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QuadBlitter_scanning.inl

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#define SETUP_SECOND_UV
#ifdef USE_UV
   #undef SETUP_SECOND_UV 
   #define SETUP_SECOND_UV u0=u0b;v0=v0b;u1=u1b;v1=v1b;
#endif

#define SET_UV(uv0u,uv0v,uv1u,uv1v) u0=uv0u;v0=uv0v;u1=uv1u;v1=uv1v;


#define SET_UV_TWO(uv0u,uv0v,uv1u,uv1v,uv0ub,uv0vb,uv1ub,uv1vb) u0=uv0u;v0=uv0v;u1=uv1u;v1=uv1v; u0b=uv0ub;v0b=uv0vb;u1b=uv1ub;v1b=uv1vb;

#define INT_SETUP_UV
#ifdef USE_UV
   #undef INT_SETUP_UV
   #define INT_SETUP_UV \
      int stepU=(u1-u0)/(DeltaY);\
      int stepV=(v1-v0)/(DeltaY);\

#endif

#define INT_UPDATE_UV
#ifdef USE_UV
   #undef INT_UPDATE_UV
   #define INT_UPDATE_UV \
      u0+=stepU;\
      v0+=stepV;\

#endif

#define INT_ASSIGN_UV
#ifdef USE_UV
   #undef INT_ASSIGN_UV
   #define INT_ASSIGN_UV \
      (*tempBuffer).u=u0; \
      (*tempBuffer).v=v0; \

#endif

#define INTERPOLATE_EDGE_XMAJOR(X0,Y0,DeltaX,DeltaY,XDirection)\
   {\
   INT_SETUP_UV\
   int XMajorAdvanceAmt=(DeltaX/DeltaY)*XDirection;\
   int ErrorTermAdvance=DeltaX%DeltaY;\
   int ErrorTerm=0;\
   int height=DeltaY;\
   if (XDirection<0)\
      {\
      ErrorTerm = -DeltaY + 1;   \
      }\
   (*tempBuffer).x=(unsigned short)X0; \
   INT_ASSIGN_UV\
   while ( DeltaY-- )\
      {\
      INT_UPDATE_UV\
      X0 += XMajorAdvanceAmt;    \
      ErrorTerm += ErrorTermAdvance;\
      if (ErrorTerm > 0) \
         {\
         X0 += XDirection; \
         ErrorTerm -= height; \
         }\
      tempBuffer+=2;\
      (*tempBuffer).x=(unsigned short)X0; \
      INT_ASSIGN_UV\
      }\
   }\



#define INTERPOLATE_EDGE_YMAJOR(X0,Y0,DeltaX,DeltaY,XDirection)\
   {\
   INT_SETUP_UV\
   /* Set up initial error term and values used inside drawing loop */\
   int DeltaXx2 = DeltaX + DeltaX;\
   int DeltaXx2MinusDeltaYx2 = DeltaXx2 - ( DeltaY + DeltaY );\
   int ErrorTerm = DeltaXx2 - DeltaY;\
   (*tempBuffer).x=(unsigned short)X0; \
   INT_ASSIGN_UV\
   while ( DeltaY-- ) \
      {\
      INT_UPDATE_UV\
      /* See if it's time to advance the X coordinate */\
      if ( ErrorTerm >= 0 ) \
         {\
         /* Advance the X coordinate & adjust the error term   back down */\
         X0 += XDirection;\
         ErrorTerm += DeltaXx2MinusDeltaYx2;\
         } \
      else \
         {\
         /* Add to the error term */\
         ErrorTerm += DeltaXx2;\
         }\
      tempBuffer+=2;\
      (*tempBuffer).x=(unsigned short)X0; \
      INT_ASSIGN_UV\
      }\
   }\



#define EGDE_INTERPOLATION(XP0,YP0,XP1,YP1) \
   {\
   int X0=XP0;\
   int Y0=YP0;\
   int X1=XP1;\
   int Y1=YP1;\
   /* calculate the length of the line in each coordinate */\
   int DeltaX=X1-X0;    \
   int DeltaY=Y1-Y0;\
   /* Handle as four separate cases, for the four octants in which Y1 is greater than Y0 */\
   if (DeltaX>0 ) \
      {\
      int XDirection=1;\
      if (DeltaX>DeltaY)\
         {\
         INTERPOLATE_EDGE_XMAJOR(X0, Y0, DeltaX, DeltaY, 1);\
         } \
      else \
         {\
         INTERPOLATE_EDGE_YMAJOR(X0, Y0, DeltaX, DeltaY, 1);\
         }\
      } \
   else \
      {\
      int XDirection=-1;\
      DeltaX=-DeltaX; /* absolute value of DeltaX */\
      if (DeltaX>DeltaY ) \
         {\
         INTERPOLATE_EDGE_XMAJOR(X0, Y0, DeltaX, DeltaY, -1);\
         } \
      else \
         {\
         INTERPOLATE_EDGE_YMAJOR(X0, Y0, DeltaX, DeltaY, -1);\
         }\
      }\
   }\


#define ScanEdge(x1, y1, x2, y2, edgeBufferPtr) \
   { \
   int tempX1=x1;\
   int tempY1=y1;\
   int tempX2=x2;\
   int tempY2=y2;\
   EDGE_TYPE* tempBuffer=edgeBufferPtr;\
   EGDE_INTERPOLATION(tempX1,tempY1,tempX2,tempY2);   \
   }\


#define ScanTwoEdges(x1a, y1a, x2a, y2a, x1b, y1b, x2b, y2b, edgeBufferPtr) \
   { \
   int tempX1a=x1a;\
   int tempY1a=y1a;\
   int tempX2a=x2a;\
   int tempY2a=y2a;\
   int tempX1b=x1b;\
   int tempY1b=y1b;\
   int tempX2b=x2b;\
   int tempY2b=y2b;\
   EDGE_TYPE* tempBuffer=edgeBufferPtr;\
   EGDE_INTERPOLATION(tempX1a,tempY1a,tempX2a,tempY2a);  \
   SETUP_SECOND_UV\
   EGDE_INTERPOLATION(tempX1b,tempY1b,tempX2b,tempY2b);  \
   }\


//*** MAIN CODE ***


   int p0x=targetX1;
   int p0y=targetY1;
   int p1x=targetX2;
   int p1y=targetY2;
   int p2x=targetX3;
   int p2y=targetY3;
   int p3x=targetX4;
   int p3y=targetY4;

   #ifdef USE_UV
      int s0x=sourceX1<<16;
      int s0y=sourceY1<<16;
      int s1x=sourceX2<<16;
      int s1y=sourceY2<<16;
      int s2x=sourceX3<<16;
      int s2y=sourceY3<<16;
      int s3x=sourceX4<<16;
      int s3y=sourceY4<<16;
   #endif

   // order by y
   if (p1y<p0y)
      {
      Swap(p1x,p0x);
      Swap(p1y,p0y);
      #ifdef USE_UV
         Swap(s1x,s0x);
         Swap(s1y,s0y);
      #endif
      }
   if (p2y<p0y)
      {
      Swap(p2x,p0x);
      Swap(p2y,p0y);
      #ifdef USE_UV
         Swap(s2x,s0x);
         Swap(s2y,s0y);
      #endif
      }
   if (p3y<p0y)
      {
      Swap(p3x,p0x);
      Swap(p3y,p0y);
      #ifdef USE_UV
         Swap(s3x,s0x);
         Swap(s3y,s0y);
      #endif
      }
   if (p2y<p1y)
      {
      Swap(p2x,p1x);
      Swap(p2y,p1y);
      #ifdef USE_UV
         Swap(s2x,s1x);
         Swap(s2y,s1y);
      #endif
      }
   if (p3y<p1y)
      {
      Swap(p3x,p1x);
      Swap(p3y,p1y);
      #ifdef USE_UV
         Swap(s3x,s1x);
         Swap(s3y,s1y);
      #endif
      }
   if (p3y<p2y)
      {
      Swap(p3x,p2x);
      Swap(p3y,p2y);
      #ifdef USE_UV
         Swap(s3x,s2x);
         Swap(s3y,s2y);
      #endif
      }

   Assert(p0y<=p1y && p1y<=p2y && p2y<=p3y,"Sort order error");

   // Allocate or reallocate edge buffer if needed
   edgeBuffer_.SetMinSize(sizeof(EDGE_TYPE)*2*(p3y-p0y+1));
   EDGE_TYPE* edgeBuffer=static_cast<EDGE_TYPE*>(edgeBuffer_.buffer_);

   #ifdef USE_UV
      int u0=0;
      int v0=0;
      int u1=0;
      int v1=0;
      int u0b=0;
      int v0b=0;
      int u1b=0;
      int v1b=0;
   #endif

   // Flat top and bottom?
   if (p0y==p1y && p2y==p3y)
      {
      if (p0x<p1x)
         {
         #ifdef USE_UV
            SET_UV(s0x,s0y,s3x,s3y);
         #endif
         ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer);  

         #ifdef USE_UV
            SET_UV(s1x,s1y,s2x,s2y);
         #endif
         ScanEdge(p1x,p1y,p2x,p2y,edgeBuffer+1);   
         }
      else
         {
         #ifdef USE_UV
            SET_UV(s1x,s1y,s2x,s2y);
         #endif
         ScanEdge(p1x,p1y,p2x,p2y,edgeBuffer);  

         #ifdef USE_UV
            SET_UV(s0x,s0y,s3x,s3y);
         #endif
         ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer+1);   
         }
      }
   
   // Flat top?
   else if (p0y==p1y)
      {
      if (p0x<p1x)
         {
         if (p2x<p3x)
            {
            //0 to 2, 2 to 3
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s2x,s2y,s2x,s2y,s3x,s3y);
            #endif
            ScanTwoEdges(p0x,p0y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer);

            //1 to 3
            #ifdef USE_UV
               SET_UV(s1x,s1y,s3x,s3y);
            #endif
            ScanEdge(p1x,p1y,p3x,p3y,edgeBuffer+1);               
            }
         else
            {
            //0 to 3
            #ifdef USE_UV
               SET_UV(s0x,s0y,s3x,s3y);
            #endif
            ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer);              

            //1 to 2, 2 to 3
            #ifdef USE_UV
               SET_UV_TWO(s1x,s1y,s2x,s2y,s2x,s2y,s3x,s3y);
            #endif
            ScanTwoEdges(p1x,p1y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer+1);
            }
         }
      else
         {
         if (p2x<p3x)
            {
            // 1 to 2, 2 to 3
            #ifdef USE_UV
               SET_UV_TWO(s1x,s1y,s2x,s2y,s2x,s2y,s3x,s3y);
            #endif
            ScanTwoEdges(p1x,p1y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer);

            //0 to 3
            #ifdef USE_UV
               SET_UV(s0x,s0y,s3x,s3y);
            #endif
            ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer+1);               
            }
         else
            {
            // 1 to 3
            #ifdef USE_UV
               SET_UV(s1x,s1y,s3x,s3y);
            #endif
            ScanEdge(p1x,p1y,p3x,p3y,edgeBuffer);              

            // 0 to 2, 2 to 3
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s2x,s2y,s2x,s2y,s3x,s3y);
            #endif
            ScanTwoEdges(p0x,p0y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer+1);
            }
         }
      }
   
   // Flat bottom?
   else if (p2y==p3y)
      {
      if (p3x<p2x)
         {
         if (p1x<p0x)
            {
            // 0 to 1, 1 to 3
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s3x,s3y);
            #endif
            ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p3x,p3y,edgeBuffer);

            // 0 to 2
            #ifdef USE_UV
               SET_UV(s0x,s0y,s2x,s2y);
            #endif
            ScanEdge(p0x,p0y,p2x,p2y,edgeBuffer+1);               
            }
         else
            {
            // 0 to 3
            #ifdef USE_UV
               SET_UV(s0x,s0y,s3x,s3y);
            #endif
            ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer);              

            // 0 to 1, 1 to 2
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s2x,s2y);
            #endif
            ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p2x,p2y,edgeBuffer+1);
            }
         }
      else
         {
         if (p0x<p1x)
            {
            // 0 to 2
            #ifdef USE_UV
               SET_UV(s0x,s0y,s2x,s2y);
            #endif
            ScanEdge(p0x,p0y,p2x,p2y,edgeBuffer);              

            // 0  to 1, 1 to 3
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s3x,s3y);
            #endif
            ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p3x,p3y,edgeBuffer+1);
            }
         else
            {
            // 0 to 1, 1 to 2
            #ifdef USE_UV
               SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s2x,s2y);
            #endif
            ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p2x,p2y,edgeBuffer);

            // 0 to 3
            #ifdef USE_UV
               SET_UV(s0x,s0y,s3x,s3y);
            #endif
            ScanEdge(p0x,p0y,p3x,p3y,edgeBuffer+1);               
            }

         }
      }

   // Generic case
   else
      {
      if (p1x<p2x)
         {
         #ifdef USE_UV
            SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s3x,s3y);
         #endif
         ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p3x,p3y,edgeBuffer);

         #ifdef USE_UV
            SET_UV_TWO(s0x,s0y,s2x,s2y,s2x,s2y,s3x,s3y);
         #endif
         ScanTwoEdges(p0x,p0y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer+1);
         }
      else
         {
         #ifdef USE_UV
            SET_UV_TWO(s0x,s0y,s2x,s2y,s2x,s2y,s3x,s3y);
         #endif
         ScanTwoEdges(p0x,p0y,p2x,p2y,p2x,p2y,p3x,p3y,edgeBuffer);

         #ifdef USE_UV
            SET_UV_TWO(s0x,s0y,s1x,s1y,s1x,s1y,s3x,s3y);
         #endif
         ScanTwoEdges(p0x,p0y,p1x,p1y,p1x,p1y,p3x,p3y,edgeBuffer+1);
         }
      }

#undef INTERPOLATE_EDGE_XMAJOR
#undef INTERPOLATE_EDGE_YMAJOR
#undef EGDE_INTERPOLATION
#undef ScanEdge
#undef ScanTwoEdges
#undef SETUP_SECOND_UV
#undef SET_UV
#undef SET_UV_TWO
#undef INT_SETUP_UV
#undef INT_UPDATE_UV
#undef INT_ASSIGN_UV

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