src/mesa/drivers/x11/xm_line.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /*
  27  * This file contains "accelerated" point, line, and triangle functions.
  28  * It should be fairly easy to write new special-purpose point, line or
  29  * triangle functions and hook them into this module.
  30  */
  31
  32
  33 #include "glxheader.h"
  34 #include "main/macros.h"
  35 #include "main/mtypes.h"
  36 #include "xmesaP.h"
  37
  38 /* Internal swrast includes:
  39  */
  40 #include "swrast/s_depth.h"
  41 #include "swrast/s_points.h"
  42 #include "swrast/s_lines.h"
  43 #include "swrast/s_context.h"
  44
  45
  46 /**********************************************************************/
  47 /***                    Point rendering                             ***/
  48 /**********************************************************************/
  49
  50
  51 /*
  52  * Render an array of points into a pixmap, any pixel format.
  53  */
  54 #if 000
  55 /* XXX don't use this, it doesn't dither correctly */
  56 static void draw_points_ANY_pixmap( struct gl_context *ctx, const SWvertex *vert )
  57 {
  58    XMesaContext xmesa = XMESA_CONTEXT(ctx);
  59    XMesaDisplay *dpy = xmesa->xm_visual->display;
  60    XMesaDrawable buffer = xmesa->xm_buffer->buffer;
  61    XMesaGC gc = xmesa->xm_buffer->gc;
  62
  63    if (xmesa->xm_visual->mesa_visual.RGBAflag) {
  64       register int x, y;
  65       const GLubyte *color = vert->color;
  66       unsigned long pixel = xmesa_color_to_pixel( xmesa,
  67                                                   color[0], color[1],
  68                                                   color[2], color[3],
  69                                                   xmesa->pixelformat);
  70       XMesaSetForeground( dpy, gc, pixel );
  71       x = (GLint) vert->win[0];
  72       y = YFLIP( xrb, (GLint) vert->win[1] );
  73       XMesaDrawPoint( dpy, buffer, gc, x, y);
  74    }
  75    else {
  76       /* Color index mode */
  77       register int x, y;
  78       XMesaSetForeground( dpy, gc, vert->index );
  79       x =                         (GLint) vert->win[0];
  80       y = YFLIP( xrb, (GLint) vert->win[1] );
  81       XMesaDrawPoint( dpy, buffer, gc, x, y);
  82    }
  83 }
  84 #endif
  85
  86
  87 /* Override the swrast point-selection function.  Try to use one of
  88  * our internal point functions, otherwise fall back to the standard
  89  * swrast functions.
  90  */
  91 void xmesa_choose_point( struct gl_context *ctx )
  92 {
  93 #if 0
  94    XMesaContext xmesa = XMESA_CONTEXT(ctx);
  95    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  96
  97    if (ctx->RenderMode == GL_RENDER
  98        && ctx->Point.Size == 1.0F && !ctx->Point.SmoothFlag
  99        && swrast->_RasterMask == 0
 100        && ctx->Texture._MaxEnabledTexImageUnit == -1
 101        && xmesa->xm_buffer->buffer != XIMAGE) {
 102       swrast->Point = draw_points_ANY_pixmap;
 103    }
 104    else {
 105       _swrast_choose_point( ctx );
 106    }
 107 #else
 108    _swrast_choose_point( ctx );
 109 #endif
 110 }
 111
 112
 113
 114 /**********************************************************************/
 115 /***                      Line rendering                            ***/
 116 /**********************************************************************/
 117
 118
 119 #if CHAN_BITS == 8
 120
 121
 122 #define GET_XRB(XRB)  struct xmesa_renderbuffer *XRB = \
 123    xmesa_renderbuffer(ctx->DrawBuffer->_ColorDrawBuffers[0])
 124
 125
 126 /*
 127  * Draw a flat-shaded, PF_TRUECOLOR line into an XImage.
 128  */
 129 #define NAME flat_TRUECOLOR_line
 130 #define SETUP_CODE                                      \
 131    XMesaContext xmesa = XMESA_CONTEXT(ctx);             \
 132    GET_XRB(xrb);                                        \
 133    const GLubyte *color = vert1->color;                 \
 134    unsigned long pixel;                                 \
 135    PACK_TRUECOLOR( pixel, color[0], color[1], color[2] );
 136 #define CLIP_HACK 1
 137 #define PLOT(X,Y) XMesaPutPixel(xrb->ximage, X, YFLIP(xrb, Y), pixel );
 138 #include "swrast/s_linetemp.h"
 139
 140
 141
 142 /*
 143  * Draw a flat-shaded, PF_8A8B8G8R line into an XImage.
 144  */
 145 #define NAME flat_8A8B8G8R_line
 146 #define SETUP_CODE                                              \
 147    GET_XRB(xrb);                                                \
 148    const GLubyte *color = vert1->color;                         \
 149    GLuint pixel = PACK_8A8B8G8R(color[0], color[1], color[2], color[3]);
 150 #define PIXEL_TYPE GLuint
 151 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 152 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
 153 #define CLIP_HACK 1
 154 #define PLOT(X,Y) *pixelPtr = pixel;
 155 #include "swrast/s_linetemp.h"
 156
 157
 158
 159 /*
 160  * Draw a flat-shaded, PF_8A8R8G8B line into an XImage.
 161  */
 162 #define NAME flat_8A8R8G8B_line
 163 #define SETUP_CODE                                              \
 164    GET_XRB(xrb);                                                \
 165    const GLubyte *color = vert1->color;                         \
 166    GLuint pixel = PACK_8A8R8G8B(color[0], color[1], color[2], color[3]);
 167 #define PIXEL_TYPE GLuint
 168 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 169 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
 170 #define CLIP_HACK 1
 171 #define PLOT(X,Y) *pixelPtr = pixel;
 172 #include "swrast/s_linetemp.h"
 173
 174
 175
 176 /*
 177  * Draw a flat-shaded, PF_8R8G8B line into an XImage.
 178  */
 179 #define NAME flat_8R8G8B_line
 180 #define SETUP_CODE                                              \
 181    GET_XRB(xrb);                                                \
 182    const GLubyte *color = vert1->color;                         \
 183    GLuint pixel = PACK_8R8G8B( color[0], color[1], color[2] );
 184 #define PIXEL_TYPE GLuint
 185 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 186 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
 187 #define CLIP_HACK 1
 188 #define PLOT(X,Y) *pixelPtr = pixel;
 189 #include "swrast/s_linetemp.h"
 190
 191
 192
 193 /*
 194  * Draw a flat-shaded, PF_8R8G8B24 line into an XImage.
 195  */
 196 #define NAME flat_8R8G8B24_line
 197 #define SETUP_CODE                                              \
 198    GET_XRB(xrb);                                                \
 199    const GLubyte *color = vert1->color;
 200 #define PIXEL_TYPE bgr_t
 201 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 202 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR3(xrb, X, Y)
 203 #define CLIP_HACK 1
 204 #define PLOT(X,Y) {                     \
 205       pixelPtr->r = color[RCOMP];       \
 206       pixelPtr->g = color[GCOMP];       \
 207       pixelPtr->b = color[BCOMP];       \
 208 }
 209 #include "swrast/s_linetemp.h"
 210
 211
 212
 213 /*
 214  * Draw a flat-shaded, PF_5R6G5B line into an XImage.
 215  */
 216 #define NAME flat_5R6G5B_line
 217 #define SETUP_CODE                                              \
 218    GET_XRB(xrb);                                                \
 219    const GLubyte *color = vert1->color;                         \
 220    GLushort pixel = PACK_5R6G5B( color[0], color[1], color[2] );
 221 #define PIXEL_TYPE GLushort
 222 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 223 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X, Y)
 224 #define CLIP_HACK 1
 225 #define PLOT(X,Y) *pixelPtr = pixel;
 226 #include "swrast/s_linetemp.h"
 227
 228
 229
 230 /*
 231  * Draw a flat-shaded, PF_DITHER_5R6G5B line into an XImage.
 232  */
 233 #define NAME flat_DITHER_5R6G5B_line
 234 #define SETUP_CODE                                              \
 235    GET_XRB(xrb);                                                \
 236    XMesaContext xmesa = XMESA_CONTEXT(ctx);                     \
 237    const GLubyte *color = vert1->color;
 238 #define PIXEL_TYPE GLushort
 239 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 240 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X, Y)
 241 #define CLIP_HACK 1
 242 #define PLOT(X,Y) PACK_TRUEDITHER( *pixelPtr, X, Y, color[0], color[1], color[2] );
 243 #include "swrast/s_linetemp.h"
 244
 245
 246
 247 /*
 248  * Draw a flat-shaded, Z-less, PF_TRUECOLOR line into an XImage.
 249  */
 250 #define NAME flat_TRUECOLOR_z_line
 251 #define SETUP_CODE                                              \
 252    GET_XRB(xrb);                                                \
 253    XMesaContext xmesa = XMESA_CONTEXT(ctx);                     \
 254    const GLubyte *color = vert1->color;                         \
 255    unsigned long pixel;                                         \
 256    PACK_TRUECOLOR( pixel, color[0], color[1], color[2] );
 257 #define INTERP_Z 1
 258 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 259 #define CLIP_HACK 1
 260 #define PLOT(X,Y)                                                       \
 261         if (Z < *zPtr) {                                                \
 262            *zPtr = Z;                                                   \
 263            XMesaPutPixel(xrb->ximage, X, YFLIP(xrb, Y), pixel);         \
 264         }
 265 #include "swrast/s_linetemp.h"
 266
 267
 268
 269 /*
 270  * Draw a flat-shaded, Z-less, PF_8A8B8G8R line into an XImage.
 271  */
 272 #define NAME flat_8A8B8G8R_z_line
 273 #define SETUP_CODE                                              \
 274    GET_XRB(xrb);                                                \
 275    const GLubyte *color = vert1->color;                         \
 276    GLuint pixel = PACK_8A8B8G8R(color[0], color[1], color[2], color[3]);
 277 #define INTERP_Z 1
 278 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 279 #define PIXEL_TYPE GLuint
 280 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 281 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
 282 #define CLIP_HACK 1
 283 #define PLOT(X,Y)               \
 284         if (Z < *zPtr) {        \
 285            *zPtr = Z;           \
 286            *pixelPtr = pixel;   \
 287         }
 288 #include "swrast/s_linetemp.h"
 289
 290
 291
 292 /*
 293  * Draw a flat-shaded, Z-less, PF_8A8R8G8B line into an XImage.
 294  */
 295 #define NAME flat_8A8R8G8B_z_line
 296 #define SETUP_CODE                                              \
 297    GET_XRB(xrb);                                                \
 298    const GLubyte *color = vert1->color;                         \
 299    GLuint pixel = PACK_8A8R8G8B(color[0], color[1], color[2], color[3]);
 300 #define INTERP_Z 1
 301 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 302 #define PIXEL_TYPE GLuint
 303 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 304 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
 305 #define CLIP_HACK 1
 306 #define PLOT(X,Y)               \
 307         if (Z < *zPtr) {        \
 308            *zPtr = Z;           \
 309            *pixelPtr = pixel;   \
 310         }
 311 #include "swrast/s_linetemp.h"
 312
 313
 314
 315 /*
 316  * Draw a flat-shaded, Z-less, PF_8R8G8B line into an XImage.
 317  */
 318 #define NAME flat_8R8G8B_z_line
 319 #define SETUP_CODE                                              \
 320    GET_XRB(xrb);                                                \
 321    const GLubyte *color = vert1->color;                         \
 322    GLuint pixel = PACK_8R8G8B( color[0], color[1], color[2] );
 323 #define INTERP_Z 1
 324 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 325 #define PIXEL_TYPE GLuint
 326 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 327 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
 328 #define CLIP_HACK 1
 329 #define PLOT(X,Y)               \
 330         if (Z < *zPtr) {        \
 331            *zPtr = Z;           \
 332            *pixelPtr = pixel;   \
 333         }
 334 #include "swrast/s_linetemp.h"
 335
 336
 337
 338 /*
 339  * Draw a flat-shaded, Z-less, PF_8R8G8B24 line into an XImage.
 340  */
 341 #define NAME flat_8R8G8B24_z_line
 342 #define SETUP_CODE                                              \
 343    GET_XRB(xrb);                                                \
 344    const GLubyte *color = vert1->color;
 345 #define INTERP_Z 1
 346 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 347 #define PIXEL_TYPE bgr_t
 348 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 349 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR3(xrb, X,Y)
 350 #define CLIP_HACK 1
 351 #define PLOT(X,Y)                       \
 352         if (Z < *zPtr) {                \
 353            *zPtr = Z;                   \
 354            pixelPtr->r = color[RCOMP];  \
 355            pixelPtr->g = color[GCOMP];  \
 356            pixelPtr->b = color[BCOMP];  \
 357         }
 358 #include "swrast/s_linetemp.h"
 359
 360
 361
 362 /*
 363  * Draw a flat-shaded, Z-less, PF_5R6G5B line into an XImage.
 364  */
 365 #define NAME flat_5R6G5B_z_line
 366 #define SETUP_CODE                                              \
 367    GET_XRB(xrb);                                                \
 368    const GLubyte *color = vert1->color;                         \
 369    GLushort pixel = PACK_5R6G5B( color[0], color[1], color[2] );
 370 #define INTERP_Z 1
 371 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 372 #define PIXEL_TYPE GLushort
 373 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 374 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X,Y)
 375 #define CLIP_HACK 1
 376 #define PLOT(X,Y)               \
 377         if (Z < *zPtr) {        \
 378            *zPtr = Z;           \
 379            *pixelPtr = pixel;   \
 380         }
 381 #include "swrast/s_linetemp.h"
 382
 383
 384
 385 /*
 386  * Draw a flat-shaded, Z-less, PF_DITHER_5R6G5B line into an XImage.
 387  */
 388 #define NAME flat_DITHER_5R6G5B_z_line
 389 #define SETUP_CODE                                      \
 390    GET_XRB(xrb);                                                \
 391    XMesaContext xmesa = XMESA_CONTEXT(ctx);             \
 392    const GLubyte *color = vert1->color;
 393 #define INTERP_Z 1
 394 #define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
 395 #define PIXEL_TYPE GLushort
 396 #define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
 397 #define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X,Y)
 398 #define CLIP_HACK 1
 399 #define PLOT(X,Y)               \
 400         if (Z < *zPtr) {        \
 401            *zPtr = Z;           \
 402            PACK_TRUEDITHER(*pixelPtr, X, Y, color[0], color[1], color[2]); \
 403         }
 404 #include "swrast/s_linetemp.h"
 405
 406
 407
 408 /**
 409  * Draw fast, XOR line with XDrawLine in front color buffer.
 410  * WARNING: this isn't fully OpenGL conformant because different pixels
 411  * will be hit versus using the other line functions.
 412  * Don't use the code in X server GLcore module since we need a wrapper
 413  * for the XSetLineAttributes() function call.
 414  */
 415 static void
 416 xor_line(struct gl_context *ctx, const SWvertex *vert0, const SWvertex *vert1)
 417 {
 418    XMesaContext xmesa = XMESA_CONTEXT(ctx);
 419    XMesaDisplay *dpy = xmesa->xm_visual->display;
 420    XMesaGC gc = xmesa->xm_buffer->gc;
 421    GET_XRB(xrb);
 422    unsigned long pixel = xmesa_color_to_pixel(ctx,
 423                                               vert1->color[0], vert1->color[1],
 424                                               vert1->color[2], vert1->color[3],
 425                                               xmesa->pixelformat);
 426    int x0 =            (GLint) vert0->attrib[VARYING_SLOT_POS][0];
 427    int y0 = YFLIP(xrb, (GLint) vert0->attrib[VARYING_SLOT_POS][1]);
 428    int x1 =            (GLint) vert1->attrib[VARYING_SLOT_POS][0];
 429    int y1 = YFLIP(xrb, (GLint) vert1->attrib[VARYING_SLOT_POS][1]);
 430    XMesaSetForeground(dpy, gc, pixel);
 431    XMesaSetFunction(dpy, gc, GXxor);
 432    XSetLineAttributes(dpy, gc, (int) ctx->Line.Width,
 433                       LineSolid, CapButt, JoinMiter);
 434    XDrawLine(dpy, xrb->pixmap, gc, x0, y0, x1, y1);
 435    XMesaSetFunction(dpy, gc, GXcopy);  /* this gc is used elsewhere */
 436 }
 437
 438
 439 #endif /* CHAN_BITS == 8 */
 440
 441
 442 /**
 443  * Return pointer to line drawing function, or NULL if we should use a
 444  * swrast fallback.
 445  */
 446 static swrast_line_func
 447 get_line_func(struct gl_context *ctx)
 448 {
 449 #if CHAN_BITS == 8
 450    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 451    XMesaContext xmesa = XMESA_CONTEXT(ctx);
 452    const struct xmesa_renderbuffer *xrb;
 453
 454    if ((ctx->DrawBuffer->_ColorDrawBufferIndexes[0] != BUFFER_BIT_FRONT_LEFT) &&
 455        (ctx->DrawBuffer->_ColorDrawBufferIndexes[0] != BUFFER_BIT_BACK_LEFT))
 456       return (swrast_line_func) NULL;
 457    if (ctx->RenderMode != GL_RENDER)      return (swrast_line_func) NULL;
 458    if (ctx->Line.SmoothFlag)              return (swrast_line_func) NULL;
 459    if (ctx->Texture._MaxEnabledTexImageUnit != -1)        return (swrast_line_func) NULL;
 460    if (ctx->Light.ShadeModel != GL_FLAT)  return (swrast_line_func) NULL;
 461    if (ctx->Line.StippleFlag)             return (swrast_line_func) NULL;
 462    if (swrast->_RasterMask & MULTI_DRAW_BIT) return (swrast_line_func) NULL;
 463
 464    xrb = xmesa_renderbuffer(ctx->DrawBuffer->_ColorDrawBuffers[0]);
 465
 466    if (xrb->ximage
 467        && swrast->_RasterMask==DEPTH_BIT
 468        && ctx->Depth.Func==GL_LESS
 469        && ctx->Depth.Mask==GL_TRUE
 470        && ctx->Visual.depthBits == DEFAULT_SOFTWARE_DEPTH_BITS
 471        && ctx->Line.Width==1.0F) {
 472       switch (xmesa->pixelformat) {
 473          case PF_Truecolor:
 474             return flat_TRUECOLOR_z_line;
 475          case PF_8A8B8G8R:
 476             return flat_8A8B8G8R_z_line;
 477          case PF_8A8R8G8B:
 478             return flat_8A8R8G8B_z_line;
 479          case PF_8R8G8B:
 480             return flat_8R8G8B_z_line;
 481          case PF_8R8G8B24:
 482             return flat_8R8G8B24_z_line;
 483          case PF_5R6G5B:
 484             return flat_5R6G5B_z_line;
 485          case PF_Dither_5R6G5B:
 486             return flat_DITHER_5R6G5B_z_line;
 487          default:
 488             return (swrast_line_func)NULL;
 489       }
 490    }
 491    if (xrb->ximage
 492        && swrast->_RasterMask==0
 493        && ctx->Line.Width==1.0F) {
 494       switch (xmesa->pixelformat) {
 495          case PF_Truecolor:
 496             return flat_TRUECOLOR_line;
 497          case PF_8A8B8G8R:
 498             return flat_8A8B8G8R_line;
 499          case PF_8A8R8G8B:
 500             return flat_8A8R8G8B_line;
 501          case PF_8R8G8B:
 502             return flat_8R8G8B_line;
 503          case PF_8R8G8B24:
 504             return flat_8R8G8B24_line;
 505          case PF_5R6G5B:
 506             return flat_5R6G5B_line;
 507          case PF_Dither_5R6G5B:
 508             return flat_DITHER_5R6G5B_line;
 509          default:
 510             return (swrast_line_func)NULL;
 511       }
 512    }
 513
 514    if (ctx->DrawBuffer->_NumColorDrawBuffers == 1
 515        && ctx->DrawBuffer->_ColorDrawBufferIndexes[0] == BUFFER_FRONT_LEFT
 516        && swrast->_RasterMask == LOGIC_OP_BIT
 517        && ctx->Color.LogicOp == GL_XOR
 518        && !ctx->Line.StippleFlag
 519        && !ctx->Line.SmoothFlag) {
 520       return xor_line;
 521    }
 522
 523 #endif /* CHAN_BITS == 8 */
 524    return (swrast_line_func) NULL;
 525 }
 526
 527
 528 /**
 529  * Override for the swrast line-selection function.  Try to use one
 530  * of our internal line functions, otherwise fall back to the
 531  * standard swrast functions.
 532  */
 533 void
 534 xmesa_choose_line(struct gl_context *ctx)
 535 {
 536    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 537
 538    if (!(swrast->Line = get_line_func( ctx )))
 539       _swrast_choose_line( ctx );
 540 }