C++ emit_op2函数代码示例

/**
 * Point size attenuation computation.
 */
static void build_atten_pointsize( struct tnl_program *p )
{
   struct ureg eye = get_eye_position_z(p);
   struct ureg state_size = register_param1(p, STATE_POINT_SIZE);
   struct ureg state_attenuation = register_param1(p, STATE_POINT_ATTENUATION);
   struct ureg out = register_output(p, VERT_RESULT_PSIZ);
   struct ureg ut = get_temp(p);

   /* dist = |eyez| */
   emit_op1(p, OPCODE_ABS, ut, WRITEMASK_Y, swizzle1(eye, Z));
   /* p1 + dist * (p2 + dist * p3); */
   emit_op3(p, OPCODE_MAD, ut, WRITEMASK_X, swizzle1(ut, Y),
		swizzle1(state_attenuation, Z), swizzle1(state_attenuation, Y));
   emit_op3(p, OPCODE_MAD, ut, WRITEMASK_X, swizzle1(ut, Y),
		ut, swizzle1(state_attenuation, X));

   /* 1 / sqrt(factor) */
   emit_op1(p, OPCODE_RSQ, ut, WRITEMASK_X, ut );

#if 0
   /* out = pointSize / sqrt(factor) */
   emit_op2(p, OPCODE_MUL, out, WRITEMASK_X, ut, state_size);
#else
   /* this is a good place to clamp the point size since there's likely
    * no hardware registers to clamp point size at rasterization time.
    */
   emit_op2(p, OPCODE_MUL, ut, WRITEMASK_X, ut, state_size);
   emit_op2(p, OPCODE_MAX, ut, WRITEMASK_X, ut, swizzle1(state_size, Y));
   emit_op2(p, OPCODE_MIN, out, WRITEMASK_X, ut, swizzle1(state_size, Z));
#endif

   release_temp(p, ut);
}

/* Seems like it could be tighter:
 */
static void build_pointsize( struct tnl_program *p )
{
   struct ureg eye = get_eye_position(p);
   struct ureg state_size = register_param1(p, STATE_POINT_SIZE);
   struct ureg state_attenuation = register_param1(p, STATE_POINT_ATTENUATION);
   struct ureg out = register_output(p, VERT_RESULT_PSIZ);
   struct ureg ut = get_temp(p);

   /* 1, Z, Z * Z, 1 */      
   emit_op1(p, OPCODE_MOV, ut, WRITEMASK_XW, swizzle1(get_identity_param(p), W));
   emit_op1(p, OPCODE_ABS, ut, WRITEMASK_YZ, swizzle1(eye, Z));
   emit_op2(p, OPCODE_MUL, ut, WRITEMASK_Z, ut, ut);


   /* p1 +  p2 * dist + p3 * dist * dist, 0 */
   emit_op2(p, OPCODE_DP3, ut, WRITEMASK_X, ut, state_attenuation);

   /* 1 / sqrt(factor) */
   emit_op1(p, OPCODE_RSQ, ut, WRITEMASK_X, ut ); 

   /* ut = pointSize / factor */
   emit_op2(p, OPCODE_MUL, ut, WRITEMASK_X, ut, state_size); 

   /* Clamp to min/max - state_size.[yz]
    */
   emit_op2(p, OPCODE_MAX, ut, WRITEMASK_X, ut, swizzle1(state_size, Y)); 
   emit_op2(p, OPCODE_MIN, out, 0, swizzle1(ut, X), swizzle1(state_size, Z)); 
   
   release_temp(p, ut);
}

static void build_pointsize( struct tnl_program *p )
{
   struct ureg eye = get_eye_position(p);
   struct ureg state_size = register_param1(p, STATE_POINT_SIZE);
   struct ureg state_attenuation = register_param1(p, STATE_POINT_ATTENUATION);
   struct ureg out = register_output(p, VERT_RESULT_PSIZ);
   struct ureg ut = get_temp(p);

   /* dist = |eyez| */
   emit_op1(p, OPCODE_ABS, ut, WRITEMASK_Y, swizzle1(eye, Z));
   /* p1 + dist * (p2 + dist * p3); */
   emit_op3(p, OPCODE_MAD, ut, WRITEMASK_X, swizzle1(ut, Y),
		swizzle1(state_attenuation, Z), swizzle1(state_attenuation, Y));
   emit_op3(p, OPCODE_MAD, ut, WRITEMASK_X, swizzle1(ut, Y),
		ut, swizzle1(state_attenuation, X));

   /* 1 / sqrt(factor) */
   emit_op1(p, OPCODE_RSQ, ut, WRITEMASK_X, ut );

#if 1
   /* out = pointSize / sqrt(factor) */
   emit_op2(p, OPCODE_MUL, out, WRITEMASK_X, ut, state_size);
#else
   /* not sure, might make sense to do clamping here,
      but it's not done in t_vb_points neither */
   emit_op2(p, OPCODE_MUL, ut, WRITEMASK_X, ut, state_size);
   emit_op2(p, OPCODE_MAX, ut, WRITEMASK_X, ut, swizzle1(state_size, Y));
   emit_op2(p, OPCODE_MIN, out, WRITEMASK_X, ut, swizzle1(state_size, Z));
#endif

   release_temp(p, ut);
}

static void emit_normalize_vec3( struct tnl_program *p,
				 struct ureg dest,
				 struct ureg src )
{
   emit_op2(p, OPCODE_DP3, dest, WRITEMASK_W, src, src);
   emit_op1(p, OPCODE_RSQ, dest, WRITEMASK_W, swizzle1(dest,W));
   emit_op2(p, OPCODE_MUL, dest, WRITEMASK_XYZ, src, swizzle1(dest,W));
}

static void emit_matrix_transform_vec3( struct tnl_program *p,
					struct ureg dest,
					const struct ureg *mat,
					struct ureg src)
{
   emit_op2(p, OPCODE_DP3, dest, WRITEMASK_X, src, mat[0]);
   emit_op2(p, OPCODE_DP3, dest, WRITEMASK_Y, src, mat[1]);
   emit_op2(p, OPCODE_DP3, dest, WRITEMASK_Z, src, mat[2]);
}

static void build_fog( struct tnl_program *p )
{
   struct ureg fog = register_output(p, VERT_RESULT_FOGC);
   struct ureg input;
   GLuint useabs = p->state->fog_source_is_depth && p->state->fog_option &&
		   (p->state->fog_option != FOG_EXP2);

   if (p->state->fog_source_is_depth) {
      input = swizzle1(get_eye_position(p), Z);
   }
   else {
      input = swizzle1(register_input(p, VERT_ATTRIB_FOG), X);
   }

   if (p->state->fog_option &&
       p->state->tnl_do_vertex_fog) {
      struct ureg params = register_param2(p, STATE_INTERNAL,
					   STATE_FOG_PARAMS_OPTIMIZED);
      struct ureg tmp = get_temp(p);
      struct ureg id = get_identity_param(p);

      emit_op1(p, OPCODE_MOV, fog, 0, id);

      if (useabs) {
	 emit_op1(p, OPCODE_ABS, tmp, 0, input);
      }

      switch (p->state->fog_option) {
      case FOG_LINEAR: {
	 emit_op3(p, OPCODE_MAD, tmp, 0, useabs ? tmp : input,
			swizzle1(params,X), swizzle1(params,Y));
	 emit_op2(p, OPCODE_MAX, tmp, 0, tmp, swizzle1(id,X)); /* saturate */
	 emit_op2(p, OPCODE_MIN, fog, WRITEMASK_X, tmp, swizzle1(id,W));
	 break;
      }
      case FOG_EXP:
	 emit_op2(p, OPCODE_MUL, tmp, 0, useabs ? tmp : input,
			swizzle1(params,Z));
	 emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, ureg_negate(tmp));
	 break;
      case FOG_EXP2:
	 emit_op2(p, OPCODE_MUL, tmp, 0, input, swizzle1(params,W));
	 emit_op2(p, OPCODE_MUL, tmp, 0, tmp, tmp);
	 emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, ureg_negate(tmp));
	 break;
      }

      release_temp(p, tmp);
   }
   else {
      /* results = incoming fog coords (compute fog per-fragment later) 
       *
       * KW:  Is it really necessary to do anything in this case?
       */
      emit_op1(p, useabs ? OPCODE_ABS : OPCODE_MOV, fog, 0, input);
   }
}

static void build_fog( struct tnl_program *p )
{
   struct ureg fog = register_output(p, VERT_RESULT_FOGC);
   struct ureg input;

   if (p->state->fog_source_is_depth) {
      input = swizzle1(get_eye_position(p), Z);
   }
   else {
      input = swizzle1(register_input(p, VERT_ATTRIB_FOG), X);
   }

   if (p->state->fog_mode && p->state->tnl_do_vertex_fog) {
      struct ureg params = register_param2(p, STATE_INTERNAL,
					   STATE_FOG_PARAMS_OPTIMIZED);
      struct ureg tmp = get_temp(p);
      GLboolean useabs = (p->state->fog_mode != FOG_EXP2);

      if (useabs) {
	 emit_op1(p, OPCODE_ABS, tmp, 0, input);
      }

      switch (p->state->fog_mode) {
      case FOG_LINEAR: {
	 struct ureg id = get_identity_param(p);
	 emit_op3(p, OPCODE_MAD, tmp, 0, useabs ? tmp : input,
			swizzle1(params,X), swizzle1(params,Y));
	 emit_op2(p, OPCODE_MAX, tmp, 0, tmp, swizzle1(id,X)); /* saturate */
	 emit_op2(p, OPCODE_MIN, fog, WRITEMASK_X, tmp, swizzle1(id,W));
	 break;
      }
      case FOG_EXP:
	 emit_op2(p, OPCODE_MUL, tmp, 0, useabs ? tmp : input,
			swizzle1(params,Z));
	 emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, negate(tmp));
	 break;
      case FOG_EXP2:
	 emit_op2(p, OPCODE_MUL, tmp, 0, input, swizzle1(params,W));
	 emit_op2(p, OPCODE_MUL, tmp, 0, tmp, tmp);
	 emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, negate(tmp));
	 break;
      }

      release_temp(p, tmp);
   }
   else {
      /* results = incoming fog coords (compute fog per-fragment later) 
       *
       * KW:  Is it really necessary to do anything in this case?
       * BP: Yes, we always need to compute the absolute value, unless
       * we want to push that down into the fragment program...
       */
      GLboolean useabs = GL_TRUE;
      emit_op1(p, useabs ? OPCODE_ABS : OPCODE_MOV, fog, WRITEMASK_X, input);
   }
}

static void emit_normalize_vec3( struct tnl_program *p,
				 struct ureg dest,
				 struct ureg src )
{
   struct ureg tmp = get_temp(p);
   emit_op2(p, OPCODE_DP3, tmp, WRITEMASK_X, src, src);
   emit_op1(p, OPCODE_RSQ, tmp, WRITEMASK_X, tmp);
   emit_op2(p, OPCODE_MUL, dest, 0, src, swizzle1(tmp, X));
   release_temp(p, tmp);
}

static void emit_normalize_vec3( struct tnl_program *p,
				 struct ureg dest,
				 struct ureg src )
{
#if 0
   /* XXX use this when drivers are ready for NRM3 */
   emit_op1(p, OPCODE_NRM3, dest, WRITEMASK_XYZ, src);
#else
   struct ureg tmp = get_temp(p);
   emit_op2(p, OPCODE_DP3, tmp, WRITEMASK_X, src, src);
   emit_op1(p, OPCODE_RSQ, tmp, WRITEMASK_X, tmp);
   emit_op2(p, OPCODE_MUL, dest, 0, src, swizzle1(tmp, X));
   release_temp(p, tmp);
#endif
}

static struct ureg get_eye_normal( struct tnl_program *p )
{
   if (is_undef(p->eye_normal)) {
      struct ureg normal = register_input(p, VERT_ATTRIB_NORMAL );
      struct ureg mvinv[3];

      register_matrix_param5( p, STATE_MODELVIEW_MATRIX, 0, 0, 2,
			      STATE_MATRIX_INVTRANS, mvinv );

      p->eye_normal = reserve_temp(p);

      /* Transform to eye space:
       */
      emit_matrix_transform_vec3( p, p->eye_normal, mvinv, normal );

      /* Normalize/Rescale:
       */
      if (p->state->normalize) {
	 emit_normalize_vec3( p, p->eye_normal, p->eye_normal );
      }
      else if (p->state->rescale_normals) {
	 struct ureg rescale = register_param2(p, STATE_INTERNAL,
					       STATE_NORMAL_SCALE);

	 emit_op2( p, OPCODE_MUL, p->eye_normal, 0, p->eye_normal, 
		   swizzle1(rescale, X));
      }
   }

   return p->eye_normal;
}

static void build_fog( struct tnl_program *p )
{
   struct ureg fog = register_output(p, VARYING_SLOT_FOGC);
   struct ureg input;

   if (p->state->fog_source_is_depth) {

      switch (p->state->fog_distance_mode) {
      case FDM_EYE_RADIAL: /* Z = sqrt(Xe*Xe + Ye*Ye + Ze*Ze) */
	input = get_eye_position(p);
	emit_op2(p, OPCODE_DP3, fog, WRITEMASK_X, input, input);
	emit_op1(p, OPCODE_RSQ, fog, WRITEMASK_X, fog);
	emit_op1(p, OPCODE_RCP, fog, WRITEMASK_X, fog);
	break;
      case FDM_EYE_PLANE: /* Z = Ze */
	input = get_eye_position_z(p);
	emit_op1(p, OPCODE_MOV, fog, WRITEMASK_X, input);
	break;
      case FDM_EYE_PLANE_ABS: /* Z = abs(Ze) */
	input = get_eye_position_z(p);
	emit_op1(p, OPCODE_ABS, fog, WRITEMASK_X, input);
	break;
      default: assert(0); break; /* can't happen */
      }

   }
   else {
      input = swizzle1(register_input(p, VERT_ATTRIB_FOG), X);
      emit_op1(p, OPCODE_ABS, fog, WRITEMASK_X, input);
   }

   emit_op1(p, OPCODE_MOV, fog, WRITEMASK_YZW, get_identity_param(p));
}

static void build_reflect_texgen( struct tnl_program *p,
				  struct ureg dest,
				  GLuint writemask )
{
   struct ureg normal = get_transformed_normal(p);
   struct ureg eye_hat = get_eye_position_normalized(p);
   struct ureg tmp = get_temp(p);

   /* n.u */
   emit_op2(p, OPCODE_DP3, tmp, 0, normal, eye_hat);
   /* 2n.u */
   emit_op2(p, OPCODE_ADD, tmp, 0, tmp, tmp);
   /* (-2n.u)n + u */
   emit_op3(p, OPCODE_MAD, dest, writemask, negate(tmp), normal, eye_hat);

   release_temp(p, tmp);
}

/**
 * Compute:
 *   lit.y = MAX(0, dots.x)
 *   lit.z = SLT(0, dots.x)
 */
static void emit_degenerate_lit( struct tnl_program *p,
                                 struct ureg lit,
                                 struct ureg dots )
{
   struct ureg id = get_identity_param(p);  /* id = {0,0,0,1} */

   /* Note that lit.x & lit.w will not be examined.  Note also that
    * dots.xyzw == dots.xxxx.
    */

   /* MAX lit, id, dots;
    */
   emit_op2(p, OPCODE_MAX, lit, WRITEMASK_XYZW, id, dots);

   /* result[2] = (in > 0 ? 1 : 0)
    * SLT lit.z, id.z, dots;   # lit.z = (0 < dots.z) ? 1 : 0
    */
   emit_op2(p, OPCODE_SLT, lit, WRITEMASK_Z, swizzle1(id,Z), dots);
}

static struct ureg calculate_light_attenuation( struct tnl_program *p,
						GLuint i,
						struct ureg VPpli,
						struct ureg dist )
{
   struct ureg attenuation = register_param3(p, STATE_LIGHT, i,
					     STATE_ATTENUATION);
   struct ureg att = undef;

   /* Calculate spot attenuation:
    */
   if (!p->state->unit[i].light_spotcutoff_is_180) {
      struct ureg spot_dir_norm = register_param3(p, STATE_INTERNAL,
						  STATE_LIGHT_SPOT_DIR_NORMALIZED, i);
      struct ureg spot = get_temp(p);
      struct ureg slt = get_temp(p);

      att = get_temp(p);

      emit_op2(p, OPCODE_DP3, spot, 0, negate(VPpli), spot_dir_norm);
      emit_op2(p, OPCODE_SLT, slt, 0, swizzle1(spot_dir_norm,W), spot);
      emit_op1(p, OPCODE_ABS, spot, 0, spot);
      emit_op2(p, OPCODE_POW, spot, 0, spot, swizzle1(attenuation, W));
      emit_op2(p, OPCODE_MUL, att, 0, slt, spot);

      release_temp(p, spot);
      release_temp(p, slt);
   }

   /* Calculate distance attenuation(See formula (2.4) at glspec 2.1 page 62):
    *
    * Skip the calucation when _dist_ is undefined(light_eyepos3_is_zero)
    */
   if (p->state->unit[i].light_attenuated && !is_undef(dist)) {
      if (is_undef(att))
         att = get_temp(p);
      /* 1/d,d,d,1/d */
      emit_op1(p, OPCODE_RCP, dist, WRITEMASK_YZ, dist);
      /* 1,d,d*d,1/d */
      emit_op2(p, OPCODE_MUL, dist, WRITEMASK_XZ, dist, swizzle1(dist,Y));
      /* 1/dist-atten */
      emit_op2(p, OPCODE_DP3, dist, 0, attenuation, dist);

      if (!p->state->unit[i].light_spotcutoff_is_180) {
	 /* dist-atten */
	 emit_op1(p, OPCODE_RCP, dist, 0, dist);
	 /* spot-atten * dist-atten */
	 emit_op2(p, OPCODE_MUL, att, 0, dist, att);
      }
      else {
	 /* dist-atten */
	 emit_op1(p, OPCODE_RCP, att, 0, dist);
      }
   }

   return att;
}

static void build_sphere_texgen( struct tnl_program *p,
				 struct ureg dest,
				 GLuint writemask )
{
   struct ureg normal = get_transformed_normal(p);
   struct ureg eye_hat = get_eye_position_normalized(p);
   struct ureg tmp = get_temp(p);
   struct ureg half = register_scalar_const(p, .5);
   struct ureg r = get_temp(p);
   struct ureg inv_m = get_temp(p);
   struct ureg id = get_identity_param(p);

   /* Could share the above calculations, but it would be
    * a fairly odd state for someone to set (both sphere and
    * reflection active for different texture coordinate
    * components.  Of course - if two texture units enable
    * reflect and/or sphere, things start to tilt in favour
    * of seperating this out:
    */

   /* n.u */
   emit_op2(p, OPCODE_DP3, tmp, 0, normal, eye_hat);
   /* 2n.u */
   emit_op2(p, OPCODE_ADD, tmp, 0, tmp, tmp);
   /* (-2n.u)n + u */
   emit_op3(p, OPCODE_MAD, r, 0, negate(tmp), normal, eye_hat);
   /* r + 0,0,1 */
   emit_op2(p, OPCODE_ADD, tmp, 0, r, swizzle(id,X,Y,W,Z));
   /* rx^2 + ry^2 + (rz+1)^2 */
   emit_op2(p, OPCODE_DP3, tmp, 0, tmp, tmp);
   /* 2/m */
   emit_op1(p, OPCODE_RSQ, tmp, 0, tmp);
   /* 1/m */
   emit_op2(p, OPCODE_MUL, inv_m, 0, tmp, half);
   /* r/m + 1/2 */
   emit_op3(p, OPCODE_MAD, dest, writemask, r, inv_m, half);

   release_temp(p, tmp);
   release_temp(p, r);
   release_temp(p, inv_m);
}