help moving a sprite in a ellipse

[TerryRitchie]

Here is the simplest example I could come up with. This code creates 360 points around a circle. By varying XSIZE and YSIZE you can squash (YSIZE) or elongate (XSIZE) the ellipse.

Replace the CIRCLE command with your sprite's _PUTIMAGE statement.

Code: (Select All)

CONST RADIUS = 200



CONST XSIZE = 1

CONST YSIZE = .5





DIM x(359) AS SINGLE

DIM y(359) AS SINGLE



FOR i = 0 TO 359

    x(i) = SIN(_D2R(i)) * RADIUS * XSIZE

    y(i) = -COS(_D2R(i)) * RADIUS * YSIZE

NEXT i



SCREEN _NEWIMAGE(640, 480, 32)

CLS



i = 0

DO



    _LIMIT 60

    CLS

    CIRCLE (319 + x(i), 239 + y(i)), 20



    i = i + 1

    IF i = 360 THEN i = 0

    _DISPLAY

LOOP UNTIL _KEYDOWN(27)