micro(A) demo : Santa Cutter

[bplus]

Yeah vince had the QB64 version of that with the star last year at least:

Code: (Select All)

Dim Shared pi, sw, sh, d, z0, p, q
pi = 4 * Atn(1)
d = 700
z0 = 2500

sw = 800
sh = 600

Dim As Double a, b, x, y, z, xx, yy, zz
Screen _NewImage(sw, sh, 32)
Do
    b = b + 0.03
    Cls
    'tree
    For a = 0 To 20 * 2 * pi Step 0.1
        x = 5 * a * Cos(a)
        y = -a * 10
        z = 5 * a * Sin(a)

        yy = (y + 350) * Cos(b) - z * Sin(b)
        zz = (y + 350) * Sin(b) + z * Cos(b)
        y = yy - 350
        z = zz

        xx = x * Cos(b) - z * Sin(b)
        zz = x * Sin(b) + z * Cos(b)
        x = xx
        z = zz

        xx = x * Cos(b) - (y + 350) * Sin(b)
        yy = x * Sin(b) + (y + 350) * Cos(b)
        x = xx
        y = yy - 350

        proj x, y, z

        Circle (p, q), 1, _RGB(0, 155, 0)
    Next


    'star a pixel at a time
    For a = 0 To 6 * pi Step 0.1
        rr = 100
        r = 60
        x = (rr - r) * Cos(a + pi / 4) + 70 * Cos(((rr - r) / r) * a)
        y = 50 + (rr - r) * Sin(a + pi / 4) - 70 * Sin(((rr - r) / r) * a)
        z = 0

        yy = (y + 350) * Cos(b) - z * Sin(b)
        zz = (y + 350) * Sin(b) + z * Cos(b)
        y = yy - 350
        z = zz

        xx = x * Cos(b) - z * Sin(b)
        zz = x * Sin(b) + z * Cos(b)
        x = xx
        z = zz

        xx = x * Cos(b) - (y + 350) * Sin(b)
        yy = x * Sin(b) + (y + 350) * Cos(b)
        x = xx
        y = yy - 350

        proj x, y, z

        Circle (p, q), 1, _RGB(255, 255, 0)
    Next
    _Display
    _Limit 50
Loop

Sub proj (x, y, z)
    p = sw / 2 + x * d / (z + z0)
    q = sh / 2 - (100 + y) * d / (z + z0) - 150
End Sub