src/mesa/swrast/s_zoom.c

   1 /* $Id: s_zoom.c,v 1.14 2002/04/12 15:39:59 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  4.1
   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 "mem.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 )
  44 {
  45    GLint r0, r1, row;
  46    GLint c0, c1, skipCol;
  47    GLint i, j;
  48    const GLint maxWidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
  49    GLchan rgbaSave[MAX_WIDTH][4];
  50    GLuint indexSave[MAX_WIDTH];
  51    struct sw_span zoomed;
  52    const GLchan (*rgba)[4] = (const GLchan (*)[4]) src;
  53    const GLchan (*rgb)[3] = (const GLchan (*)[3]) src;
  54    const GLuint *indexes = (const GLuint *) src;
  55
  56    /* no pixel arrays! */
  57    ASSERT((span->arrayMask & SPAN_XY) == 0);
  58    ASSERT(span->primitive == GL_BITMAP);
  59
  60    INIT_SPAN(zoomed, GL_BITMAP, 0, 0, 0);
  61    if (format == GL_RGBA || format == GL_RGB) {
  62       zoomed.z = span->z;
  63       zoomed.zStep = span->z;
  64       zoomed.fog = span->fog;
  65       zoomed.fogStep = span->fogStep;
  66       zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
  67       zoomed.arrayMask |= SPAN_RGBA;
  68    }
  69    else if (format == GL_COLOR_INDEX) {
  70       zoomed.z = span->z;
  71       zoomed.zStep = span->z;
  72       zoomed.fog = span->fog;
  73       zoomed.fogStep = span->fogStep;
  74       zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
  75       zoomed.arrayMask |= SPAN_INDEX;
  76    }
  77
  78    /*
  79     * Compute which columns to draw: [c0, c1)
  80     */
  81    c0 = (GLint) span->x;
  82    c1 = (GLint) (span->x + span->end * ctx->Pixel.ZoomX);
  83    if (c0 == c1) {
  84       return;
  85    }
  86    else if (c1 < c0) {
  87       /* swap */
  88       GLint ctmp = c1;
  89       c1 = c0;
  90       c0 = ctmp;
  91    }
  92    if (c0 < 0) {
  93       zoomed.x = 0;
  94       zoomed.start = 0;
  95       zoomed.end = c1;
  96       skipCol = -c0;
  97    }
  98    else {
  99       zoomed.x = c0;
 100       zoomed.start = 0;
 101       zoomed.end = c1 - c0;
 102       skipCol = 0;
 103    }
 104    if (zoomed.end > maxWidth)
 105       zoomed.end = maxWidth;
 106
 107    /*
 108     * Compute which rows to draw: [r0, r1)
 109     */
 110    row = span->y - y0;
 111    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 112    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 113    if (r0 == r1) {
 114       return;
 115    }
 116    else if (r1 < r0) {
 117       /* swap */
 118       GLint rtmp = r1;
 119       r1 = r0;
 120       r0 = rtmp;
 121    }
 122
 123    ASSERT(r0 < r1);
 124    ASSERT(c0 < c1);
 125
 126    /*
 127     * Trivial clip rejection testing.
 128     */
 129    if (r1 < 0) /* below window */
 130       return;
 131    if (r0 >= ctx->DrawBuffer->Height) /* above window */
 132       return;
 133    if (c1 < 0) /* left of window */
 134       return;
 135    if (c0 >= ctx->DrawBuffer->Width) /* right of window */
 136       return;
 137
 138    /* zoom the span horizontally */
 139    if (format == GL_RGBA) {
 140       if (ctx->Pixel.ZoomX == -1.0F) {
 141          /* common case */
 142          for (j = zoomed.start; j < zoomed.end; j++) {
 143             i = span->end - (j + skipCol) - 1;
 144             COPY_CHAN4(zoomed.color.rgba[j], rgba[i]);
 145          }
 146       }
 147       else {
 148          /* general solution */
 149          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 150          for (j = zoomed.start; j < zoomed.end; j++) {
 151             i = (GLint) ((j + skipCol) * xscale);
 152             if (i < 0)
 153                i = span->end + i - 1;
 154             COPY_CHAN4(zoomed.color.rgba[j], rgba[i]);
 155          }
 156       }
 157    }
 158    else if (format == GL_RGB) {
 159       if (ctx->Pixel.ZoomX == -1.0F) {
 160          /* common case */
 161          for (j = zoomed.start; j < zoomed.end; j++) {
 162             i = span->end - (j + skipCol) - 1;
 163             zoomed.color.rgba[j][0] = rgb[i][0];
 164             zoomed.color.rgba[j][1] = rgb[i][1];
 165             zoomed.color.rgba[j][2] = rgb[i][2];
 166             zoomed.color.rgba[j][3] = CHAN_MAX;
 167          }
 168       }
 169       else {
 170          /* general solution */
 171          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 172          for (j = zoomed.start; j < zoomed.end; j++) {
 173             i = (GLint) ((j + skipCol) * xscale);
 174             if (i < 0)
 175                i = span->end + i - 1;
 176             zoomed.color.rgba[j][0] = rgb[i][0];
 177             zoomed.color.rgba[j][1] = rgb[i][1];
 178             zoomed.color.rgba[j][2] = rgb[i][2];
 179             zoomed.color.rgba[j][3] = CHAN_MAX;
 180          }
 181       }
 182    }
 183    else if (format == GL_COLOR_INDEX) {
 184       if (ctx->Pixel.ZoomX == -1.0F) {
 185          /* common case */
 186          for (j = zoomed.start; j < zoomed.end; j++) {
 187             i = span->end - (j + skipCol) - 1;
 188             zoomed.color.index[j] = indexes[i];
 189          }
 190       }
 191       else {
 192          /* general solution */
 193          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 194          for (j = zoomed.start; j < zoomed.end; j++) {
 195             i = (GLint) ((j + skipCol) * xscale);
 196             if (i < 0)
 197                i = span->end + i - 1;
 198             zoomed.color.index[j] = indexes[i];
 199          }
 200       }
 201    }
 202
 203    /* write the span in rows [r0, r1) */
 204    if (format == GL_RGBA || format == GL_RGB) {
 205       /* Writing the span may modify the colors, so make a backup now if we're
 206        * going to call _mesa_write_zoomed_span() more than once.
 207        */
 208       if (r1 - r0 > 1) {
 209          MEMCPY(rgbaSave, zoomed.color.rgba, zoomed.end * 4 * sizeof(GLchan));
 210       }
 211       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 212          _mesa_write_rgba_span(ctx, &zoomed);
 213          if (r1 - r0 > 1) {
 214             /* restore the colors */
 215             MEMCPY(zoomed.color.rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
 216          }
 217       }
 218    }
 219    else if (format == GL_COLOR_INDEX) {
 220       if (r1 - r0 > 1) {
 221          MEMCPY(indexSave, zoomed.color.index, zoomed.end * sizeof(GLuint));
 222       }
 223       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 224          _mesa_write_index_span(ctx, &zoomed);
 225          if (r1 - r0 > 1) {
 226             /* restore the colors */
 227             MEMCPY(zoomed.color.index, indexSave, zoomed.end * sizeof(GLuint));
 228          }
 229       }
 230    }
 231 }
 232
 233
 234 void
 235 _mesa_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
 236                               CONST GLchan rgba[][4], GLint y0 )
 237 {
 238    zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA);
 239 }
 240
 241
 242 void
 243 _mesa_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
 244                              CONST GLchan rgb[][3], GLint y0 )
 245 {
 246    zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB);
 247 }
 248
 249
 250 void
 251 _mesa_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
 252                                GLint y0 )
 253 {
 254   zoom_span(ctx, span, (const GLvoid *) span->color.index, y0, GL_COLOR_INDEX);
 255 }
 256
 257
 258 /*
 259  * As above, but write stencil values.
 260  */
 261 void
 262 _mesa_write_zoomed_stencil_span( GLcontext *ctx,
 263                                  GLuint n, GLint x, GLint y,
 264                                  const GLstencil stencil[], GLint y0 )
 265 {
 266    GLint m;
 267    GLint r0, r1, row, r;
 268    GLint i, j, skipcol;
 269    GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
 270    GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
 271
 272    /* compute width of output row */
 273    m = (GLint) ABSF( n * ctx->Pixel.ZoomX );
 274    if (m==0) {
 275       return;
 276    }
 277    if (ctx->Pixel.ZoomX<0.0) {
 278       /* adjust x coordinate for left/right mirroring */
 279       x = x - m;
 280    }
 281
 282    /* compute which rows to draw */
 283    row = y-y0;
 284    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 285    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 286    if (r0==r1) {
 287       return;
 288    }
 289    else if (r1<r0) {
 290       GLint rtmp = r1;
 291       r1 = r0;
 292       r0 = rtmp;
 293    }
 294
 295    /* return early if r0...r1 is above or below window */
 296    if (r0<0 && r1<0) {
 297       /* below window */
 298       return;
 299    }
 300    if (r0>=ctx->DrawBuffer->Height && r1>=ctx->DrawBuffer->Height) {
 301       /* above window */
 302       return;
 303    }
 304
 305    /* check if left edge is outside window */
 306    skipcol = 0;
 307    if (x<0) {
 308       skipcol = -x;
 309       m += x;
 310    }
 311    /* make sure span isn't too long or short */
 312    if (m>maxwidth) {
 313       m = maxwidth;
 314    }
 315    else if (m<=0) {
 316       return;
 317    }
 318
 319    ASSERT( m <= MAX_WIDTH );
 320
 321    /* zoom the span horizontally */
 322    if (ctx->Pixel.ZoomX==-1.0F) {
 323       /* n==m */
 324       for (j=0;j<m;j++) {
 325          i = n - (j+skipcol) - 1;
 326          zstencil[j] = stencil[i];
 327       }
 328    }
 329    else {
 330       GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 331       for (j=0;j<m;j++) {
 332          i = (GLint) ((j+skipcol) * xscale);
 333          if (i<0)  i = n + i - 1;
 334          zstencil[j] = stencil[i];
 335       }
 336    }
 337
 338    /* write the span */
 339    for (r=r0; r<r1; r++) {
 340       _mesa_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
 341    }
 342 }