예제 #1
0
static void merge_edgeflags( struct brw_clip_compile *c )
{
   struct brw_compile *p = &c->func;
   struct brw_reg tmp0 = get_element_ud(c->reg.tmp0, 0);

   brw_AND(p, tmp0, get_element_ud(c->reg.R0, 2), brw_imm_ud(PRIM_MASK)); 
   brw_CMP(p, 
	   vec1(brw_null_reg()), 
	   BRW_CONDITIONAL_EQ, 
	   tmp0,
	   brw_imm_ud(_3DPRIM_POLYGON));

   /* Get away with using reg.vertex because we know that this is not
    * a _3DPRIM_TRISTRIP_REVERSE:
    */
   brw_IF(p, BRW_EXECUTE_1);
   {   
      brw_set_conditionalmod(p, BRW_CONDITIONAL_EQ);
      brw_AND(p, vec1(brw_null_reg()), get_element_ud(c->reg.R0, 2), brw_imm_ud(1<<8));
      brw_MOV(p, byte_offset(c->reg.vertex[0],
                             brw_vert_result_to_offset(&c->vue_map,
                                                       VARYING_SLOT_EDGE)),
              brw_imm_f(0));
      brw_set_predicate_control(p, BRW_PREDICATE_NONE);

      brw_set_conditionalmod(p, BRW_CONDITIONAL_EQ);
      brw_AND(p, vec1(brw_null_reg()), get_element_ud(c->reg.R0, 2), brw_imm_ud(1<<9));
      brw_MOV(p, byte_offset(c->reg.vertex[2],
                             brw_vert_result_to_offset(&c->vue_map,
                                                       VARYING_SLOT_EDGE)),
              brw_imm_f(0));
      brw_set_predicate_control(p, BRW_PREDICATE_NONE);
   }
   brw_ENDIF(p);
}
예제 #2
0
static void copy_bfc( struct brw_clip_compile *c )
{
   struct brw_compile *p = &c->func;
   GLuint conditional;

   /* Do we have any colors to copy? 
    */
   if (!(brw_clip_have_vert_result(c, VARYING_SLOT_COL0) &&
         brw_clip_have_vert_result(c, VARYING_SLOT_BFC0)) &&
       !(brw_clip_have_vert_result(c, VARYING_SLOT_COL1) &&
         brw_clip_have_vert_result(c, VARYING_SLOT_BFC1)))
      return;

   /* In some wierd degnerate cases we can end up testing the
    * direction twice, once for culling and once for bfc copying.  Oh
    * well, that's what you get for setting wierd GL state.
    */
   if (c->key.copy_bfc_ccw)
      conditional = BRW_CONDITIONAL_GE;
   else
      conditional = BRW_CONDITIONAL_L;

   brw_CMP(p,
	   vec1(brw_null_reg()),
	   conditional,
	   get_element(c->reg.dir, 2),
	   brw_imm_f(0));
   
   brw_IF(p, BRW_EXECUTE_1);
   {
      GLuint i;

      for (i = 0; i < 3; i++) {
	 if (brw_clip_have_vert_result(c, VARYING_SLOT_COL0) &&
             brw_clip_have_vert_result(c, VARYING_SLOT_BFC0))
	    brw_MOV(p, 
		    byte_offset(c->reg.vertex[i],
                                brw_vert_result_to_offset(&c->vue_map,
                                                          VARYING_SLOT_COL0)),
		    byte_offset(c->reg.vertex[i],
                                brw_vert_result_to_offset(&c->vue_map,
                                                          VARYING_SLOT_BFC0)));

	 if (brw_clip_have_vert_result(c, VARYING_SLOT_COL1) &&
             brw_clip_have_vert_result(c, VARYING_SLOT_BFC1))
	    brw_MOV(p, 
		    byte_offset(c->reg.vertex[i],
                                brw_vert_result_to_offset(&c->vue_map,
                                                          VARYING_SLOT_COL1)),
		    byte_offset(c->reg.vertex[i],
                                brw_vert_result_to_offset(&c->vue_map,
                                                          VARYING_SLOT_BFC1)));
      }
   }
   brw_ENDIF(p);
}
예제 #3
0
static void apply_one_offset( struct brw_clip_compile *c,
			  struct brw_indirect vert )
{
   struct brw_compile *p = &c->func;
   GLuint ndc_offset = brw_vert_result_to_offset(&c->vue_map,
                                                 BRW_VARYING_SLOT_NDC);
   struct brw_reg z = deref_1f(vert, ndc_offset +
			       2 * type_sz(BRW_REGISTER_TYPE_F));

   brw_ADD(p, z, z, vec1(c->reg.offset));
}
예제 #4
0
/* This is performed against the original triangles, so no indirection
 * required:
BZZZT!
 */
static void compute_tri_direction( struct brw_clip_compile *c )
{
   struct brw_compile *p = &c->func;
   struct brw_reg e = c->reg.tmp0;
   struct brw_reg f = c->reg.tmp1;
   GLuint hpos_offset = brw_vert_result_to_offset(&c->vue_map,
                                                  VARYING_SLOT_POS);
   struct brw_reg v0 = byte_offset(c->reg.vertex[0], hpos_offset);
   struct brw_reg v1 = byte_offset(c->reg.vertex[1], hpos_offset);
   struct brw_reg v2 = byte_offset(c->reg.vertex[2], hpos_offset);


   struct brw_reg v0n = get_tmp(c);
   struct brw_reg v1n = get_tmp(c);
   struct brw_reg v2n = get_tmp(c);

   /* Convert to NDC.
    * NOTE: We can't modify the original vertex coordinates,
    * as it may impact further operations.
    * So, we have to keep normalized coordinates in temp registers.
    *
    * TBD-KC
    * Try to optimize unnecessary MOV's.
    */
   brw_MOV(p, v0n, v0);
   brw_MOV(p, v1n, v1);
   brw_MOV(p, v2n, v2);

   brw_clip_project_position(c, v0n);
   brw_clip_project_position(c, v1n);
   brw_clip_project_position(c, v2n);

   /* Calculate the vectors of two edges of the triangle:
    */
   brw_ADD(p, e, v0n, negate(v2n)); 
   brw_ADD(p, f, v1n, negate(v2n)); 

   /* Take their crossproduct:
    */
   brw_set_access_mode(p, BRW_ALIGN_16);
   brw_MUL(p, vec4(brw_null_reg()), brw_swizzle(e, 1,2,0,3),  brw_swizzle(f,2,0,1,3));
   brw_MAC(p, vec4(e),  negate(brw_swizzle(e, 2,0,1,3)), brw_swizzle(f,1,2,0,3));
   brw_set_access_mode(p, BRW_ALIGN_1);

   brw_MUL(p, c->reg.dir, c->reg.dir, vec4(e));
}
예제 #5
0
static void emit_points(struct brw_clip_compile *c,
			bool do_offset )
{
   struct brw_compile *p = &c->func;

   struct brw_indirect v0 = brw_indirect(0, 0);
   struct brw_indirect v0ptr = brw_indirect(2, 0);

   brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
   brw_MOV(p, get_addr_reg(v0ptr), brw_address(c->reg.inlist));

   brw_DO(p, BRW_EXECUTE_1);
   {
      brw_MOV(p, get_addr_reg(v0), deref_1uw(v0ptr, 0));
      brw_ADD(p, get_addr_reg(v0ptr), get_addr_reg(v0ptr), brw_imm_uw(2));

      /* draw if edgeflag != 0 
       */
      brw_CMP(p, 
	      vec1(brw_null_reg()), BRW_CONDITIONAL_NZ, 
	      deref_1f(v0, brw_vert_result_to_offset(&c->vue_map,
                                                     VARYING_SLOT_EDGE)),
	      brw_imm_f(0));
      brw_IF(p, BRW_EXECUTE_1);
      {
	 if (do_offset)
	    apply_one_offset(c, v0);

	 brw_clip_emit_vue(c, v0, 1, 0,
                           (_3DPRIM_POINTLIST << URB_WRITE_PRIM_TYPE_SHIFT)
                           | URB_WRITE_PRIM_START | URB_WRITE_PRIM_END);
      }
      brw_ENDIF(p);

      brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
      brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
   }
   brw_WHILE(p);
}
예제 #6
0
static void brw_clip_test( struct brw_clip_compile *c )
{
    struct brw_reg t = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
    struct brw_reg t1 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
    struct brw_reg t2 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
    struct brw_reg t3 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);

    struct brw_reg v0 = get_tmp(c);
    struct brw_reg v1 = get_tmp(c);
    struct brw_reg v2 = get_tmp(c);

    struct brw_indirect vt0 = brw_indirect(0, 0);
    struct brw_indirect vt1 = brw_indirect(1, 0);
    struct brw_indirect vt2 = brw_indirect(2, 0);

    struct brw_compile *p = &c->func;
    struct brw_reg tmp0 = c->reg.loopcount; /* handy temporary */

    GLuint hpos_offset = brw_vert_result_to_offset(&c->vue_map,
                                                   VERT_RESULT_HPOS);

    brw_MOV(p, get_addr_reg(vt0), brw_address(c->reg.vertex[0]));
    brw_MOV(p, get_addr_reg(vt1), brw_address(c->reg.vertex[1]));
    brw_MOV(p, get_addr_reg(vt2), brw_address(c->reg.vertex[2]));
    brw_MOV(p, v0, deref_4f(vt0, hpos_offset));
    brw_MOV(p, v1, deref_4f(vt1, hpos_offset));
    brw_MOV(p, v2, deref_4f(vt2, hpos_offset));
    brw_AND(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(~0x3f));

    /* test nearz, xmin, ymin plane */
    /* clip.xyz < -clip.w */
    brw_CMP(p, t1, BRW_CONDITIONAL_L, v0, negate(get_element(v0, 3))); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t2, BRW_CONDITIONAL_L, v1, negate(get_element(v1, 3))); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t3, BRW_CONDITIONAL_L, v2, negate(get_element(v2, 3))); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    /* All vertices are outside of a plane, rejected */
    brw_AND(p, t, t1, t2);
    brw_AND(p, t, t, t3);
    brw_OR(p, tmp0, get_element(t, 0), get_element(t, 1));
    brw_OR(p, tmp0, tmp0, get_element(t, 2));
    brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
    brw_AND(p, brw_null_reg(), tmp0, brw_imm_ud(0x1));
    brw_IF(p, BRW_EXECUTE_1);
    {
        brw_clip_kill_thread(c);
    }
    brw_ENDIF(p);
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    /* some vertices are inside a plane, some are outside,need to clip */
    brw_XOR(p, t, t1, t2);
    brw_XOR(p, t1, t2, t3);
    brw_OR(p, t, t, t1);
    brw_AND(p, t, t, brw_imm_ud(0x1));
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 0), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<5)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 1), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<3)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 2), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<1)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    /* test farz, xmax, ymax plane */
    /* clip.xyz > clip.w */
    brw_CMP(p, t1, BRW_CONDITIONAL_G, v0, get_element(v0, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t2, BRW_CONDITIONAL_G, v1, get_element(v1, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t3, BRW_CONDITIONAL_G, v2, get_element(v2, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    /* All vertices are outside of a plane, rejected */
    brw_AND(p, t, t1, t2);
    brw_AND(p, t, t, t3);
    brw_OR(p, tmp0, get_element(t, 0), get_element(t, 1));
    brw_OR(p, tmp0, tmp0, get_element(t, 2));
    brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
    brw_AND(p, brw_null_reg(), tmp0, brw_imm_ud(0x1));
    brw_IF(p, BRW_EXECUTE_1);
    {
        brw_clip_kill_thread(c);
    }
    brw_ENDIF(p);
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    /* some vertices are inside a plane, some are outside,need to clip */
    brw_XOR(p, t, t1, t2);
    brw_XOR(p, t1, t2, t3);
    brw_OR(p, t, t, t1);
    brw_AND(p, t, t, brw_imm_ud(0x1));
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 0), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<4)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 1), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<2)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
            get_element(t, 2), brw_imm_ud(0));
    brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<0)));
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    release_tmps(c);
}
예제 #7
0
/* Use mesa's clipping algorithms, translated to GEN4 assembly.
 */
void brw_clip_tri( struct brw_clip_compile *c )
{
   struct brw_compile *p = &c->func;
   struct brw_indirect vtx = brw_indirect(0, 0);
   struct brw_indirect vtxPrev = brw_indirect(1, 0);
   struct brw_indirect vtxOut = brw_indirect(2, 0);
   struct brw_indirect plane_ptr = brw_indirect(3, 0);
   struct brw_indirect inlist_ptr = brw_indirect(4, 0);
   struct brw_indirect outlist_ptr = brw_indirect(5, 0);
   struct brw_indirect freelist_ptr = brw_indirect(6, 0);
   GLuint hpos_offset = brw_vert_result_to_offset(&c->vue_map,
                                                  VERT_RESULT_HPOS);
   
   brw_MOV(p, get_addr_reg(vtxPrev),     brw_address(c->reg.vertex[2]) );
   brw_MOV(p, get_addr_reg(plane_ptr),   brw_clip_plane0_address(c));
   brw_MOV(p, get_addr_reg(inlist_ptr),  brw_address(c->reg.inlist));
   brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));

   brw_MOV(p, get_addr_reg(freelist_ptr), brw_address(c->reg.vertex[3]) );

   brw_DO(p, BRW_EXECUTE_1);
   {
      /* if (planemask & 1)
       */
      brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
      brw_AND(p, vec1(brw_null_reg()), c->reg.planemask, brw_imm_ud(1));
      
      brw_IF(p, BRW_EXECUTE_1);
      {
	 /* vtxOut = freelist_ptr++ 
	  */
	 brw_MOV(p, get_addr_reg(vtxOut),       get_addr_reg(freelist_ptr) );
	 brw_ADD(p, get_addr_reg(freelist_ptr), get_addr_reg(freelist_ptr), brw_imm_uw(c->nr_regs * REG_SIZE));

	 if (c->key.nr_userclip)
	    brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
	 else
	    brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
	    
	 brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
	 brw_MOV(p, c->reg.nr_verts, brw_imm_ud(0));

	 brw_DO(p, BRW_EXECUTE_1);
	 {
	    /* vtx = *input_ptr;
	     */
	    brw_MOV(p, get_addr_reg(vtx), deref_1uw(inlist_ptr, 0));

	    /* IS_NEGATIVE(prev) */
	    brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
	    brw_DP4(p, vec4(c->reg.dpPrev), deref_4f(vtxPrev, hpos_offset), c->reg.plane_equation);
	    brw_IF(p, BRW_EXECUTE_1);
	    {
	       /* IS_POSITIVE(next)
		*/
	       brw_set_conditionalmod(p, BRW_CONDITIONAL_GE);
	       brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, hpos_offset), c->reg.plane_equation);
	       brw_IF(p, BRW_EXECUTE_1);
	       {

		  /* Coming back in.
		   */
		  brw_ADD(p, c->reg.t, c->reg.dpPrev, negate(c->reg.dp));
		  brw_math_invert(p, c->reg.t, c->reg.t);
		  brw_MUL(p, c->reg.t, c->reg.t, c->reg.dpPrev);

		  /* If (vtxOut == 0) vtxOut = vtxPrev
		   */
		  brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
		  brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtxPrev) );
		  brw_set_predicate_control(p, BRW_PREDICATE_NONE);

		  brw_clip_interp_vertex(c, vtxOut, vtxPrev, vtx, c->reg.t, false);

		  /* *outlist_ptr++ = vtxOut;
		   * nr_verts++; 
		   * vtxOut = 0;
		   */
		  brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
		  brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
		  brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
		  brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
	       }
	       brw_ENDIF(p);
	       
	    }
	    brw_ELSE(p);
	    {
	       /* *outlist_ptr++ = vtxPrev;
		* nr_verts++;
		*/
	       brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxPrev));
	       brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
	       brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));

	       /* IS_NEGATIVE(next)
		*/
	       brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
	       brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, hpos_offset), c->reg.plane_equation);
	       brw_IF(p, BRW_EXECUTE_1);
	       {
		  /* Going out of bounds.  Avoid division by zero as we
		   * know dp != dpPrev from DIFFERENT_SIGNS, above.
		   */
		  brw_ADD(p, c->reg.t, c->reg.dp, negate(c->reg.dpPrev));
		  brw_math_invert(p, c->reg.t, c->reg.t);
		  brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp);

		  /* If (vtxOut == 0) vtxOut = vtx
		   */
		  brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
		  brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtx) );
		  brw_set_predicate_control(p, BRW_PREDICATE_NONE);

		  brw_clip_interp_vertex(c, vtxOut, vtx, vtxPrev, c->reg.t, true);

		  /* *outlist_ptr++ = vtxOut;
		   * nr_verts++; 
		   * vtxOut = 0;
		   */
		  brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
		  brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
		  brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
		  brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
	       } 	       
	       brw_ENDIF(p);
	    }
	    brw_ENDIF(p);
	    
	    /* vtxPrev = vtx;
	     * inlist_ptr++;
	     */
	    brw_MOV(p, get_addr_reg(vtxPrev), get_addr_reg(vtx));
	    brw_ADD(p, get_addr_reg(inlist_ptr), get_addr_reg(inlist_ptr), brw_imm_uw(sizeof(short)));

	    /* while (--loopcount != 0)
	     */
	    brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
	    brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
	 } 
	 brw_WHILE(p);

	 /* vtxPrev = *(outlist_ptr-1)  OR: outlist[nr_verts-1]
	  * inlist = outlist
	  * inlist_ptr = &inlist[0]
	  * outlist_ptr = &outlist[0]
	  */
	 brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_w(-2));
	 brw_MOV(p, get_addr_reg(vtxPrev), deref_1uw(outlist_ptr, 0));
	 brw_MOV(p, brw_vec8_grf(c->reg.inlist.nr, 0), brw_vec8_grf(c->reg.outlist.nr, 0));
	 brw_MOV(p, get_addr_reg(inlist_ptr), brw_address(c->reg.inlist));
	 brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));
      }
      brw_ENDIF(p);
      
      /* plane_ptr++;
       */
      brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));

      /* nr_verts >= 3 
       */
      brw_CMP(p,
	      vec1(brw_null_reg()),
	      BRW_CONDITIONAL_GE,
	      c->reg.nr_verts,
	      brw_imm_ud(3));
   
      /* && (planemask>>=1) != 0
       */
      brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
      brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
   }
   brw_WHILE(p);
}
예제 #8
0
/***********************************************************************
 * Output clipped polygon as an unfilled primitive:
 */
static void emit_lines(struct brw_clip_compile *c,
		       bool do_offset)
{
   struct brw_compile *p = &c->func;
   struct brw_indirect v0 = brw_indirect(0, 0);
   struct brw_indirect v1 = brw_indirect(1, 0);
   struct brw_indirect v0ptr = brw_indirect(2, 0);
   struct brw_indirect v1ptr = brw_indirect(3, 0);

   /* Need a seperate loop for offset:
    */
   if (do_offset) {
      brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
      brw_MOV(p, get_addr_reg(v0ptr), brw_address(c->reg.inlist));

      brw_DO(p, BRW_EXECUTE_1);
      {
	 brw_MOV(p, get_addr_reg(v0), deref_1uw(v0ptr, 0));
	 brw_ADD(p, get_addr_reg(v0ptr), get_addr_reg(v0ptr), brw_imm_uw(2));
	    
	 apply_one_offset(c, v0);
	    
	 brw_set_conditionalmod(p, BRW_CONDITIONAL_G);
	 brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
      }
      brw_WHILE(p);
   }

   /* v1ptr = &inlist[nr_verts]
    * *v1ptr = v0
    */
   brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
   brw_MOV(p, get_addr_reg(v0ptr), brw_address(c->reg.inlist));
   brw_ADD(p, get_addr_reg(v1ptr), get_addr_reg(v0ptr), retype(c->reg.nr_verts, BRW_REGISTER_TYPE_UW));
   brw_ADD(p, get_addr_reg(v1ptr), get_addr_reg(v1ptr), retype(c->reg.nr_verts, BRW_REGISTER_TYPE_UW));
   brw_MOV(p, deref_1uw(v1ptr, 0), deref_1uw(v0ptr, 0));

   brw_DO(p, BRW_EXECUTE_1);
   {
      brw_MOV(p, get_addr_reg(v0), deref_1uw(v0ptr, 0));
      brw_MOV(p, get_addr_reg(v1), deref_1uw(v0ptr, 2));
      brw_ADD(p, get_addr_reg(v0ptr), get_addr_reg(v0ptr), brw_imm_uw(2));

      /* draw edge if edgeflag != 0 */
      brw_CMP(p, 
	      vec1(brw_null_reg()), BRW_CONDITIONAL_NZ, 
	      deref_1f(v0, brw_vert_result_to_offset(&c->vue_map,
                                                     VARYING_SLOT_EDGE)),
	      brw_imm_f(0));
      brw_IF(p, BRW_EXECUTE_1);
      {
	 brw_clip_emit_vue(c, v0, 1, 0,
                           (_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
                           | URB_WRITE_PRIM_START);
	 brw_clip_emit_vue(c, v1, 1, 0,
                           (_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
                           | URB_WRITE_PRIM_END);
      }
      brw_ENDIF(p);

      brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
      brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
   }
   brw_WHILE(p);
}