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Might make SBS readonly: thread

Fast ellipse drawing

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MZ952Created: 
OPTION STRICT
OPTION DEFINT
DEF ELLIPSE ORGX,ORGY,RDSX,RDSY,COL
 DIM X,Y,PX,PY=-RDSY
 DIM TST#,PTST#
 DIM RDSX_SQRD=RDSX*RDSX
 DIM RDSY_SQRD=RDSY*RDSY
 DIM STEP=2
 FOR Y=-RDSY TO STEP STEP STEP
  FOR X=-RDSX TO STEP STEP STEP
   PTST#=TST#
   TST#=X*X/RDSX_SQRD+Y*Y/RDSY_SQRD
   IF PTST#>1 && TST#<=1 THEN
    GLINE X+ORGX,Y+ORGY,PX+ORGX,PY+ORGY,COL
    GLINE -X+ORGX,Y+ORGY,-PX+ORGX,PY+ORGY,COL
    GLINE X+ORGX,-Y+ORGY,PX+ORGX,-PY+ORGY,COL
    GLINE -X+ORGX,-Y+ORGY,-PX+ORGX,-PY+ORGY,COL
    PX=X:PY=Y
    X=-RDSX/(Y+RDSY+3)
    Y=Y+STEP
   ENDIF
  NEXT X
 NEXT Y
END
ELLIPSE OriginX, OriginY, RadiusX, RadiusY, Color Code Got an idea for (probably) fast filled ellipse drawing too. Increment STEP to draw faster. Every increment just about cuts the drawing time down by three. STEP=2 is best imo.
ResourcesCode Snippets
MZ952#1
I'm actually very surprised how difficult it was to create an ellipse function that draws faster than the typical approach with the loop over radians and calling SIN and COS. I thought those functions were slow, but they're actually not. I guess they probably do nothing more than call values from an internal table.
chicken#2
heh heh ORGY
answer#3
Replying to:chicken
heh heh ORGY
stop dat dude