COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	BEGIN "POLYTS"
C00004 ENDMK
C⊗;
BEGIN "POLYTS"
INTEGER L;
REQUIRE "VIXHDR.SAI[VIS,HPM]" SOURCE_FILE;
REQUIRE "PICGRA.SAI[VIS,HPM]" SOURCE_FILE;
   BEGIN
   REAL SS,CC;
   INTEGER ARRAY PIC[0:PIXDIM(481,512,9)];
   REAL ARRAY PX,PY[1:4];

   SS←SIN(0.1); CC←COS(0.1);
   MAKPIX(481,512,9,PIC[0]);
   PSCREEN(0,0,1,1,PIC[0]);
   PX[1]←.3; PY[1]←.3;
   PX[2]←.45; PY[2]←.1;
   PX[3]←.7; PY[3]←.4;
   PX[4]←.5; PY[4]←.7;
   WHILE TRUE DO
      BEGIN
      WIPE(PIC[0],0);
      FOR L←1,2,3,4 DO
         BEGIN
         REAL XT,YT;
         XT←PX[L]-.5; YT←PY[L]-.5;
         PX[L]←XT*CC-YT*SS+.5;
         PY[L]←YT*CC+XT*SS+.5;
         END;
      CPOLY(4,PX[1],PY[1],1);
      GRAY(PIC[0]); MAPGRY(1,PIC[BYBI]);
      FOR L ← 0 STEP 1 UNTIL PIC[BYBI]-1 DO IF SYNMAP(L)>0 THEN
	 BEGIN
	 DDINIT; VIDONE(PIC[0], 1 LSH (PIC[BYBI]-1-L));
         DPYUP(SYNMAP(L));
	 END;
      END;
   END;

END;