src/mesa/swrast/s_zoom.c

   1 /* $Id: s_zoom.c,v 1.19 2002/12/05 04:48:53 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  5.1
   6  *
   7  * Copyright (C) 1999-2002  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 #include "glheader.h"
  28 #include "macros.h"
  29 #include "imports.h"
  30 #include "colormac.h"
  31
  32 #include "s_context.h"
  33 #include "s_span.h"
  34 #include "s_stencil.h"
  35 #include "s_zoom.h"
  36
  37
  38 /*
  39  * Helper function called from _mesa_write_zoomed_rgba/rgb/index_span().
  40  */
  41 static void
  42 zoom_span( GLcontext *ctx, const struct sw_span *span,
  43            const GLvoid *src, GLint y0, GLenum format, GLint skipPixels )
  44 {
  45    GLint r0, r1, row;
  46    GLint c0, c1, skipCol;
  47    GLint i, j;
  48    const GLuint maxWidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
  49    GLchan rgbaSave[MAX_WIDTH][4];
  50    GLuint indexSave[MAX_WIDTH];
  51    const GLchan (*rgba)[4] = (const GLchan (*)[4]) src;
  52    const GLchan (*rgb)[3] = (const GLchan (*)[3]) src;
  53    const GLuint *indexes = (const GLuint *) src;
  54    struct sw_span zoomed;
  55    struct span_arrays zoomed_arrays;  /* this is big! */
  56
  57    /* no pixel arrays! */
  58    ASSERT((span->arrayMask & SPAN_XY) == 0);
  59    ASSERT(span->primitive == GL_BITMAP);
  60
  61    INIT_SPAN(zoomed, GL_BITMAP, 0, 0, 0);
  62    zoomed.array = &zoomed_arrays;
  63
  64    zoomed.z = span->z;
  65    zoomed.zStep = span->z;
  66    zoomed.fog = span->fog;
  67    zoomed.fogStep = span->fogStep;
  68    if (format == GL_RGBA || format == GL_RGB) {
  69       zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
  70       zoomed.arrayMask |= SPAN_RGBA;
  71    }
  72    else if (format == GL_COLOR_INDEX) {
  73       zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
  74       zoomed.arrayMask |= SPAN_INDEX;
  75    }
  76
  77    /*
  78     * Compute which columns to draw: [c0, c1)
  79     */
  80 #if 0
  81    c0 = (GLint) span->x;
  82    c1 = (GLint) (span->x + span->end * ctx->Pixel.ZoomX);
  83 #else
  84    c0 = (GLint) span->x + skipPixels * ctx->Pixel.ZoomX;
  85    c1 = (GLint) (span->x + (skipPixels + span->end) * ctx->Pixel.ZoomX);
  86 #endif
  87    if (c0 == c1) {
  88       return;
  89    }
  90    else if (c1 < c0) {
  91       /* swap */
  92       GLint ctmp = c1;
  93       c1 = c0;
  94       c0 = ctmp;
  95    }
  96    if (c0 < 0) {
  97       zoomed.x = 0;
  98       zoomed.start = 0;
  99       zoomed.end = c1;
 100       skipCol = -c0;
 101    }
 102    else {
 103       zoomed.x = c0;
 104       zoomed.start = 0;
 105       zoomed.end = c1 - c0;
 106       skipCol = 0;
 107    }
 108    if (zoomed.end > maxWidth)
 109       zoomed.end = maxWidth;
 110
 111    /*
 112     * Compute which rows to draw: [r0, r1)
 113     */
 114    row = span->y - y0;
 115    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 116    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 117    if (r0 == r1) {
 118       return;
 119    }
 120    else if (r1 < r0) {
 121       /* swap */
 122       GLint rtmp = r1;
 123       r1 = r0;
 124       r0 = rtmp;
 125    }
 126
 127    ASSERT(r0 < r1);
 128    ASSERT(c0 < c1);
 129
 130    /*
 131     * Trivial clip rejection testing.
 132     */
 133    if (r1 < 0) /* below window */
 134       return;
 135    if (r0 >= (GLint) ctx->DrawBuffer->Height) /* above window */
 136       return;
 137    if (c1 < 0) /* left of window */
 138       return;
 139    if (c0 >= (GLint) ctx->DrawBuffer->Width) /* right of window */
 140       return;
 141
 142    /* zoom the span horizontally */
 143    if (format == GL_RGBA) {
 144       if (ctx->Pixel.ZoomX == -1.0F) {
 145          /* common case */
 146          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 147             i = span->end - (j + skipCol) - 1;
 148             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 149          }
 150       }
 151       else {
 152          /* general solution */
 153          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 154          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 155             i = (GLint) ((j + skipCol) * xscale);
 156             if (ctx->Pixel.ZoomX < 0.0) {
 157                ASSERT(i <= 0);
 158                i = span->end + i - 1;
 159             }
 160             ASSERT(i >= 0);
 161             ASSERT(i < span->end);
 162             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 163          }
 164       }
 165    }
 166    else if (format == GL_RGB) {
 167       if (ctx->Pixel.ZoomX == -1.0F) {
 168          /* common case */
 169          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 170             i = span->end - (j + skipCol) - 1;
 171             zoomed.array->rgba[j][0] = rgb[i][0];
 172             zoomed.array->rgba[j][1] = rgb[i][1];
 173             zoomed.array->rgba[j][2] = rgb[i][2];
 174             zoomed.array->rgba[j][3] = CHAN_MAX;
 175          }
 176       }
 177       else {
 178          /* general solution */
 179          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 180          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 181             i = (GLint) ((j + skipCol) * xscale);
 182             if (ctx->Pixel.ZoomX < 0.0) {
 183                ASSERT(i <= 0);
 184                i = span->end + i - 1;
 185             }
 186             ASSERT(i >= 0);
 187             ASSERT(i < span->end);
 188             zoomed.array->rgba[j][0] = rgb[i][0];
 189             zoomed.array->rgba[j][1] = rgb[i][1];
 190             zoomed.array->rgba[j][2] = rgb[i][2];
 191             zoomed.array->rgba[j][3] = CHAN_MAX;
 192          }
 193       }
 194    }
 195    else if (format == GL_COLOR_INDEX) {
 196       if (ctx->Pixel.ZoomX == -1.0F) {
 197          /* common case */
 198          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 199             i = span->end - (j + skipCol) - 1;
 200             zoomed.array->index[j] = indexes[i];
 201          }
 202       }
 203       else {
 204          /* general solution */
 205          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 206          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 207             i = (GLint) ((j + skipCol) * xscale);
 208             if (ctx->Pixel.ZoomX < 0.0) {
 209                ASSERT(i <= 0);
 210                i = span->end + i - 1;
 211             }
 212             ASSERT(i >= 0);
 213             ASSERT(i < span->end);
 214             zoomed.array->index[j] = indexes[i];
 215          }
 216       }
 217    }
 218
 219    /* write the span in rows [r0, r1) */
 220    if (format == GL_RGBA || format == GL_RGB) {
 221       /* Writing the span may modify the colors, so make a backup now if we're
 222        * going to call _mesa_write_zoomed_span() more than once.
 223        */
 224       if (r1 - r0 > 1) {
 225          MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * 4 * sizeof(GLchan));
 226       }
 227       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 228          _mesa_write_rgba_span(ctx, &zoomed);
 229          if (r1 - r0 > 1) {
 230             /* restore the colors */
 231             MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
 232          }
 233       }
 234    }
 235    else if (format == GL_COLOR_INDEX) {
 236       if (r1 - r0 > 1) {
 237          MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
 238       }
 239       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 240          _mesa_write_index_span(ctx, &zoomed);
 241          if (r1 - r0 > 1) {
 242             /* restore the colors */
 243             MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
 244          }
 245       }
 246    }
 247 }
 248
 249
 250 void
 251 _mesa_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
 252                               CONST GLchan rgba[][4], GLint y0,
 253                               GLint skipPixels )
 254 {
 255    zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA, skipPixels);
 256 }
 257
 258
 259 void
 260 _mesa_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
 261                              CONST GLchan rgb[][3], GLint y0,
 262                              GLint skipPixels )
 263 {
 264    zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB, skipPixels);
 265 }
 266
 267
 268 void
 269 _mesa_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
 270                                GLint y0, GLint skipPixels )
 271 {
 272   zoom_span(ctx, span, (const GLvoid *) span->array->index, y0,
 273             GL_COLOR_INDEX, skipPixels);
 274 }
 275
 276
 277 /*
 278  * As above, but write stencil values.
 279  */
 280 void
 281 _mesa_write_zoomed_stencil_span( GLcontext *ctx,
 282                                  GLuint n, GLint x, GLint y,
 283                                  const GLstencil stencil[], GLint y0,
 284                                  GLint skipPixels )
 285 {
 286    GLint m;
 287    GLint r0, r1, row, r;
 288    GLint i, j, skipcol;
 289    GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
 290    GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
 291
 292    (void) skipPixels;  /* XXX this shouldn't be ignored */
 293
 294    /* compute width of output row */
 295    m = (GLint) ABSF( n * ctx->Pixel.ZoomX );
 296    if (m==0) {
 297       return;
 298    }
 299    if (ctx->Pixel.ZoomX<0.0) {
 300       /* adjust x coordinate for left/right mirroring */
 301       x = x - m;
 302    }
 303
 304    /* compute which rows to draw */
 305    row = y - y0;
 306    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 307    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 308    if (r0==r1) {
 309       return;
 310    }
 311    else if (r1<r0) {
 312       GLint rtmp = r1;
 313       r1 = r0;
 314       r0 = rtmp;
 315    }
 316
 317    /* return early if r0...r1 is above or below window */
 318    if (r0<0 && r1<0) {
 319       /* below window */
 320       return;
 321    }
 322    if (r0 >= (GLint) ctx->DrawBuffer->Height &&
 323        r1 >= (GLint) ctx->DrawBuffer->Height) {
 324       /* above window */
 325       return;
 326    }
 327
 328    /* check if left edge is outside window */
 329    skipcol = 0;
 330    if (x<0) {
 331       skipcol = -x;
 332       m += x;
 333    }
 334    /* make sure span isn't too long or short */
 335    if (m>maxwidth) {
 336       m = maxwidth;
 337    }
 338    else if (m<=0) {
 339       return;
 340    }
 341
 342    ASSERT( m <= MAX_WIDTH );
 343
 344    /* zoom the span horizontally */
 345    if (ctx->Pixel.ZoomX==-1.0F) {
 346       /* n==m */
 347       for (j=0;j<m;j++) {
 348          i = n - (j+skipcol) - 1;
 349          zstencil[j] = stencil[i];
 350       }
 351    }
 352    else {
 353       GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 354       for (j=0;j<m;j++) {
 355          i = (GLint) ((j+skipcol) * xscale);
 356          if (i<0)  i = n + i - 1;
 357          zstencil[j] = stencil[i];
 358       }
 359    }
 360
 361    /* write the span */
 362    for (r=r0; r<r1; r++) {
 363       _mesa_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
 364    }
 365 }