Rotate and Scale Mesh Shape

[King Mocker]

I found and converted a program to display a shape from several points from a BBC Micro Advanced Graphics book from 1983.
The program only displayed it and ended.
Once I had replicated that I decided to make it a bit fancier and added some extra bits to it.

Code: (Select All)

Option _Explicit
Screen _NewImage(800, 600, 32)

Dim As Integer x(30), y(30)
Dim As Integer N, XC, YC, size, i, j
Dim As Integer dx, dy, scale, maxsize, minsize, maxdxy, shape
Dim As Integer framecounter
Dim As Single alpha, spinspeed, adif
Dim As Long shapecolor
'##################################
' Setup some default values
'##################################
XC = 300 + Int(Rnd * 200): YC = 200 + Int(Rnd * 200)
N = 10
alpha = 0
spinspeed = 0.005
size = 150: scale = 10: minsize = 50: maxsize = 200
dx = 5 + Int(Rnd * 5) + 1: dy = 5 + Int(Rnd * 5) + 1: maxdxy = 40
shape = 1: shapecolor = _RGB32(240, 240, 240)
framecounter = 0
'#####################################################
'## Main loop
'#####################################################
Do
    '##################################################################################################################
    '## Calculate a new LIMIT based on the size of the shape,
    '## smaller shape faster speed, larger shape slower speed
    '##################################################################################################################
    _Limit Int((220 - size) * 0.15 + 10)
    Cls , _RGB32(0, 0, 0)
    Locate 1, 1: Print "Left/Right: Dec/Inc Spin Speed.     Down/Up: Dec/Inc. size         -/+:   Dec/Inc # of Points"
    Locate 2, 1: Print "Q/W       : Dec/Inc X direction     D/E    : Dec/Inc Y direction   Space: Change Shape"

    '##################################
    '## Generate new points for the shape
    '##################################
    adif = (2 * _Pi / N) + spinspeed
    For i = 1 To N
        x(i) = Cos(alpha) * size + XC: y(i) = Sin(alpha) * size + YC
        alpha = alpha + adif
    Next i

    '##################
    '## Draw the shape
    '##################
    For i = 1 To N - 1
        For j = i + 1 To N
            If shape = 1 Then
                Line (x(i), y(i))-(x(j), y(j)), shapecolor '           Draws only lines
            Else
                Line (x(i), y(i))-(x(j), y(j)), shapecolor, B '        Draws Boxes
            End If
        Next j
    Next i
    _Display
    '##############################
    ' Get new shape screen position
    '##############################
    XC = XC + dx
    YC = YC + dy

    '##########################################################################################################################################
    '## Process Key presses
    '##########################################################################################################################################
    If _KeyDown(20480) And size >= minsize And XC >= size + scale And YC >= size + scale Then size = size - scale ' UP Arrow

    If _KeyDown(18432) And size <= maxsize Then '                                         Press DOWN Arrow and Size is not at maxiumum size
        If _Width - size - (2 * scale) > XC And _Height - size - (2 * scale) > YC Then '  is not off right or bottom of screen
            If XC >= size + (2 * scale) And YC >= size + (2 * scale) Then '               is not off left or top of screen
                size = size + scale '                                                     Increase Size of shape
            End If
        End If
    End If

    If _KeyDown(19200) And spinspeed > -0.02 Then spinspeed = spinspeed - 0.001 '         Left Arrow Key - Decrease Spin Speed
    If _KeyDown(19712) And spinspeed < 0.02 Then spinspeed = spinspeed + 0.001 '          Right Arrow Key - Increase Spin Speed

    If (_KeyDown(81) Or _KeyDown(113)) And Abs(dx) > 1 Then '                             Press Q, reduce X direction
        If Abs(dx) >= 1 And Abs(dx) <= maxdxy Then dx = Sgn(dx) * Abs(dx) - (Sgn(dx) * 1)
    End If

    If (_KeyDown(87) Or _KeyDown(119)) And Abs(dx) < maxdxy Then '                        Press W, increase X direction
        If Abs(dx) >= 1 And Abs(dx) <= maxdxy Then dx = Sgn(dx) * Abs(dx) + (Sgn(dx) * 1)
    End If

    If (_KeyDown(69) Or _KeyDown(101)) And Abs(dy) < maxdxy Then '                        Press E, increase Y direction
        If Abs(dy) >= 1 And Abs(dy) <= maxdxy Then dy = Sgn(dy) * Abs(dy) + (Sgn(dy) * 1)
    End If

    If (_KeyDown(68) Or _KeyDown(100)) And Abs(dy) > 1 Then '                             Press D, decrease Y direction
        If Abs(dy) >= 1 And Abs(dy) <= maxdxy Then dy = Sgn(dy) * Abs(dy) - (Sgn(dy) * 1)
    End If

    If _KeyDown(45) And N > 3 Then N = N - 1 '                                            Press - key, decrease points on shape
    If _KeyDown(43) And N < 30 Then N = N + 1 '                                           Press + key, increase points on shape

    If _KeyDown(32) And framecounter Mod 3 = 0 Then shape = shape * -1 '                  Press Space to change shape, only once every 3 frames
    '##########################################################################################################################################

    '#####################################################################
    '## change direction of shape and keep it within the screen boundaries
    '#####################################################################
    If XC > _Width - size - scale Then dx = -dx
    If XC < size Then dx = -dx
    If YC >= _Height - size - scale Then dy = -dy
    If YC < size Then dy = -dy

    framecounter = (framecounter Mod 100) + 1
Loop Until _KeyDown(27)
System