src/mesa/swrast/s_zoom.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  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 #include "glheader.h"
  26 #include "macros.h"
  27 #include "imports.h"
  28 #include "colormac.h"
  29
  30 #include "s_context.h"
  31 #include "s_span.h"
  32 #include "s_stencil.h"
  33 #include "s_zoom.h"
  34
  35
  36 /*
  37  * Helper function called from _swrast_write_zoomed_rgba/rgb/index_span().
  38  */
  39 static void
  40 zoom_span( GLcontext *ctx, const struct sw_span *span,
  41            const GLvoid *src, GLint y0, GLenum format, GLint skipPixels )
  42 {
  43    GLint r0, r1, row;
  44    GLint c0, c1, skipCol;
  45    GLint i, j;
  46    const GLuint maxWidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
  47    struct sw_span zoomed;
  48    struct span_arrays zoomed_arrays;  /* this is big! */
  49
  50    /* no pixel arrays! must be horizontal spans. */
  51    ASSERT((span->arrayMask & SPAN_XY) == 0);
  52    ASSERT(span->primitive == GL_BITMAP);
  53
  54    INIT_SPAN(zoomed, GL_BITMAP, 0, 0, 0);
  55    zoomed.array = &zoomed_arrays;
  56
  57    /* copy fog interp info */
  58    zoomed.fog = span->fog;
  59    zoomed.fogStep = span->fogStep;
  60    /* XXX copy texcoord info? */
  61
  62    if (format == GL_RGBA || format == GL_RGB) {
  63       /* copy Z info */
  64       zoomed.z = span->z;
  65       zoomed.zStep = span->zStep;
  66       /* we'll generate an array of colorss */
  67       zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
  68       zoomed.arrayMask |= SPAN_RGBA;
  69    }
  70    else if (format == GL_COLOR_INDEX) {
  71       /* copy Z info */
  72       zoomed.z = span->z;
  73       zoomed.zStep = span->zStep;
  74       /* we'll generate an array of color indexes */
  75       zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
  76       zoomed.arrayMask |= SPAN_INDEX;
  77    }
  78    else {
  79       assert(format == GL_DEPTH_COMPONENT);
  80       /* Copy color info */
  81       zoomed.red = span->red;
  82       zoomed.green = span->green;
  83       zoomed.blue = span->blue;
  84       zoomed.alpha = span->alpha;
  85       zoomed.redStep = span->redStep;
  86       zoomed.greenStep = span->greenStep;
  87       zoomed.blueStep = span->blueStep;
  88       zoomed.alphaStep = span->alphaStep;
  89       /* we'll generate an array of depth values */
  90       zoomed.interpMask = span->interpMask & ~SPAN_Z;
  91       zoomed.arrayMask |= SPAN_Z;
  92    }
  93
  94    /*
  95     * Compute which columns to draw: [c0, c1)
  96     */
  97    c0 = (GLint) (span->x + skipPixels * ctx->Pixel.ZoomX);
  98    c1 = (GLint) (span->x + (skipPixels + span->end) * ctx->Pixel.ZoomX);
  99    if (c0 == c1) {
 100       return;
 101    }
 102    else if (c1 < c0) {
 103       /* swap */
 104       GLint ctmp = c1;
 105       c1 = c0;
 106       c0 = ctmp;
 107    }
 108    if (c0 < 0) {
 109       zoomed.x = 0;
 110       zoomed.start = 0;
 111       zoomed.end = c1;
 112       skipCol = -c0;
 113    }
 114    else {
 115       zoomed.x = c0;
 116       zoomed.start = 0;
 117       zoomed.end = c1 - c0;
 118       skipCol = 0;
 119    }
 120    if (zoomed.end > maxWidth)
 121       zoomed.end = maxWidth;
 122
 123    /*
 124     * Compute which rows to draw: [r0, r1)
 125     */
 126    row = span->y - y0;
 127    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 128    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 129    if (r0 == r1) {
 130       return;
 131    }
 132    else if (r1 < r0) {
 133       /* swap */
 134       GLint rtmp = r1;
 135       r1 = r0;
 136       r0 = rtmp;
 137    }
 138
 139    ASSERT(r0 < r1);
 140    ASSERT(c0 < c1);
 141
 142    /*
 143     * Trivial clip rejection testing.
 144     */
 145    if (r1 < 0) /* below window */
 146       return;
 147    if (r0 >= (GLint) ctx->DrawBuffer->Height) /* above window */
 148       return;
 149    if (c1 < 0) /* left of window */
 150       return;
 151    if (c0 >= (GLint) ctx->DrawBuffer->Width) /* right of window */
 152       return;
 153
 154    /* zoom the span horizontally */
 155    if (format == GL_RGBA) {
 156       const GLchan (*rgba)[4] = (const GLchan (*)[4]) src;
 157       if (ctx->Pixel.ZoomX == -1.0F) {
 158          /* common case */
 159          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 160             i = span->end - (j + skipCol) - 1;
 161             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 162          }
 163       }
 164       else {
 165          /* general solution */
 166          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 167          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 168             i = (GLint) ((j + skipCol) * xscale);
 169             if (ctx->Pixel.ZoomX < 0.0) {
 170                ASSERT(i <= 0);
 171                i = span->end + i - 1;
 172             }
 173             ASSERT(i >= 0);
 174             ASSERT(i < (GLint)  span->end);
 175             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 176          }
 177       }
 178    }
 179    else if (format == GL_RGB) {
 180       const GLchan (*rgb)[3] = (const GLchan (*)[3]) src;
 181       if (ctx->Pixel.ZoomX == -1.0F) {
 182          /* common case */
 183          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 184             i = span->end - (j + skipCol) - 1;
 185             zoomed.array->rgba[j][0] = rgb[i][0];
 186             zoomed.array->rgba[j][1] = rgb[i][1];
 187             zoomed.array->rgba[j][2] = rgb[i][2];
 188             zoomed.array->rgba[j][3] = CHAN_MAX;
 189          }
 190       }
 191       else {
 192          /* general solution */
 193          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 194          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 195             i = (GLint) ((j + skipCol) * xscale);
 196             if (ctx->Pixel.ZoomX < 0.0) {
 197                ASSERT(i <= 0);
 198                i = span->end + i - 1;
 199             }
 200             ASSERT(i >= 0);
 201             ASSERT(i < (GLint) span->end);
 202             zoomed.array->rgba[j][0] = rgb[i][0];
 203             zoomed.array->rgba[j][1] = rgb[i][1];
 204             zoomed.array->rgba[j][2] = rgb[i][2];
 205             zoomed.array->rgba[j][3] = CHAN_MAX;
 206          }
 207       }
 208    }
 209    else if (format == GL_COLOR_INDEX) {
 210       const GLuint *indexes = (const GLuint *) src;
 211       if (ctx->Pixel.ZoomX == -1.0F) {
 212          /* common case */
 213          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 214             i = span->end - (j + skipCol) - 1;
 215             zoomed.array->index[j] = indexes[i];
 216          }
 217       }
 218       else {
 219          /* general solution */
 220          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 221          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 222             i = (GLint) ((j + skipCol) * xscale);
 223             if (ctx->Pixel.ZoomX < 0.0) {
 224                ASSERT(i <= 0);
 225                i = span->end + i - 1;
 226             }
 227             ASSERT(i >= 0);
 228             ASSERT(i < (GLint) span->end);
 229             zoomed.array->index[j] = indexes[i];
 230          }
 231       }
 232    }
 233    else {
 234       const GLuint *zValues = (const GLuint *) src;
 235       assert(format == GL_DEPTH_COMPONENT);
 236       if (ctx->Pixel.ZoomX == -1.0F) {
 237          /* common case */
 238          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 239             i = span->end - (j + skipCol) - 1;
 240             zoomed.array->z[j] = zValues[i];
 241          }
 242       }
 243       else {
 244          /* general solution */
 245          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 246          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 247             i = (GLint) ((j + skipCol) * xscale);
 248             if (ctx->Pixel.ZoomX < 0.0) {
 249                ASSERT(i <= 0);
 250                i = span->end + i - 1;
 251             }
 252             ASSERT(i >= 0);
 253             ASSERT(i < (GLint) span->end);
 254             zoomed.array->z[j] = zValues[i];
 255          }
 256       }
 257       /* Now, fall into either the RGB or COLOR_INDEX path below */
 258       if (ctx->Visual.rgbMode)
 259          format = GL_RGBA;
 260       else
 261          format = GL_COLOR_INDEX;
 262    }
 263
 264
 265    /* write the span in rows [r0, r1) */
 266    if (format == GL_RGBA || format == GL_RGB) {
 267       /* Writing the span may modify the colors, so make a backup now if we're
 268        * going to call _swrast_write_zoomed_span() more than once.
 269        * Also, clipping may change the span end value, so store it as well.
 270        */
 271       GLchan rgbaSave[MAX_WIDTH][4];
 272       const GLint end = zoomed.end; /* save */
 273       if (r1 - r0 > 1) {
 274          MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * 4 * sizeof(GLchan));
 275       }
 276       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 277          _swrast_write_rgba_span(ctx, &zoomed);
 278          zoomed.end = end;  /* restore */
 279          if (r1 - r0 > 1) {
 280             /* restore the colors */
 281             MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
 282          }
 283       }
 284    }
 285    else if (format == GL_COLOR_INDEX) {
 286       GLuint indexSave[MAX_WIDTH];
 287       const GLint end = zoomed.end; /* save */
 288       if (r1 - r0 > 1) {
 289          MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
 290       }
 291       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 292          _swrast_write_index_span(ctx, &zoomed);
 293          zoomed.end = end;  /* restore */
 294          if (r1 - r0 > 1) {
 295             /* restore the colors */
 296             MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
 297          }
 298       }
 299    }
 300 }
 301
 302
 303 void
 304 _swrast_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
 305                               CONST GLchan rgba[][4], GLint y0,
 306                               GLint skipPixels )
 307 {
 308    zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA, skipPixels);
 309 }
 310
 311
 312 void
 313 _swrast_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
 314                              CONST GLchan rgb[][3], GLint y0,
 315                              GLint skipPixels )
 316 {
 317    zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB, skipPixels);
 318 }
 319
 320
 321 void
 322 _swrast_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
 323                                GLint y0, GLint skipPixels )
 324 {
 325    zoom_span(ctx, span, (const GLvoid *) span->array->index, y0,
 326              GL_COLOR_INDEX, skipPixels);
 327 }
 328
 329
 330 void
 331 _swrast_write_zoomed_depth_span( GLcontext *ctx, const struct sw_span *span,
 332                                  GLint y0, GLint skipPixels )
 333 {
 334    zoom_span(ctx, span, (const GLvoid *) span->array->z, y0,
 335              GL_DEPTH_COMPONENT, skipPixels);
 336 }
 337
 338
 339 /*
 340  * As above, but write stencil values.
 341  */
 342 void
 343 _swrast_write_zoomed_stencil_span( GLcontext *ctx,
 344                                  GLuint n, GLint x, GLint y,
 345                                  const GLstencil stencil[], GLint y0,
 346                                  GLint skipPixels )
 347 {
 348    GLint m;
 349    GLint r0, r1, row, r;
 350    GLint i, j, skipcol;
 351    GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
 352    GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
 353
 354    (void) skipPixels;  /* XXX this shouldn't be ignored */
 355
 356    /* compute width of output row */
 357    m = (GLint) FABSF( n * ctx->Pixel.ZoomX );
 358    if (m==0) {
 359       return;
 360    }
 361    if (ctx->Pixel.ZoomX<0.0) {
 362       /* adjust x coordinate for left/right mirroring */
 363       x = x - m;
 364    }
 365
 366    /* compute which rows to draw */
 367    row = y - y0;
 368    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 369    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 370    if (r0==r1) {
 371       return;
 372    }
 373    else if (r1<r0) {
 374       GLint rtmp = r1;
 375       r1 = r0;
 376       r0 = rtmp;
 377    }
 378
 379    /* return early if r0...r1 is above or below window */
 380    if (r0<0 && r1<0) {
 381       /* below window */
 382       return;
 383    }
 384    if (r0 >= (GLint) ctx->DrawBuffer->Height &&
 385        r1 >= (GLint) ctx->DrawBuffer->Height) {
 386       /* above window */
 387       return;
 388    }
 389
 390    /* check if left edge is outside window */
 391    skipcol = 0;
 392    if (x<0) {
 393       skipcol = -x;
 394       m += x;
 395    }
 396    /* make sure span isn't too long or short */
 397    if (m>maxwidth) {
 398       m = maxwidth;
 399    }
 400    else if (m<=0) {
 401       return;
 402    }
 403
 404    ASSERT( m <= MAX_WIDTH );
 405
 406    /* zoom the span horizontally */
 407    if (ctx->Pixel.ZoomX==-1.0F) {
 408       /* n==m */
 409       for (j=0;j<m;j++) {
 410          i = n - (j+skipcol) - 1;
 411          zstencil[j] = stencil[i];
 412       }
 413    }
 414    else {
 415       GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 416       for (j=0;j<m;j++) {
 417          i = (GLint) ((j+skipcol) * xscale);
 418          if (i<0)  i = n + i - 1;
 419          zstencil[j] = stencil[i];
 420       }
 421    }
 422
 423    /* write the span */
 424    for (r=r0; r<r1; r++) {
 425       _swrast_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
 426    }
 427 }