src/mesa/swrast/s_zoom.c

   1 /* $Id: s_zoom.c,v 1.18 2002/10/24 23:57:24 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 "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 )
  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    if (format == GL_RGBA || format == GL_RGB) {
  65       zoomed.z = span->z;
  66       zoomed.zStep = span->z;
  67       zoomed.fog = span->fog;
  68       zoomed.fogStep = span->fogStep;
  69       zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
  70       zoomed.arrayMask |= SPAN_RGBA;
  71    }
  72    else if (format == GL_COLOR_INDEX) {
  73       zoomed.z = span->z;
  74       zoomed.zStep = span->z;
  75       zoomed.fog = span->fog;
  76       zoomed.fogStep = span->fogStep;
  77       zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
  78       zoomed.arrayMask |= SPAN_INDEX;
  79    }
  80
  81    /*
  82     * Compute which columns to draw: [c0, c1)
  83     */
  84    c0 = (GLint) span->x;
  85    c1 = (GLint) (span->x + span->end * ctx->Pixel.ZoomX);
  86    if (c0 == c1) {
  87       return;
  88    }
  89    else if (c1 < c0) {
  90       /* swap */
  91       GLint ctmp = c1;
  92       c1 = c0;
  93       c0 = ctmp;
  94    }
  95    if (c0 < 0) {
  96       zoomed.x = 0;
  97       zoomed.start = 0;
  98       zoomed.end = c1;
  99       skipCol = -c0;
 100    }
 101    else {
 102       zoomed.x = c0;
 103       zoomed.start = 0;
 104       zoomed.end = c1 - c0;
 105       skipCol = 0;
 106    }
 107    if (zoomed.end > maxWidth)
 108       zoomed.end = maxWidth;
 109
 110    /*
 111     * Compute which rows to draw: [r0, r1)
 112     */
 113    row = span->y - y0;
 114    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 115    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 116    if (r0 == r1) {
 117       return;
 118    }
 119    else if (r1 < r0) {
 120       /* swap */
 121       GLint rtmp = r1;
 122       r1 = r0;
 123       r0 = rtmp;
 124    }
 125
 126    ASSERT(r0 < r1);
 127    ASSERT(c0 < c1);
 128
 129    /*
 130     * Trivial clip rejection testing.
 131     */
 132    if (r1 < 0) /* below window */
 133       return;
 134    if (r0 >= (GLint) ctx->DrawBuffer->Height) /* above window */
 135       return;
 136    if (c1 < 0) /* left of window */
 137       return;
 138    if (c0 >= (GLint) ctx->DrawBuffer->Width) /* right of window */
 139       return;
 140
 141    /* zoom the span horizontally */
 142    if (format == GL_RGBA) {
 143       if (ctx->Pixel.ZoomX == -1.0F) {
 144          /* common case */
 145          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 146             i = span->end - (j + skipCol) - 1;
 147             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 148          }
 149       }
 150       else {
 151          /* general solution */
 152          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 153          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 154             i = (GLint) ((j + skipCol) * xscale);
 155             if (i < 0)
 156                i = span->end + i - 1;
 157             COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
 158          }
 159       }
 160    }
 161    else if (format == GL_RGB) {
 162       if (ctx->Pixel.ZoomX == -1.0F) {
 163          /* common case */
 164          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 165             i = span->end - (j + skipCol) - 1;
 166             zoomed.array->rgba[j][0] = rgb[i][0];
 167             zoomed.array->rgba[j][1] = rgb[i][1];
 168             zoomed.array->rgba[j][2] = rgb[i][2];
 169             zoomed.array->rgba[j][3] = CHAN_MAX;
 170          }
 171       }
 172       else {
 173          /* general solution */
 174          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 175          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 176             i = (GLint) ((j + skipCol) * xscale);
 177             if (i < 0)
 178                i = span->end + i - 1;
 179             zoomed.array->rgba[j][0] = rgb[i][0];
 180             zoomed.array->rgba[j][1] = rgb[i][1];
 181             zoomed.array->rgba[j][2] = rgb[i][2];
 182             zoomed.array->rgba[j][3] = CHAN_MAX;
 183          }
 184       }
 185    }
 186    else if (format == GL_COLOR_INDEX) {
 187       if (ctx->Pixel.ZoomX == -1.0F) {
 188          /* common case */
 189          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 190             i = span->end - (j + skipCol) - 1;
 191             zoomed.array->index[j] = indexes[i];
 192          }
 193       }
 194       else {
 195          /* general solution */
 196          const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 197          for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
 198             i = (GLint) ((j + skipCol) * xscale);
 199             if (i < 0)
 200                i = span->end + i - 1;
 201             zoomed.array->index[j] = indexes[i];
 202          }
 203       }
 204    }
 205
 206    /* write the span in rows [r0, r1) */
 207    if (format == GL_RGBA || format == GL_RGB) {
 208       /* Writing the span may modify the colors, so make a backup now if we're
 209        * going to call _mesa_write_zoomed_span() more than once.
 210        */
 211       if (r1 - r0 > 1) {
 212          MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * 4 * sizeof(GLchan));
 213       }
 214       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 215          _mesa_write_rgba_span(ctx, &zoomed);
 216          if (r1 - r0 > 1) {
 217             /* restore the colors */
 218             MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
 219          }
 220       }
 221    }
 222    else if (format == GL_COLOR_INDEX) {
 223       if (r1 - r0 > 1) {
 224          MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
 225       }
 226       for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
 227          _mesa_write_index_span(ctx, &zoomed);
 228          if (r1 - r0 > 1) {
 229             /* restore the colors */
 230             MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
 231          }
 232       }
 233    }
 234 }
 235
 236
 237 void
 238 _mesa_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
 239                               CONST GLchan rgba[][4], GLint y0 )
 240 {
 241    zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA);
 242 }
 243
 244
 245 void
 246 _mesa_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
 247                              CONST GLchan rgb[][3], GLint y0 )
 248 {
 249    zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB);
 250 }
 251
 252
 253 void
 254 _mesa_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
 255                                GLint y0 )
 256 {
 257   zoom_span(ctx, span, (const GLvoid *) span->array->index, y0, GL_COLOR_INDEX);
 258 }
 259
 260
 261 /*
 262  * As above, but write stencil values.
 263  */
 264 void
 265 _mesa_write_zoomed_stencil_span( GLcontext *ctx,
 266                                  GLuint n, GLint x, GLint y,
 267                                  const GLstencil stencil[], GLint y0 )
 268 {
 269    GLint m;
 270    GLint r0, r1, row, r;
 271    GLint i, j, skipcol;
 272    GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
 273    GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
 274
 275    /* compute width of output row */
 276    m = (GLint) ABSF( n * ctx->Pixel.ZoomX );
 277    if (m==0) {
 278       return;
 279    }
 280    if (ctx->Pixel.ZoomX<0.0) {
 281       /* adjust x coordinate for left/right mirroring */
 282       x = x - m;
 283    }
 284
 285    /* compute which rows to draw */
 286    row = y-y0;
 287    r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
 288    r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
 289    if (r0==r1) {
 290       return;
 291    }
 292    else if (r1<r0) {
 293       GLint rtmp = r1;
 294       r1 = r0;
 295       r0 = rtmp;
 296    }
 297
 298    /* return early if r0...r1 is above or below window */
 299    if (r0<0 && r1<0) {
 300       /* below window */
 301       return;
 302    }
 303    if (r0 >= (GLint) ctx->DrawBuffer->Height &&
 304        r1 >= (GLint) ctx->DrawBuffer->Height) {
 305       /* above window */
 306       return;
 307    }
 308
 309    /* check if left edge is outside window */
 310    skipcol = 0;
 311    if (x<0) {
 312       skipcol = -x;
 313       m += x;
 314    }
 315    /* make sure span isn't too long or short */
 316    if (m>maxwidth) {
 317       m = maxwidth;
 318    }
 319    else if (m<=0) {
 320       return;
 321    }
 322
 323    ASSERT( m <= MAX_WIDTH );
 324
 325    /* zoom the span horizontally */
 326    if (ctx->Pixel.ZoomX==-1.0F) {
 327       /* n==m */
 328       for (j=0;j<m;j++) {
 329          i = n - (j+skipcol) - 1;
 330          zstencil[j] = stencil[i];
 331       }
 332    }
 333    else {
 334       GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
 335       for (j=0;j<m;j++) {
 336          i = (GLint) ((j+skipcol) * xscale);
 337          if (i<0)  i = n + i - 1;
 338          zstencil[j] = stencil[i];
 339       }
 340    }
 341
 342    /* write the span */
 343    for (r=r0; r<r1; r++) {
 344       _mesa_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
 345    }
 346 }