src/mesa/main/accum.c

   1 /* $Id: accum.c,v 1.29 2000/10/29 18:23:16 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2000  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 "macros.h"
  35 #include "mem.h"
  36 #include "masking.h"
  37 #include "span.h"
  38 #include "state.h"
  39 #include "types.h"
  40 #endif
  41
  42
  43 /*
  44  * Accumulation buffer notes
  45  *
  46  * Normally, accumulation buffer values are GLshorts with values in
  47  * [-32767, 32767] which represent floating point colors in [-1, 1],
  48  * as suggested by the OpenGL specification.
  49  *
  50  * We optimize for the common case used for full-scene antialiasing:
  51  *    // start with accum buffer cleared to zero
  52  *    glAccum(GL_LOAD, w);   // or GL_ACCUM the first image
  53  *    glAccum(GL_ACCUM, w);
  54  *    ...
  55  *    glAccum(GL_ACCUM, w);
  56  *    glAccum(GL_RETURN, 1.0);
  57  * That is, we start with an empty accumulation buffer and accumulate
  58  * n images, each with weight w = 1/n.
  59  * In this scenario, we can simply store unscaled integer values in
  60  * the accum buffer instead of scaled integers.  We'll also keep track
  61  * of the w value so when we do GL_RETURN we simply divide the accumulated
  62  * values by n (=1/w).
  63  * This lets us avoid _many_ int->float->int conversions.
  64  */
  65
  66
  67 #if CHAN_BITS == 8
  68 #define USE_OPTIMIZED_ACCUM   /* enable the optimization */
  69 #endif
  70
  71
  72
  73 void
  74 _mesa_alloc_accum_buffer( GLcontext *ctx )
  75 {
  76    GLint n;
  77
  78    if (ctx->DrawBuffer->Accum) {
  79       FREE( ctx->DrawBuffer->Accum );
  80       ctx->DrawBuffer->Accum = NULL;
  81    }
  82
  83    /* allocate accumulation buffer if not already present */
  84    n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4 * sizeof(GLaccum);
  85    ctx->DrawBuffer->Accum = (GLaccum *) MALLOC( n );
  86    if (!ctx->DrawBuffer->Accum) {
  87       /* unable to setup accumulation buffer */
  88       gl_error( ctx, GL_OUT_OF_MEMORY, "glAccum" );
  89    }
  90 #ifdef USE_OPTIMIZED_ACCUM
  91    ctx->IntegerAccumMode = GL_TRUE;
  92 #else
  93    ctx->IntegerAccumMode = GL_FALSE;
  94 #endif
  95    ctx->IntegerAccumScaler = 0.0;
  96 }
  97
  98
  99
 100 void
 101 _mesa_ClearAccum( GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha )
 102 {
 103    GET_CURRENT_CONTEXT(ctx);
 104    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glAccum");
 105
 106    ctx->Accum.ClearColor[0] = CLAMP( red, -1.0, 1.0 );
 107    ctx->Accum.ClearColor[1] = CLAMP( green, -1.0, 1.0 );
 108    ctx->Accum.ClearColor[2] = CLAMP( blue, -1.0, 1.0 );
 109    ctx->Accum.ClearColor[3] = CLAMP( alpha, -1.0, 1.0 );
 110 }
 111
 112
 113
 114 /*
 115  * This is called when we fall out of optimized/unscaled accum buffer mode.
 116  * That is, we convert each unscaled accum buffer value into a scaled value
 117  * representing the range[-1, 1].
 118  */
 119 static void rescale_accum( GLcontext *ctx )
 120 {
 121    const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4;
 122    const GLfloat fChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 123    const GLfloat s = ctx->IntegerAccumScaler * (32767.0 / fChanMax);
 124    GLaccum *accum = ctx->DrawBuffer->Accum;
 125    GLuint i;
 126
 127    assert(ctx->IntegerAccumMode);
 128    assert(accum);
 129
 130    for (i = 0; i < n; i++) {
 131       accum[i] = (GLaccum) (accum[i] * s);
 132    }
 133
 134    ctx->IntegerAccumMode = GL_FALSE;
 135 }
 136
 137
 138
 139 void
 140 _mesa_Accum( GLenum op, GLfloat value )
 141 {
 142    GET_CURRENT_CONTEXT(ctx);
 143    GLuint xpos, ypos, width, height, width4;
 144    GLfloat acc_scale;
 145    GLchan rgba[MAX_WIDTH][4];
 146    const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
 147    const GLint iChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 148    const GLfloat fChanMax = (1 << (sizeof(GLchan) * 8)) - 1;
 149
 150    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glAccum");
 151
 152    if (ctx->Visual.AccumRedBits == 0 || ctx->DrawBuffer != ctx->ReadBuffer) {
 153       gl_error(ctx, GL_INVALID_OPERATION, "glAccum");
 154       return;
 155    }
 156
 157    if (!ctx->DrawBuffer->Accum) {
 158       _mesa_warning(ctx, "Calling glAccum() without an accumulation buffer (low memory?)");
 159       return;
 160    }
 161
 162    if (sizeof(GLaccum)==1) {
 163       acc_scale = 127.0;
 164    }
 165    else if (sizeof(GLaccum)==2) {
 166       acc_scale = 32767.0;
 167    }
 168    else {
 169       /* sizeof(GLaccum) > 2 (Cray) */
 170       acc_scale = (float) SHRT_MAX;
 171    }
 172
 173    if (ctx->NewState)
 174       gl_update_state( ctx );
 175
 176    /* Determine region to operate upon. */
 177    if (ctx->Scissor.Enabled) {
 178       xpos = ctx->Scissor.X;
 179       ypos = ctx->Scissor.Y;
 180       width = ctx->Scissor.Width;
 181       height = ctx->Scissor.Height;
 182    }
 183    else {
 184       /* whole window */
 185       xpos = 0;
 186       ypos = 0;
 187       width = ctx->DrawBuffer->Width;
 188       height = ctx->DrawBuffer->Height;
 189    }
 190
 191    width4 = 4 * width;
 192
 193    switch (op) {
 194       case GL_ADD:
 195          if (value != 0.0F) {
 196             const GLaccum intVal = (GLaccum) (value * acc_scale);
 197             GLuint j;
 198             /* Leave optimized accum buffer mode */
 199             if (ctx->IntegerAccumMode)
 200                rescale_accum(ctx);
 201             for (j = 0; j < height; j++) {
 202                GLaccum * acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
 203                GLuint i;
 204                for (i = 0; i < width4; i++) {
 205                   acc[i] += intVal;
 206                }
 207                ypos++;
 208             }
 209          }
 210          break;
 211
 212       case GL_MULT:
 213          if (value != 1.0F) {
 214             GLuint j;
 215             /* Leave optimized accum buffer mode */
 216             if (ctx->IntegerAccumMode)
 217                rescale_accum(ctx);
 218             for (j = 0; j < height; j++) {
 219                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
 220                GLuint i;
 221                for (i = 0; i < width4; i++) {
 222                   acc[i] = (GLaccum) ( (GLfloat) acc[i] * value );
 223                }
 224                ypos++;
 225             }
 226          }
 227          break;
 228
 229       case GL_ACCUM:
 230          if (value == 0.0F)
 231             return;
 232
 233          (*ctx->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 234                                        ctx->Pixel.DriverReadBuffer );
 235
 236          /* May have to leave optimized accum buffer mode */
 237          if (ctx->IntegerAccumScaler == 0.0 && value > 0.0 && value <= 1.0)
 238             ctx->IntegerAccumScaler = value;
 239          if (ctx->IntegerAccumMode && value != ctx->IntegerAccumScaler)
 240             rescale_accum(ctx);
 241
 242          RENDER_START(ctx);
 243
 244          if (ctx->IntegerAccumMode) {
 245             /* simply add integer color values into accum buffer */
 246             GLuint j;
 247             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 248             assert(ctx->IntegerAccumScaler > 0.0);
 249             assert(ctx->IntegerAccumScaler <= 1.0);
 250             for (j = 0; j < height; j++) {
 251
 252                GLuint i, i4;
 253                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 254                for (i = i4 = 0; i < width; i++, i4+=4) {
 255                   acc[i4+0] += rgba[i][RCOMP];
 256                   acc[i4+1] += rgba[i][GCOMP];
 257                   acc[i4+2] += rgba[i][BCOMP];
 258                   acc[i4+3] += rgba[i][ACOMP];
 259                }
 260                acc += width4;
 261                ypos++;
 262             }
 263          }
 264          else {
 265             /* scaled integer accum buffer */
 266             const GLfloat rscale = value * acc_scale / fChanMax;
 267             const GLfloat gscale = value * acc_scale / fChanMax;
 268             const GLfloat bscale = value * acc_scale / fChanMax;
 269             const GLfloat ascale = value * acc_scale / fChanMax;
 270             GLuint j;
 271             for (j=0;j<height;j++) {
 272                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 273                GLuint i;
 274                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 275                for (i=0;i<width;i++) {
 276                   *acc += (GLaccum) ( (GLfloat) rgba[i][RCOMP] * rscale );  acc++;
 277                   *acc += (GLaccum) ( (GLfloat) rgba[i][GCOMP] * gscale );  acc++;
 278                   *acc += (GLaccum) ( (GLfloat) rgba[i][BCOMP] * bscale );  acc++;
 279                   *acc += (GLaccum) ( (GLfloat) rgba[i][ACOMP] * ascale );  acc++;
 280                }
 281                ypos++;
 282             }
 283          }
 284          /* restore read buffer = draw buffer (the default) */
 285          (*ctx->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 286                                        ctx->Color.DriverDrawBuffer );
 287          RENDER_FINISH(ctx);
 288          break;
 289
 290       case GL_LOAD:
 291          (*ctx->Driver.SetReadBuffer)( ctx, ctx->ReadBuffer,
 292                                        ctx->Pixel.DriverReadBuffer );
 293
 294          /* This is a change to go into optimized accum buffer mode */
 295          if (value > 0.0 && value <= 1.0) {
 296 #ifdef USE_OPTIMIZED_ACCUM
 297             ctx->IntegerAccumMode = GL_TRUE;
 298 #else
 299             ctx->IntegerAccumMode = GL_FALSE;
 300 #endif
 301             ctx->IntegerAccumScaler = value;
 302          }
 303          else {
 304             ctx->IntegerAccumMode = GL_FALSE;
 305             ctx->IntegerAccumScaler = 0.0;
 306          }
 307
 308          RENDER_START(ctx);
 309          if (ctx->IntegerAccumMode) {
 310             /* just copy values into accum buffer */
 311             GLuint j;
 312             GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 313             assert(ctx->IntegerAccumScaler > 0.0);
 314             assert(ctx->IntegerAccumScaler <= 1.0);
 315             for (j = 0; j < height; j++) {
 316                GLuint i, i4;
 317                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 318                for (i = i4 = 0; i < width; i++, i4 += 4) {
 319                   acc[i4+0] = rgba[i][RCOMP];
 320                   acc[i4+1] = rgba[i][GCOMP];
 321                   acc[i4+2] = rgba[i][BCOMP];
 322                   acc[i4+3] = rgba[i][ACOMP];
 323                }
 324                acc += width4;
 325                ypos++;
 326             }
 327          }
 328          else {
 329             /* scaled integer accum buffer */
 330             const GLfloat rscale = value * acc_scale / fChanMax;
 331             const GLfloat gscale = value * acc_scale / fChanMax;
 332             const GLfloat bscale = value * acc_scale / fChanMax;
 333             const GLfloat ascale = value * acc_scale / fChanMax;
 334             const GLfloat d = 3.0 / acc_scale;
 335             GLuint i, j;
 336             for (j = 0; j < height; j++) {
 337                GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
 338                gl_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
 339                for (i=0;i<width;i++) {
 340                   *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale + d);
 341                   *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale + d);
 342                   *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale + d);
 343                   *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale + d);
 344                }
 345                ypos++;
 346             }
 347          }
 348
 349          /* restore read buffer = draw buffer (the default) */
 350          (*ctx->Driver.SetReadBuffer)( ctx, ctx->DrawBuffer,
 351                                        ctx->Color.DriverDrawBuffer );
 352          RENDER_FINISH(ctx);
 353          break;
 354
 355       case GL_RETURN:
 356          /* May have to leave optimized accum buffer mode */
 357          if (ctx->IntegerAccumMode && value != 1.0)
 358             rescale_accum(ctx);
 359
 360          RENDER_START(ctx);
 361          if (ctx->IntegerAccumMode && ctx->IntegerAccumScaler > 0) {
 362             /* build lookup table to avoid many floating point multiplies */
 363             static GLchan multTable[32768];
 364             static GLfloat prevMult = 0.0;
 365             const GLfloat mult = ctx->IntegerAccumScaler;
 366             const GLint max = MIN2((GLint) (256 / mult), 32767);
 367             GLuint j;
 368             if (mult != prevMult) {
 369                for (j = 0; j < max; j++)
 370                   multTable[j] = (GLint) ((GLfloat) j * mult + 0.5F);
 371                prevMult = mult;
 372             }
 373
 374             assert(ctx->IntegerAccumScaler > 0.0);
 375             assert(ctx->IntegerAccumScaler <= 1.0);
 376             for (j = 0; j < height; j++) {
 377                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 378                GLuint i, i4;
 379                for (i = i4 = 0; i < width; i++, i4 += 4) {
 380                   ASSERT(acc[i4+0] < max);
 381                   ASSERT(acc[i4+1] < max);
 382                   ASSERT(acc[i4+2] < max);
 383                   ASSERT(acc[i4+3] < max);
 384                   rgba[i][RCOMP] = multTable[acc[i4+0]];
 385                   rgba[i][GCOMP] = multTable[acc[i4+1]];
 386                   rgba[i][BCOMP] = multTable[acc[i4+2]];
 387                   rgba[i][ACOMP] = multTable[acc[i4+3]];
 388                }
 389                if (colorMask != 0xffffffff) {
 390                   _mesa_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 391                }
 392                (*ctx->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 393                                              (const GLchan (*)[4])rgba, NULL );
 394                ypos++;
 395             }
 396          }
 397          else {
 398             const GLfloat rscale = value / acc_scale * fChanMax;
 399             const GLfloat gscale = value / acc_scale * fChanMax;
 400             const GLfloat bscale = value / acc_scale * fChanMax;
 401             const GLfloat ascale = value / acc_scale * fChanMax;
 402             GLuint i, j;
 403             for (j=0;j<height;j++) {
 404                const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
 405                for (i=0;i<width;i++) {
 406                   GLint r, g, b, a;
 407                   r = (GLint) ( (GLfloat) (*acc++) * rscale + 0.5F );
 408                   g = (GLint) ( (GLfloat) (*acc++) * gscale + 0.5F );
 409                   b = (GLint) ( (GLfloat) (*acc++) * bscale + 0.5F );
 410                   a = (GLint) ( (GLfloat) (*acc++) * ascale + 0.5F );
 411                   rgba[i][RCOMP] = CLAMP( r, 0, iChanMax );
 412                   rgba[i][GCOMP] = CLAMP( g, 0, iChanMax );
 413                   rgba[i][BCOMP] = CLAMP( b, 0, iChanMax );
 414                   rgba[i][ACOMP] = CLAMP( a, 0, iChanMax );
 415                }
 416                if (colorMask != 0xffffffff) {
 417                   _mesa_mask_rgba_span( ctx, width, xpos, ypos, rgba );
 418                }
 419                (*ctx->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
 420                                              (const GLchan (*)[4])rgba, NULL );
 421                ypos++;
 422             }
 423          }
 424          RENDER_FINISH(ctx);
 425          break;
 426
 427       default:
 428          gl_error( ctx, GL_INVALID_ENUM, "glAccum" );
 429    }
 430 }
 431
 432
 433
 434 /*
 435  * Clear the accumulation Buffer.
 436  */
 437 void
 438 _mesa_clear_accum_buffer( GLcontext *ctx )
 439 {
 440    GLuint buffersize;
 441    GLfloat acc_scale;
 442
 443    if (ctx->Visual.AccumRedBits==0) {
 444       /* No accumulation buffer! */
 445       return;
 446    }
 447
 448    if (sizeof(GLaccum)==1) {
 449       acc_scale = 127.0;
 450    }
 451    else if (sizeof(GLaccum)==2) {
 452       acc_scale = 32767.0;
 453    }
 454    else {
 455       /* sizeof(GLaccum) > 2 (Cray) */
 456       acc_scale = (float) SHRT_MAX;
 457    }
 458
 459    /* number of pixels */
 460    buffersize = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
 461
 462    if (!ctx->DrawBuffer->Accum) {
 463       /* try to alloc accumulation buffer */
 464       ctx->DrawBuffer->Accum = (GLaccum *)
 465                            MALLOC( buffersize * 4 * sizeof(GLaccum) );
 466    }
 467
 468    if (ctx->DrawBuffer->Accum) {
 469       if (ctx->Scissor.Enabled) {
 470          /* Limit clear to scissor box */
 471          GLaccum r, g, b, a;
 472          GLint i, j;
 473          GLint width, height;
 474          GLaccum *row;
 475          r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 476          g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 477          b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 478          a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 479          /* size of region to clear */
 480          width = 4 * (ctx->DrawBuffer->Xmax - ctx->DrawBuffer->Xmin);
 481          height = ctx->DrawBuffer->Ymax - ctx->DrawBuffer->Ymin;
 482          /* ptr to first element to clear */
 483          row = ctx->DrawBuffer->Accum
 484                + 4 * (ctx->DrawBuffer->Ymin * ctx->DrawBuffer->Width
 485                       + ctx->DrawBuffer->Xmin);
 486          for (j=0;j<height;j++) {
 487             for (i=0;i<width;i+=4) {
 488                row[i+0] = r;
 489                row[i+1] = g;
 490                row[i+2] = b;
 491                row[i+3] = a;
 492             }
 493             row += 4 * ctx->DrawBuffer->Width;
 494          }
 495       }
 496       else {
 497          /* clear whole buffer */
 498          if (ctx->Accum.ClearColor[0]==0.0 &&
 499              ctx->Accum.ClearColor[1]==0.0 &&
 500              ctx->Accum.ClearColor[2]==0.0 &&
 501              ctx->Accum.ClearColor[3]==0.0) {
 502             /* Black */
 503             BZERO( ctx->DrawBuffer->Accum, buffersize * 4 * sizeof(GLaccum) );
 504          }
 505          else {
 506             /* Not black */
 507             GLaccum *acc, r, g, b, a;
 508             GLuint i;
 509
 510             acc = ctx->DrawBuffer->Accum;
 511             r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
 512             g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
 513             b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
 514             a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
 515             for (i=0;i<buffersize;i++) {
 516                *acc++ = r;
 517                *acc++ = g;
 518                *acc++ = b;
 519                *acc++ = a;
 520             }
 521          }
 522       }
 523
 524       /* update optimized accum state vars */
 525       if (ctx->Accum.ClearColor[0] == 0.0 && ctx->Accum.ClearColor[1] == 0.0 &&
 526           ctx->Accum.ClearColor[2] == 0.0 && ctx->Accum.ClearColor[3] == 0.0) {
 527 #ifdef USE_OPTIMIZED_ACCUM
 528          ctx->IntegerAccumMode = GL_TRUE;
 529 #else
 530          ctx->IntegerAccumMode = GL_FALSE;
 531 #endif
 532          ctx->IntegerAccumScaler = 0.0;  /* denotes empty accum buffer */
 533       }
 534       else {
 535          ctx->IntegerAccumMode = GL_FALSE;
 536       }
 537    }
 538 }