 391                for (i=0;i<width;i++) {
 392                   GLint r, g, b, a;
 393                   r = (GLint) ( (GLfloat) (*acc++) * rscale + 0.5F );
 394                   g = (GLint) ( (GLfloat) (*acc++) * gscale + 0.5F );
 395                   b = (GLint) ( (GLfloat) (*acc++) * bscale + 0.5F );
 396                   a = (GLint) ( (GLfloat) (*acc++) * ascale + 0.5F );
 397                   rgba[i][RCOMP] = CLAMP( r, 0, iChanMax );
 398                   rgba[i][GCOMP] = CLAMP( g, 0, iChanMax );
 399                   rgba[i][BCOMP] = CLAMP( b, 0, iChanMax );
 400                   rgba[i][ACOMP] = CLAMP( a, 0, iChanMax );
 401                }
 402                if (ctx->Color.SWmasking) {
 403                   gl_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 404                }
 405                (*ctx->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 406                                              (const GLubyte (*)[4])rgba, NULL );
 407                ypos++;
 408             }
 409          }
 410          break;
 411
 412       default:
 413          gl_error( ctx, GL_INVALID_ENUM, "glAccum" );
 414    }
 415 }
 416
 417
 418
 419 /*
 420  * Clear the accumulation Buffer.
 421  */
 422 void gl_clear_accum_buffer( GLcontext *ctx )
 423 {
 424    GLuint buffersize;
 425    GLfloat acc_scale;
 426
 427    if (ctx->Visual->AccumBits==0) {
 428       /* No accumulation buffer! */
 429       return;
 430    }
 431
 432    if (sizeof(GLaccum)==1) {
 433       acc_scale = 127.0;
 434    }
 435    else if (sizeof(GLaccum)==2) {
 436       acc_scale = 32767.0;
 437    }
 438    else {
 439       /* sizeof(GLaccum) > 2 (Cray) */
 440       acc_scale = (float) SHRT_MAX;
 441    }
 442
 443    /* number of pixels */
 444    buffersize = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
 445
 446    if (!ctx->DrawBuffer->Accum) {
 447       /* try to alloc accumulation buffer */
 448       ctx->DrawBuffer->Accum = (GLaccum *)
 449                            MALLOC( buffersize * 4 * sizeof(GLaccum) );
 450    }
 451
 452    if (ctx->DrawBuffer->Accum) {
 453       if (ctx->Scissor.Enabled) {
 454          /* Limit clear to scissor box */
 455          GLaccum r, g, b, a;
 456          GLint i, j;
 457          GLint width, height;
 458          GLaccum *row;
 459          r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 460          g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 461          b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 462          a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 463          /* size of region to clear */
 464          width = 4 * (ctx->DrawBuffer->Xmax - ctx->DrawBuffer->Xmin + 1);
 465          height = ctx->DrawBuffer->Ymax - ctx->DrawBuffer->Ymin + 1;
 466          /* ptr to first element to clear */
 467          row = ctx->DrawBuffer->Accum
 468                + 4 * (ctx->DrawBuffer->Ymin * ctx->DrawBuffer->Width
 469                       + ctx->DrawBuffer->Xmin);
 470          for (j=0;j<height;j++) {
 471             for (i=0;i<width;i+=4) {
 472                row[i+0] = r;
 473                row[i+1] = g;
 474                row[i+2] = b;
 475                row[i+3] = a;
 476             }
 477             row += 4 * ctx->DrawBuffer->Width;
 478          }
 479       }
 480       else {
 481          /* clear whole buffer */
 482          if (ctx->Accum.ClearColor[0]==0.0 &&
 483              ctx->Accum.ClearColor[1]==0.0 &&
 484              ctx->Accum.ClearColor[2]==0.0 &&
 485              ctx->Accum.ClearColor[3]==0.0) {
 486             /* Black */
 487             MEMSET( ctx->DrawBuffer->Accum, 0, buffersize * 4 * sizeof(GLaccum) );
 488          }
 489          else {
 490             /* Not black */
 491             GLaccum *acc, r, g, b, a;
 492             GLuint i;
 493
 494             acc = ctx->DrawBuffer->Accum;
 495             r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 496             g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 497             b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 498             a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 499             for (i=0;i<buffersize;i++) {
 500                *acc++ = r;
 501                *acc++ = g;
 502                *acc++ = b;
 503                *acc++ = a;
 504             }
 505          }
 506       }
 507
 508       /* update optimized accum state vars */
 509       if (ctx->Accum.ClearColor[0] == 0.0 && ctx->Accum.ClearColor[1] == 0.0 &&
 510           ctx->Accum.ClearColor[2] == 0.0 && ctx->Accum.ClearColor[3] == 0.0) {
 511 #ifdef USE_OPTIMIZED_ACCUM
 512          ctx->IntegerAccumMode = GL_TRUE;
 513 #else
 514          ctx->IntegerAccumMode = GL_FALSE;
 515 #endif
 516          ctx->IntegerAccumScaler = 0.0;  /* denotes empty accum buffer */
 517       }
 518       else {
 519          ctx->IntegerAccumMode = GL_FALSE;
 520       }
 521    }
 522 }