AbdurRahman
Member
Hi, I'm trying to revolve earth image around sun image making an orbit without using 3rd party libraries or builtin functions.
So here's what I achieved:
If you notice its revolves in rectangle but not in circle.
So whats correct formula for moving it in circle ?
Here's my current code:
This is function that takes child image and revolve around parent image in within specified speed (latency in ms).
I call it like:
So here's what I achieved:
If you notice its revolves in rectangle but not in circle.
So whats correct formula for moving it in circle ?
Here's my current code:
This is function that takes child image and revolve around parent image in within specified speed (latency in ms).
B4X:
Sub revolve( parent As ImageView, child As ImageView, latency As Int)
Do While True
Dim parent_vertical_center As Int = parent.Top + ( parent.Height / 2 )
Dim child_vertical_center As Int = child.Top + ( child.Height / 2 )
Dim child_horizontal_center As Int = child.Left + ( child.Width / 2 )
Dim parent_horizontal_center As Int = parent.Left + ( parent.Width / 2 )
Dim IsChildUpperThanParent As Boolean = child_vertical_center <= parent_vertical_center
Dim IsChildBehindThanParent As Boolean = child_horizontal_center <= parent_horizontal_center
child.Left = child.Left + IIf(IsChildUpperThanParent, 1,-1) 'If child is topper than parent, then send child to right, else to left
child.Top = child.Top + IIf(IsChildBehindThanParent, -1, 1) 'If child is behind parent, then send child to bottom, else to top
Sleep(latency)
Loop
End SubI call it like:
B4X:
Sub Globals
Private sun As ImageView
Private earth As ImageView
End Sub
Sub Activity_Create(FirstTime As Boolean)
Activity.LoadLayout("Layout")
sun.Bitmap= LoadBitmap(File.DirAssets, "sun.png")
earth.Bitmap= LoadBitmap(File.DirAssets, "earth.png")
revolve(sun, earth, 20)
End Sub