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path: root/src/mesa/drivers/x11/xm_line.c
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/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/*
 * This file contains "accelerated" point, line, and triangle functions.
 * It should be fairly easy to write new special-purpose point, line or
 * triangle functions and hook them into this module.
 */


#include "glxheader.h"
#include "main/depth.h"
#include "main/macros.h"
#include "main/mtypes.h"
#include "xmesaP.h"

/* Internal swrast includes:
 */
#include "swrast/s_depth.h"
#include "swrast/s_points.h"
#include "swrast/s_lines.h"
#include "swrast/s_context.h"


/**********************************************************************/
/***                    Point rendering                             ***/
/**********************************************************************/


/*
 * Render an array of points into a pixmap, any pixel format.
 */
#if 000
/* XXX don't use this, it doesn't dither correctly */
static void draw_points_ANY_pixmap( struct gl_context *ctx, const SWvertex *vert )
{
   XMesaContext xmesa = XMESA_CONTEXT(ctx);
   XMesaDisplay *dpy = xmesa->xm_visual->display;
   XMesaDrawable buffer = xmesa->xm_buffer->buffer;
   XMesaGC gc = xmesa->xm_buffer->gc;

   if (xmesa->xm_visual->mesa_visual.RGBAflag) {
      register int x, y;
      const GLubyte *color = vert->color;
      unsigned long pixel = xmesa_color_to_pixel( xmesa,
						  color[0], color[1],
						  color[2], color[3],
						  xmesa->pixelformat);
      XMesaSetForeground( dpy, gc, pixel );
      x = (GLint) vert->win[0];
      y = YFLIP( xrb, (GLint) vert->win[1] );
      XMesaDrawPoint( dpy, buffer, gc, x, y);
   }
   else {
      /* Color index mode */
      register int x, y;
      XMesaSetForeground( dpy, gc, vert->index );
      x =                         (GLint) vert->win[0];
      y = YFLIP( xrb, (GLint) vert->win[1] );
      XMesaDrawPoint( dpy, buffer, gc, x, y);
   }
}
#endif


/* Override the swrast point-selection function.  Try to use one of
 * our internal point functions, otherwise fall back to the standard
 * swrast functions.
 */
void xmesa_choose_point( struct gl_context *ctx )
{
#if 0
   XMesaContext xmesa = XMESA_CONTEXT(ctx);
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   if (ctx->RenderMode == GL_RENDER
       && ctx->Point.Size == 1.0F && !ctx->Point.SmoothFlag
       && swrast->_RasterMask == 0
       && !ctx->Texture._EnabledUnits
       && xmesa->xm_buffer->buffer != XIMAGE) {
      swrast->Point = draw_points_ANY_pixmap;
   }
   else {
      _swrast_choose_point( ctx );
   }
#else
   _swrast_choose_point( ctx );
#endif
}



/**********************************************************************/
/***                      Line rendering                            ***/
/**********************************************************************/


#if CHAN_BITS == 8


#define GET_XRB(XRB)  struct xmesa_renderbuffer *XRB = \
   xmesa_renderbuffer(ctx->DrawBuffer->_ColorDrawBuffers[0]->Wrapped)


/*
 * Draw a flat-shaded, PF_TRUECOLOR line into an XImage.
 */
#define NAME flat_TRUECOLOR_line
#define SETUP_CODE					\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);		\
   GET_XRB(xrb);					\
   const GLubyte *color = vert1->color;			\
   unsigned long pixel;					\
   PACK_TRUECOLOR( pixel, color[0], color[1], color[2] );
#define CLIP_HACK 1
#define PLOT(X,Y) XMesaPutPixel(xrb->ximage, X, YFLIP(xrb, Y), pixel );
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_8A8B8G8R line into an XImage.
 */
#define NAME flat_8A8B8G8R_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8A8B8G8R(color[0], color[1], color[2], color[3]);
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = pixel;
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_8A8R8G8B line into an XImage.
 */
#define NAME flat_8A8R8G8B_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8A8R8G8B(color[0], color[1], color[2], color[3]);
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = pixel;
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_8R8G8B line into an XImage.
 */
#define NAME flat_8R8G8B_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8R8G8B( color[0], color[1], color[2] );
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = pixel;
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_8R8G8B24 line into an XImage.
 */
#define NAME flat_8R8G8B24_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;
#define PIXEL_TYPE bgr_t
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR3(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) {			\
      pixelPtr->r = color[RCOMP];	\
      pixelPtr->g = color[GCOMP];	\
      pixelPtr->b = color[BCOMP];	\
}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_5R6G5B line into an XImage.
 */
#define NAME flat_5R6G5B_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLushort pixel = PACK_5R6G5B( color[0], color[1], color[2] );
#define PIXEL_TYPE GLushort
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = pixel;
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_DITHER_5R6G5B line into an XImage.
 */
#define NAME flat_DITHER_5R6G5B_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);			\
   const GLubyte *color = vert1->color;
#define PIXEL_TYPE GLushort
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) PACK_TRUEDITHER( *pixelPtr, X, Y, color[0], color[1], color[2] );
#include "swrast/s_linetemp.h"




/*
 * Draw a flat-shaded, PF_DITHER 8-bit line into an XImage.
 */
#define NAME flat_DITHER8_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLint r = color[0], g = color[1], b = color[2];		\
   DITHER_SETUP;
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X, Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = DITHER(X,Y,r,g,b);
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_LOOKUP 8-bit line into an XImage.
 */
#define NAME flat_LOOKUP8_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLubyte pixel;						\
   LOOKUP_SETUP;						\
   pixel = (GLubyte) LOOKUP( color[0], color[1], color[2] );
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = pixel;
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, PF_HPCR line into an XImage.
 */
#define NAME flat_HPCR_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);			\
   const GLubyte *color = vert1->color;				\
   GLint r = color[0], g = color[1], b = color[2];
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y) *pixelPtr = (GLubyte) DITHER_HPCR(X,Y,r,g,b);
#include "swrast/s_linetemp.h"




/*
 * Draw a flat-shaded, Z-less, PF_TRUECOLOR line into an XImage.
 */
#define NAME flat_TRUECOLOR_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);			\
   const GLubyte *color = vert1->color;				\
   unsigned long pixel;						\
   PACK_TRUECOLOR( pixel, color[0], color[1], color[2] );
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define CLIP_HACK 1
#define PLOT(X,Y)							\
	if (Z < *zPtr) {						\
	   *zPtr = Z;							\
           XMesaPutPixel(xrb->ximage, X, YFLIP(xrb, Y), pixel);		\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_8A8B8G8R line into an XImage.
 */
#define NAME flat_8A8B8G8R_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8A8B8G8R(color[0], color[1], color[2], color[3]);
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   *pixelPtr = pixel;	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_8A8R8G8B line into an XImage.
 */
#define NAME flat_8A8R8G8B_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8A8R8G8B(color[0], color[1], color[2], color[3]);
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   *pixelPtr = pixel;	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_8R8G8B line into an XImage.
 */
#define NAME flat_8R8G8B_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLuint pixel = PACK_8R8G8B( color[0], color[1], color[2] );
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLuint
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR4(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   *pixelPtr = pixel;	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_8R8G8B24 line into an XImage.
 */
#define NAME flat_8R8G8B24_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE bgr_t
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR3(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)			\
	if (Z < *zPtr) {		\
	   *zPtr = Z;			\
           pixelPtr->r = color[RCOMP];	\
           pixelPtr->g = color[GCOMP];	\
           pixelPtr->b = color[BCOMP];	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_5R6G5B line into an XImage.
 */
#define NAME flat_5R6G5B_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLushort pixel = PACK_5R6G5B( color[0], color[1], color[2] );
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLushort
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   *pixelPtr = pixel;	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_DITHER_5R6G5B line into an XImage.
 */
#define NAME flat_DITHER_5R6G5B_z_line
#define SETUP_CODE					\
   GET_XRB(xrb);						\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);		\
   const GLubyte *color = vert1->color;
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLushort
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR2(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   PACK_TRUEDITHER(*pixelPtr, X, Y, color[0], color[1], color[2]); \
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_DITHER 8-bit line into an XImage.
 */
#define NAME flat_DITHER8_z_line
#define SETUP_CODE					\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;			\
   GLint r = color[0], g = color[1], b = color[2];	\
   DITHER_SETUP;
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)						\
	if (Z < *zPtr) {					\
	   *zPtr = Z;						\
	   *pixelPtr = (GLubyte) DITHER( X, Y, r, g, b);	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_LOOKUP 8-bit line into an XImage.
 */
#define NAME flat_LOOKUP8_z_line
#define SETUP_CODE						\
   GET_XRB(xrb);						\
   const GLubyte *color = vert1->color;				\
   GLubyte pixel;						\
   LOOKUP_SETUP;						\
   pixel = (GLubyte) LOOKUP( color[0], color[1], color[2] );
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)		\
	if (Z < *zPtr) {	\
	   *zPtr = Z;		\
	   *pixelPtr = pixel;	\
	}
#include "swrast/s_linetemp.h"



/*
 * Draw a flat-shaded, Z-less, PF_HPCR line into an XImage.
 */
#define NAME flat_HPCR_z_line
#define SETUP_CODE 						\
   GET_XRB(xrb);						\
   XMesaContext xmesa = XMESA_CONTEXT(ctx);			\
   const GLubyte *color = vert1->color;				\
   GLint r = color[0], g = color[1], b = color[2];
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define PIXEL_TYPE GLubyte
#define BYTES_PER_ROW (xrb->ximage->bytes_per_line)
#define PIXEL_ADDRESS(X,Y) PIXEL_ADDR1(xrb, X,Y)
#define CLIP_HACK 1
#define PLOT(X,Y)						\
	if (Z < *zPtr) {					\
	   *zPtr = Z;						\
	   *pixelPtr = (GLubyte) DITHER_HPCR( X, Y, r, g, b);	\
	}
#include "swrast/s_linetemp.h"




#ifndef XFree86Server
/**
 * Draw fast, XOR line with XDrawLine in front color buffer.
 * WARNING: this isn't fully OpenGL conformant because different pixels
 * will be hit versus using the other line functions.
 * Don't use the code in X server GLcore module since we need a wrapper
 * for the XSetLineAttributes() function call.
 */
static void
xor_line(struct gl_context *ctx, const SWvertex *vert0, const SWvertex *vert1)
{
   XMesaContext xmesa = XMESA_CONTEXT(ctx);
   XMesaDisplay *dpy = xmesa->xm_visual->display;
   XMesaGC gc = xmesa->xm_buffer->gc;
   GET_XRB(xrb);
   unsigned long pixel = xmesa_color_to_pixel(ctx,
                                              vert1->color[0], vert1->color[1],
                                              vert1->color[2], vert1->color[3],
                                              xmesa->pixelformat);
   int x0 =            (GLint) vert0->attrib[FRAG_ATTRIB_WPOS][0];
   int y0 = YFLIP(xrb, (GLint) vert0->attrib[FRAG_ATTRIB_WPOS][1]);
   int x1 =            (GLint) vert1->attrib[FRAG_ATTRIB_WPOS][0];
   int y1 = YFLIP(xrb, (GLint) vert1->attrib[FRAG_ATTRIB_WPOS][1]);
   XMesaSetForeground(dpy, gc, pixel);
   XMesaSetFunction(dpy, gc, GXxor);
   XSetLineAttributes(dpy, gc, (int) ctx->Line.Width,
                      LineSolid, CapButt, JoinMiter);
   XDrawLine(dpy, xrb->pixmap, gc, x0, y0, x1, y1);
   XMesaSetFunction(dpy, gc, GXcopy);  /* this gc is used elsewhere */
}
#endif /* XFree86Server */


#endif /* CHAN_BITS == 8 */


/**
 * Return pointer to line drawing function, or NULL if we should use a
 * swrast fallback.
 */
static swrast_line_func
get_line_func(struct gl_context *ctx)
{
#if CHAN_BITS == 8
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   XMesaContext xmesa = XMESA_CONTEXT(ctx);
   XMesaBuffer xmbuf = XMESA_BUFFER(ctx->DrawBuffer);
   const int depth = GET_VISUAL_DEPTH(xmesa->xm_visual);
   const struct xmesa_renderbuffer *xrb;

   if ((ctx->DrawBuffer->_ColorDrawBufferIndexes[0] != BUFFER_BIT_FRONT_LEFT) &&
       (ctx->DrawBuffer->_ColorDrawBufferIndexes[0] != BUFFER_BIT_BACK_LEFT))
      return (swrast_line_func) NULL;
   if (ctx->RenderMode != GL_RENDER)      return (swrast_line_func) NULL;
   if (ctx->Line.SmoothFlag)              return (swrast_line_func) NULL;
   if (ctx->Texture._EnabledUnits)        return (swrast_line_func) NULL;
   if (ctx->Light.ShadeModel != GL_FLAT)  return (swrast_line_func) NULL;
   if (ctx->Line.StippleFlag)             return (swrast_line_func) NULL;
   if (swrast->_RasterMask & MULTI_DRAW_BIT) return (swrast_line_func) NULL;
   if (xmbuf->swAlpha)                    return (swrast_line_func) NULL;

   xrb = xmesa_renderbuffer(ctx->DrawBuffer->_ColorDrawBuffers[0]->Wrapped);

   if (xrb->ximage
       && swrast->_RasterMask==DEPTH_BIT
       && ctx->Depth.Func==GL_LESS
       && ctx->Depth.Mask==GL_TRUE
       && ctx->Visual.depthBits == DEFAULT_SOFTWARE_DEPTH_BITS
       && ctx->Line.Width==1.0F) {
      switch (xmesa->pixelformat) {
         case PF_Truecolor:
            return flat_TRUECOLOR_z_line;
         case PF_8A8B8G8R:
            return flat_8A8B8G8R_z_line;
         case PF_8A8R8G8B:
            return flat_8A8R8G8B_z_line;
         case PF_8R8G8B:
            return flat_8R8G8B_z_line;
         case PF_8R8G8B24:
            return flat_8R8G8B24_z_line;
         case PF_5R6G5B:
            return flat_5R6G5B_z_line;
         case PF_Dither_5R6G5B:
            return flat_DITHER_5R6G5B_z_line;
         case PF_Dither:
            return (depth==8) ? flat_DITHER8_z_line : (swrast_line_func) NULL;
         case PF_Lookup:
            return (depth==8) ? flat_LOOKUP8_z_line : (swrast_line_func) NULL;
         case PF_HPCR:
            return flat_HPCR_z_line;
         default:
            return (swrast_line_func)NULL;
      }
   }
   if (xrb->ximage
       && swrast->_RasterMask==0
       && ctx->Line.Width==1.0F) {
      switch (xmesa->pixelformat) {
         case PF_Truecolor:
            return flat_TRUECOLOR_line;
         case PF_8A8B8G8R:
            return flat_8A8B8G8R_line;
         case PF_8A8R8G8B:
            return flat_8A8R8G8B_line;
         case PF_8R8G8B:
            return flat_8R8G8B_line;
         case PF_8R8G8B24:
            return flat_8R8G8B24_line;
         case PF_5R6G5B:
            return flat_5R6G5B_line;
         case PF_Dither_5R6G5B:
            return flat_DITHER_5R6G5B_line;
         case PF_Dither:
            return (depth==8) ? flat_DITHER8_line : (swrast_line_func) NULL;
         case PF_Lookup:
            return (depth==8) ? flat_LOOKUP8_line : (swrast_line_func) NULL;
         case PF_HPCR:
            return flat_HPCR_line;
	 default:
	    return (swrast_line_func)NULL;
      }
   }

#ifndef XFree86Server
   if (ctx->DrawBuffer->_NumColorDrawBuffers == 1
       && ctx->DrawBuffer->_ColorDrawBufferIndexes[0] == BUFFER_FRONT_LEFT
       && swrast->_RasterMask == LOGIC_OP_BIT
       && ctx->Color.LogicOp == GL_XOR
       && !ctx->Line.StippleFlag
       && !ctx->Line.SmoothFlag) {
      return xor_line;
   }
#endif /* XFree86Server */

#endif /* CHAN_BITS == 8 */
   return (swrast_line_func) NULL;
}


/**
 * Override for the swrast line-selection function.  Try to use one
 * of our internal line functions, otherwise fall back to the
 * standard swrast functions.
 */
void
xmesa_choose_line(struct gl_context *ctx)
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   if (!(swrast->Line = get_line_func( ctx )))
      _swrast_choose_line( ctx );
}