Another small filled circe sub (not as fast as fcirc)

[SMcNeill]

Yes, I recall how Bill didn't think using SQR could possibly work, until I did exactly that. Mostly thanks to _INTEGER64, it worked.

That reminds me....

Code: (Select All)

Sub FC3 (cx, cy, r, clr&)

    Line (cx - r, cy)-(cx + r, cy), clr&, BF

    y = 1

    r2 = r * r ' Dav mod

    While y <= r

        y2 = y * y

        If y2 < r2 Then

            x = Int(Sqr(r2 - y2))

            Line (cx - x, cy + y)-(cx + x, cy + y), clr&, BF

            Line (cx - x, cy - y)-(cx + x, cy - y), clr&, BF

        End If

        y = y + 1

    Wend

End Sub

Could be modified to...

Code: (Select All)

Sub FC3 (cx, cy, r, clr&)

    Dim x as Integer

    Line (cx - r, cy)-(cx + r, cy), clr&, BF

    r2 = r * r ' Dav mod

    Do Until y > r

        y = y + 1 

        y2 = y * y

        If y2 < r2 Then

            x = Sqr(r2 - y2)

            Line (cx - x, cy + y)-(cx + x, cy + y), clr&, BF

            Line (cx - x, cy - y)-(cx + x, cy - y), clr&, BF

        End If

    Loop

End Sub

Pete

My thinking was to make use of something like this:

Code: (Select All)

Sub PreCalcX
    For r = 0 To 500 'circles with a radius from 0 to 500
        r2 = r * r
        For y = 0 To r
            y2 = y * y
            x = Int(Sqr(r2 - y2))
            CircleXPos(r, y) = x
        Next
    Next
End Sub

Precalculate all that math, and get rid of it completely.  Just one quick lookup for that value rather than multiplying and all that.

It would seem to me that *this* should be much faster than everything else is:

Code: (Select All)

Sub StevePreCalcCircle (cx, cy, r, clr&)
    $Checking:Off
    For y = 0 To r
        x = CircleXPos(r, y)
        Line (cx - x, cy - y)-(cx + x, cy - y), clr&, BF
        Line (cx - x, cy + y)-(cx + x, cy + y), clr&, BF
    Next
    $Checking:On
End Sub

Just look up that one value from a precalculated list.   And yet... almost impossibly... it's often not the fastest method we have available, when resting those speeds all side by side!

Are our arrays that slow?
Is the timer routine screwing up somewhere?
WTF is going on to give us the figures that we're getting??

I have no clue.  I just found the results upper astonishing.