ttraster.c

神龙卡开发原代码

/****************************************************************************/
/*                                                                          */
/* Function:    New_Profile                                                 */
/*                                                                          */
/* Description: Creates a new Profile in the render pool.                   */
/*                                                                          */
/* Input:       aState   state/orientation of the new Profile               */
/*                                                                          */
/* Returns:     SUCCESS on success.                                         */
/*              FAILURE in case of overflow or of incoherent Profile.       */
/*                                                                          */
/****************************************************************************/

  static Bool  New_Profile( RAS_ARGS TStates  aState )
  {
    if ( !ras.fProfile )
    {
      ras.cProfile  = (PProfile)ras.top;
      ras.fProfile  = ras.cProfile;
      ras.top      += AlignProfileSize;
    }

    if ( ras.top >= ras.maxBuff )
    {
      ras.error = Raster_Err_Overflow;
      return FAILURE;
    }

    switch ( aState )
    {
    case Ascending:
      ras.cProfile->flow = TT_Flow_Up;
      PTRACE7(( "New ascending profile = %lx\n", (long)ras.cProfile ));
      break;

    case Descending:
      ras.cProfile->flow = TT_Flow_Down;
      PTRACE7(( "New descending profile = %lx\n", (long)ras.cProfile ));
      break;

    default:
      PTRACE0(( "Invalid profile direction in Raster:New_Profile !!\n" ));
      ras.error = Raster_Err_Invalid;
      return FAILURE;
    }

    ras.cProfile->start  = 0;
    ras.cProfile->height = 0;
    ras.cProfile->offset = ras.top;
    ras.cProfile->link   = (PProfile)0;
    ras.cProfile->next   = (PProfile)0;

    if ( !ras.gProfile )
      ras.gProfile = ras.cProfile;

    ras.state = aState;
    ras.fresh = TRUE;
    ras.joint = FALSE;

    return SUCCESS;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    End_Profile                                                 */
/*                                                                          */
/* Description: Finalizes the current Profile.                              */
/*                                                                          */
/* Input:       None                                                        */
/*                                                                          */
/* Returns:     SUCCESS on success.                                         */
/*              FAILURE in case of overflow or incoherency.                 */
/*                                                                          */
/****************************************************************************/

  static Bool  End_Profile( RAS_ARG )
  {
    Long      h;
    PProfile  oldProfile;


    h = ras.top - ras.cProfile->offset;

    if ( h < 0 )
    {
      PTRACE0(( "Negative height encountered in End_Profile!\n" ));
      ras.error = Raster_Err_Neg_Height;
      return FAILURE;
    }

    if ( h > 0 )
    {
      PTRACE1(( "Ending profile %lx, start = %ld, height = %ld\n",
                (long)ras.cProfile, ras.cProfile->start, h ));

      oldProfile           = ras.cProfile;
      ras.cProfile->height = h;
      ras.cProfile         = (PProfile)ras.top;

      ras.top             += AlignProfileSize;

      ras.cProfile->height = 0;
      ras.cProfile->offset = ras.top;
      oldProfile->next     = ras.cProfile;
      ras.num_Profs++;
    }

    if ( ras.top >= ras.maxBuff )
    {
      PTRACE1(( "overflow in End_Profile\n" ));
      ras.error = Raster_Err_Overflow;
      return FAILURE;
    }

    ras.joint = FALSE;

    return SUCCESS;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Insert_Y_Turn                                               */
/*                                                                          */
/* Description: Insert a salient into the sorted list placed on top         */
/*              of the render pool                                          */
/*                                                                          */
/* Input:       New y scanline position                                     */
/*                                                                          */
/****************************************************************************/

  static
  Bool Insert_Y_Turn( RAS_ARGS  Int  y )
  {
    PStorage  y_turns;
    Int       y2, n;

    n       = ras.numTurns-1;
    y_turns = ras.sizeBuff - ras.numTurns;

    /* look for first y value that is <= */
    while ( n >= 0 && y < y_turns[n] )
      n--;

    /* if it is <, simply insert it, ignore if == */
    if ( n >= 0 && y > y_turns[n] )
      while ( n >= 0 )
      {
        y2 = y_turns[n];
        y_turns[n] = y;
        y = y2;
        n--;
      }

    if ( n < 0 )
    {
      if (ras.maxBuff <= ras.top)
      {
        ras.error = Raster_Err_Overflow;
        return FAILURE;
      }
      ras.maxBuff--;
      ras.numTurns++;
      ras.sizeBuff[-ras.numTurns] = y;
    }

    return SUCCESS;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Finalize_Profile_Table                                      */
/*                                                                          */
/* Description: Adjusts all links in the Profiles list.                     */
/*                                                                          */
/* Input:       None                                                        */
/*                                                                          */
/* Returns:     None.                                                       */
/*                                                                          */
/****************************************************************************/

  static
  Bool Finalize_Profile_Table( RAS_ARG )
  {
    Int       bottom, top;
    UShort    n;
    PProfile  p;


    n = ras.num_Profs;

    if ( n > 1 )
    {
      p = ras.fProfile;
      while ( n > 0 )
      {
        if ( n > 1 )
          p->link = (PProfile)( p->offset + p->height );
        else
          p->link = NULL;

        switch ( p->flow )
        {
        case TT_Flow_Down:
          bottom     = p->start - p->height+1;
          top        = p->start;
          p->start   = bottom;
          p->offset += p->height-1;
          break;

        case TT_Flow_Up:
        default:
          bottom = p->start;
          top    = p->start + p->height-1;
        }

        if ( Insert_Y_Turn( RAS_VARS  bottom ) ||
             Insert_Y_Turn( RAS_VARS  top+1 )  )
          return FAILURE;

        p = p->link;
        n--;
      }
    }
    else
      ras.fProfile = NULL;

    return SUCCESS;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Split_Bezier                                                */
/*                                                                          */
/* Description: Subdivides one Bezier arc into two joint                    */
/*              sub-arcs in the Bezier stack.                               */
/*                                                                          */
/* Input:       None (subdivided bezier is taken from the top of the        */
/*              stack).                                                     */
/*                                                                          */
/* Returns:     None.                                                       */
/*                                                                          */
/*                                                                          */
/* Note:  This routine is the 'beef' of this component. It is  _the_        */
/*        inner loop that should be optimized to hell to get the            */
/*        best performance.                                                 */
/*                                                                          */
/****************************************************************************/

  static void  Split_Bezier( TPoint*  base )
  {
    Long     a, b;


    base[4].x = base[2].x;
    b = base[1].x;
    a = base[3].x = ( base[2].x + b ) / 2;
    b = base[1].x = ( base[0].x + b ) / 2;
    base[2].x = ( a + b ) / 2;

    base[4].y = base[2].y;
    b = base[1].y;
    a = base[3].y = ( base[2].y + b ) / 2;
    b = base[1].y = ( base[0].y + b ) / 2;
    base[2].y = ( a + b ) / 2;

    /* hand optimized.  gcc doesn't seem too good at common expression */
    /* substitution and instruction scheduling ;-)                     */
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Push_Bezier                                                 */
/*                                                                          */
/* Description: Clears the Bezier stack and pushes a new arc on top of it.  */
/*                                                                          */
/* Input:       x1,y1 x2,y2 x3,y3  new Bezier arc                           */
/*                                                                          */
/* Returns:     None.                                                       */
/*                                                                          */
/****************************************************************************/

  static void  Push_Bezier( RAS_ARGS Long  x1, Long  y1,
                                     Long  x2, Long  y2,
                                     Long  x3, Long  y3 )
  {
    ras.arc      = ras.arcs;
    ras.arc[2].x = x1; ras.arc[2].y = y1;
    ras.arc[1].x = x2; ras.arc[1].y = y2;
    ras.arc[0].x = x3; ras.arc[0].y = y3;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Line_Up                                                     */
/*                                                                          */
/* Description: Computes the x-coordinates of an ascending line segment     */
/*              and stores them in the render pool.                         */
/*                                                                          */
/* Input:       x1,y1,x2,y2  Segment start (x1,y1) and end (x2,y2) points   */
/*                                                                          */
/* Returns:     SUCCESS on success.                                         */
/*              FAILURE on Render Pool overflow.                            */
/*                                                                          */
/****************************************************************************/

  static Bool  Line_Up( RAS_ARGS Long  x1, Long  y1,
                                 Long  x2, Long  y2,
                                 Long  miny, Long  maxy )
  {
    Long  Dx, Dy;
    Int   e1, e2, f1, f2, size;     /* XXX: is `Short' sufficient? */
    Long  Ix, Rx, Ax;

    PStorage  top;


    Dx = x2 - x1;
    Dy = y2 - y1;

    if ( Dy <= 0 || y2 < miny || y1 > maxy )
      return SUCCESS;

    if ( y1 < miny )
    {
      /* Take care : miny-y1 can be a very large value, we use     */
      /*             a slow MulDiv function to avoid clipping bugs */
      x1 += SMulDiv( Dx, miny - y1, Dy );
      e1  = TRUNC( miny );
      f1  = 0;
    }
    else
    {
      e1 = TRUNC( y1 );
      f1 = FRAC( y1 );
    }

    if ( y2 > maxy )
    {
      /* x2 += FMulDiv( Dx, maxy - y2, Dy );  UNNECESSARY */
      e2  = TRUNC( maxy );
      f2  = 0;
    }
    else
    {
      e2 = TRUNC( y2 );
      f2 = FRAC( y2 );
    }

    if ( f1 > 0 )
    {
      if ( e1 == e2 ) return SUCCESS;
      else
      {
        x1 += FMulDiv( Dx, ras.precision - f1, Dy );
        e1 += 1;
      }
    }
    else
      if ( ras.joint )
      {
        ras.top--;
        ras.joint = FALSE;
      }

    ras.joint = ( f2 == 0 );

    if ( ras.fresh )
    {
      ras.cProfile->start = e1;
      ras.fresh           = FALSE;
    }

    size = e2 - e1 + 1;
    if ( ras.top + size >= ras.maxBuff )
    {
      ras.error = Raster_Err_Overflow;
      return FAILURE;
    }

    if ( Dx > 0 )
    {
      Ix = (ras.precision*Dx) / Dy;
      Rx = (ras.precision*Dx) % Dy;
      Dx = 1;
    }
    else
    {
      Ix = -( (ras.precision*-Dx) / Dy );
      Rx =    (ras.precision*-Dx) % Dy;
      Dx = -1;
    }

    Ax  = -Dy;
    top = ras.top;

    while ( size > 0 )
    {
      *top++ = x1;

      DEBUG_PSET;

      x1 += Ix;
      Ax += Rx;
      if ( Ax >= 0 )
      {
        Ax -= Dy;
        x1 += Dx;
      }
      size--;
    }

    ras.top = top;
    return SUCCESS;
  }


  static Bool  Line_Down( RAS_ARGS Long  x1, Long  y1,
                                   Long  x2, Long  y2,
                                   Long  miny, Long  maxy )
  {
    Bool result, fresh;