brw_clip_tri.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

		  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, next_test);
	       
	    }
	    prev_test = brw_ELSE(p, prev_test);
	    {
	       /* *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, c->offset[VERT_RESULT_HPOS]), c->reg.plane_equation);
	       next_test = 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, GL_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, next_test);
	    }
	    brw_ENDIF(p, prev_test);
	    
	    /* 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, vertex_loop);

	 /* 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_active);
      
      /* 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, plane_loop);
}



void brw_clip_tri_emit_polygon(struct brw_clip_compile *c)
{
   struct brw_compile *p = &c->func;
   struct brw_instruction *loop, *if_insn;

   /* for (loopcount = nr_verts-2; loopcount > 0; loopcount--)
    */
   brw_set_conditionalmod(p, BRW_CONDITIONAL_G);
   brw_ADD(p,
	   c->reg.loopcount,
	   c->reg.nr_verts,
	   brw_imm_d(-2));

   if_insn = brw_IF(p, BRW_EXECUTE_1);
   {
      struct brw_indirect v0 = brw_indirect(0, 0);
      struct brw_indirect vptr = brw_indirect(1, 0);

      brw_MOV(p, get_addr_reg(vptr), brw_address(c->reg.inlist));
      brw_MOV(p, get_addr_reg(v0), deref_1uw(vptr, 0));

      brw_clip_emit_vue(c, v0, 1, 0, ((_3DPRIM_TRIFAN << 2) | R02_PRIM_START));
      
      brw_ADD(p, get_addr_reg(vptr), get_addr_reg(vptr), brw_imm_uw(2));
      brw_MOV(p, get_addr_reg(v0), deref_1uw(vptr, 0));

      loop = brw_DO(p, BRW_EXECUTE_1);
      {
	 brw_clip_emit_vue(c, v0, 1, 0, (_3DPRIM_TRIFAN << 2));
  
	 brw_ADD(p, get_addr_reg(vptr), get_addr_reg(vptr), brw_imm_uw(2));
	 brw_MOV(p, get_addr_reg(v0), deref_1uw(vptr, 0));

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

      brw_clip_emit_vue(c, v0, 0, 1, ((_3DPRIM_TRIFAN << 2) | R02_PRIM_END));
   }
   brw_ENDIF(p, if_insn);
}

static void do_clip_tri( struct brw_clip_compile *c )
{
   brw_clip_init_planes(c);

   brw_clip_tri(c);
}


static void maybe_do_clip_tri( struct brw_clip_compile *c )
{
   struct brw_compile *p = &c->func;
   struct brw_instruction *do_clip;

   brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_NZ, c->reg.planemask, brw_imm_ud(0));
   do_clip = brw_IF(p, BRW_EXECUTE_1);
   {
      do_clip_tri(c);
   }
   brw_ENDIF(p, do_clip);
}

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;

    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, c->offset[VERT_RESULT_HPOS]));
    brw_MOV(p, v1, deref_4f(vt1, c->offset[VERT_RESULT_HPOS]));
    brw_MOV(p, v2, deref_4f(vt2, c->offset[VERT_RESULT_HPOS]));

    /* test nearz, xmin, ymin plane */
    brw_CMP(p, t1, BRW_CONDITIONAL_LE, negate(v0), get_element(v0, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t2, BRW_CONDITIONAL_LE, negate(v1), get_element(v1, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t3, BRW_CONDITIONAL_LE, negate(v2), get_element(v2, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_XOR(p, t, t1, t2);
    brw_XOR(p, t1, t2, t3);
    brw_OR(p, t, t, t1);

    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 */
    brw_CMP(p, t1, BRW_CONDITIONAL_L, v0, get_element(v0, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t2, BRW_CONDITIONAL_L, v1, get_element(v1, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);
    brw_CMP(p, t3, BRW_CONDITIONAL_L, v2, get_element(v2, 3)); 
    brw_set_predicate_control(p, BRW_PREDICATE_NONE);

    brw_XOR(p, t, t1, t2);
    brw_XOR(p, t1, t2, t3);
    brw_OR(p, t, t, t1);

    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);
}


void brw_emit_tri_clip( struct brw_clip_compile *c )
{
   struct brw_instruction *neg_rhw;
   struct brw_compile *p = &c->func;
   brw_clip_tri_alloc_regs(c, 3 + c->key.nr_userclip + 6);
   brw_clip_tri_init_vertices(c);
   brw_clip_init_clipmask(c);

   /* if -ve rhw workaround bit is set, 
      do cliptest */
   if (!(BRW_IS_GM45(p->brw) || BRW_IS_G4X(p->brw))) {
      brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
      brw_AND(p, brw_null_reg(), get_element_ud(c->reg.R0, 2), 
              brw_imm_ud(1<<20));
      neg_rhw = brw_IF(p, BRW_EXECUTE_1); 
      {
         brw_clip_test(c);
      }
      brw_ENDIF(p, neg_rhw);
   }
   /* Can't push into do_clip_tri because with polygon (or quad)
    * flatshading, need to apply the flatshade here because we don't
    * respect the PV when converting to trifan for emit:
    */
   if (c->key.do_flat_shading) 
      brw_clip_tri_flat_shade(c); 
      
   if (c->key.clip_mode == BRW_CLIPMODE_NORMAL)
      do_clip_tri(c);
   else 
      maybe_do_clip_tri(c);
      
   brw_clip_tri_emit_polygon(c);

   /* Send an empty message to kill the thread:
    */
   brw_clip_kill_thread(c);
}