168 procedure ColorizeLandFast(Surface: PSDL_Surface);

   169 var ltsurf: PSDL_Surface;

   170     x, y, ltw, lth, c, modc, lastfull: LongInt;

   171     srcp, dstp: Pointer;

   172 begin

   173     ltsurf:= LoadDataImage(ptCurrTheme, 'LandTex', ifCritical or ifIgnoreCaps);

   174     ltw:= ltsurf^.w;

   175     lth:= ltsurf^.h;

   176 

   177     // pointer to ltturf pixels. will be moved from line to line

   178     srcp:= ltsurf^.pixels;

   179     // pointer to Surface pixels. will be moved forward with every move()

   180     dstp:= Surface^.pixels;

   181 

   182     // amount of pixels to write per move()

   183     c:= ltsurf^.pitch;

   184     // amount of pixels to write for line's remainer move()

   185     modc:= Surface^.pitch mod c;

   186 

   187     SDL_LockSurface(Surface);

   188     SDL_LockSurface(ltsurf);

   189 

   190     y:= 0;

   191     // last x where a full line from src may be written to

   192     lastfull:= Surface^.w - ltw;

   193     // only copy in one row of landtex. do copies within Surface after

   194     while (y < lth) and (y < Surface^.h) do

   195         begin

   196         x:= 0;

   197         // fill dst line with src lines

   198         while x <= lastfull do

   199             begin

   200             move(srcp^, dstp^, c);

   201             inc(dstp, c);

   202                 inc(x, ltw);

   203             end;

   204 

   205         // if it didn't fit perfectly, copy remainder

   206         if modc > 0 then

   207             begin

   208             move(srcp^, dstp^, modc);

   209             inc(dstp, modc);

   210             end;

   211 

   212         // move to next line in src surface

   213         inc(srcp, ltsurf^.pitch);

   214         inc(y);

   215         end;

   216 

   217     // we don't need ltsurf anymore -> cleanup

   218     srcp:= nil;

   219     SDL_UnlockSurface(ltsurf);

   220     SDL_FreeSurface(ltsurf);

   221 

   222     // from now on only copy pixels within Surface

   223 

   224     // start reading from position 0, but continue writing at dstp

   225     srcp:= Surface^.pixels;

   226     // copy all the already written lines at once for that get number of written bytes so far

   227     c:= dstp - srcp; // effectively same as c:= lth * Surface^.pitch;

   228     // also figure out the remainder again

   229     modc:= (Surface^.h mod lth) * Surface^.pitch; // effectivle same as modc:= (Surface^.pitch * Surface^.h) mod c;

   230 

   231     // last y where a full copy may be written to

   232     lastfull:= Surface^.h - lth;

   233 

   234     // copy filled area down

   235     while y <= lastfull do

   236         begin

   237         move(srcp^, dstp^, c);

   238         inc(srcp, c);

   239         inc(dstp, c);

   240         inc(y, lth);

   241         end;

   242 

   243     // if it didn't fit perfectly, copy remainder

   244     if modc > 0 then

   245         begin

   246         move(srcp^, dstp^, modc);

   247         end;

   248 

   249     SDL_UnlockSurface(Surface);

   250 

   251     // freed in freeModule() below

   252     LandBackSurface:= LoadDataImage(ptCurrTheme, 'LandBackTex', ifIgnoreCaps or ifTransparent);

   253     if (LandBackSurface <> nil) and GrayScale then Surface2GrayScale(LandBackSurface);

   254 end;

   255