Leafy trees
Draws leafy trees where the user clicks the mouse. The code uses a recursive branch drawing method, and it can be tinkered to make many different types of trees.
Original Author: Dan McCuaig
Assumptions
Paste the code into a form.
Code
'DrawTree - draws a tree recursively. Each recursion draws a branch,
'and then joins on five offshoots
'
'Parameters:
' x0 : start x location
' y0 : start y location
' h : height of tree
' a : angle of branch in degrees
' limit : how far to fork branches
' color of current branch
Sub DrawTree(ByVal x0 As Double, ByVal y0 As Double, ByVal h As Double, ByVal a As Double, ByVal limit As Integer, Optional ByVal colour As Long = -1)
Dim x1 As Double, y1 As Double
Dim x2 As Double, y2 As Double
Dim x3 As Double, y3 As Double
Dim x4 As Double, y4 As Double
Dim x5 As Double, y5 As Double
Dim rad As Double
Const pi As Double = 3.141592654
Const d2r As Double = pi / 180
If limit > 0 Then
If colour = -1 Then
colour = RGB(0, Rnd * 256, 0)
End If
rad = a * d2r 'convert angle to radians
'get locations for tree branch offshoots
'20% up the branch
x1 = x0 + 0.2 * h * Cos(rad)
y1 = y0 + 0.2 * h * Sin(rad)
'40% up the branch
x2 = x0 + 0.4 * h * Cos(rad)
y2 = y0 + 0.4 * h * Sin(rad)
'60% up the branch
x3 = x0 + 0.6 * h * Cos(rad)
y3 = y0 + 0.6 * h * Sin(rad)
'80% up the branch
x4 = x0 + 0.8 * h * Cos(rad)
y4 = y0 + 0.8 * h * Sin(rad)
'100% up the branch
x5 = x0 + h * Cos(rad)
y5 = y0 + h * Sin(rad)
'Draw branch
Line (x0, y0)-(x5, y5), colour
'Draw offshoots
DrawTree x1, y1, h * 0.4, a - 45, limit - 1 '-45degrees off
DrawTree x2, y2, h * 0.4, a + 45, limit - 1 '+45degrees off
DrawTree x3, y3, h * 0.4, a - 45, limit - 1
DrawTree x4, y4, h * 0.4, a + 45, limit - 1
DrawTree x5, y5, h * 0.4, a - 45, limit - 1
DrawTree x5, y5, h * 0.4, a, limit - 1
End If
End Sub
Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
'Draw tree with start color of brown
DrawTree X, Y, 1000, -90, 6, RGB(160, 82, 45)
End Sub
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