- Now this function uses the symmetric property of modolo operator.
- It works with a negative angle
Code: Select all
; ************
; fast cosine
; fast sine
; ************
#_COSINE_MAX_INDEX=$100000 ; <----------- symmetric modulo is enabled by the power of 2
#_MATH_DEGREE_TO_INDEX=#_COSINE_MAX_INDEX/360.0
#_MATH_DEGREE_TO_RADIAN=#PI*2.0/360.0
Global Dim _SIN.f(#_COSINE_MAX_INDEX)
Global Dim _COS.f(#_COSINE_MAX_INDEX)
For i=0 To #_COSINE_MAX_INDEX
_COS(i)=Cos(i*2.0*#PI/#_COSINE_MAX_INDEX)
_SIN(i)=Sin(i*2.0*#PI/#_COSINE_MAX_INDEX)
Next
Macro FastCos(a) : _COS(Int(a*#_MATH_DEGREE_TO_INDEX)%#_COSINE_MAX_INDEX) : EndMacro
Macro FastSin(a) : _SIN(Int(a*#_MATH_DEGREE_TO_INDEX)%#_COSINE_MAX_INDEX) : EndMacro
; ************
; TEST
; ************
#TEST_MAX_ANGLE=11000000;9900000
Define.f x, y
t=ElapsedMilliseconds()
For a=0 To #TEST_MAX_ANGLE Step 7
x=Cos(a*#_MATH_DEGREE_TO_RADIAN)
y=Sin(a*#_MATH_DEGREE_TO_RADIAN)
Next
t1=ElapsedMilliseconds()-t
t=ElapsedMilliseconds()
For a=0 To #TEST_MAX_ANGLE Step 7
x=FastCos(a)
y=FastSin(a)
Next
t2=ElapsedMilliseconds()-t
result.s="NORMAL t="+Str(t1)
result+#CRLF$+"FAST t="+Str(t2)+" --> "+Str(100*t2/t1)+"%"
V=-90
result+#CRLF$+"Sin("+Str(V)+")="+StrF(FastSin(V))+" ~ "+StrF(Sin(V*#_MATH_DEGREE_TO_RADIAN))
V=90
result+#CRLF$+"Sin("+Str(V)+")="+StrF(FastSin(V))+" ~ "+StrF(Sin(V*#_MATH_DEGREE_TO_RADIAN))
V=180
result+#CRLF$+"Cos("+Str(V)+")="+StrF(FastCos(V))+" ~ "+StrF(Cos(V*#_MATH_DEGREE_TO_RADIAN))
V=111+360*10
result+#CRLF$+"Sin("+Str(V)+")="+StrF(FastSin(V))+" ~ "+StrF(Sin(V*#_MATH_DEGREE_TO_RADIAN))
OpenWindow(0, 0, 0, 300, 300, "FAST COS FAST SIN", #PB_Window_SystemMenu | #PB_Window_ScreenCentered)
EditorGadget(1, 5, 5, 290, 290)
SetGadgetText(1, result)
Repeat : Until WaitWindowEvent()=#PB_Event_CloseWindow
