Rotating Globe

[SMcNeill]

Code: (Select All)

_Title "Rotating Sphere in QB64PE"
Screen _NewImage(800, 600, 32)
Dim Shared sphere(360, 360) As _Unsigned Long
Dim Shared rotationX, rotationY As Single

' Initialize the sphere
For phi = 0 To 359
    For theta = 0 To 359
        x = Cos(_D2R(phi)) * Sin(_D2R(theta))
        y = Sin(_D2R(phi)) * Sin(_D2R(theta))
        z = Cos(_D2R(theta))
        sphere(phi, theta) = _RGB32(Cos(_D2R(phi)) * 127 + 128, Sin(_D2R(phi)) * 127 + 128, z * 127 + 128)
    Next
Next

' Main loop
Do
    If _KeyDown(18432) Then rotationX = rotationX - 5
    If _KeyDown(20480) Then rotationX = rotationX + 5
    If _KeyDown(19200) Then rotationY = rotationY - 5
    If _KeyDown(19712) Then rotationY = rotationY + 5
    Cls , 0
    _PrintString (0, 0), "Rotating Rainbow Sphere"
    _PrintString (0, 16), "Use arrow keys to rotate"

    ' Draw the sphere
    For phi = 0 To 359 Step .25
        For theta = 0 To 359 Step .25
            x = Cos(_D2R(phi)) * Sin(_D2R(theta))
            y = Sin(_D2R(phi)) * Sin(_D2R(theta))
            z = Cos(_D2R(theta))

            ' Rotate around X axis
            y1 = y * Cos(_D2R(rotationX)) - z * Sin(_D2R(rotationX))
            z1 = y * Sin(_D2R(rotationX)) + z * Cos(_D2R(rotationX))
            y = y1
            z = z1

            ' Rotate around Y axis
            x1 = x * Cos(_D2R(rotationY)) + z * Sin(_D2R(rotationY))
            z1 = -x * Sin(_D2R(rotationY)) + z * Cos(_D2R(rotationY))
            x = x1
            z = z1

            ' Project to 2D
            screenX = 400 + x * 200
            screenY = 300 - y * 200
            PSet (screenX, screenY), sphere(phi, theta)
        Next
    Next

    _Display
    _Limit 60
Loop Until _KeyDown(27)

Now I just need to sort out how to read a 2d map and convert it up to 3d coordinates, and I'll be able to rotate the earth for a program.

Anyone want to take on that part of the fun?