Microsoft Small Basic

Program Listing: SGN809

List Program

GraphicsWindow.BackgroundColor = "SkyBlue"
gameWidth = "450"
gameHeight = "350"
GraphicsWindow.Width = gameWidth
GraphicsWindow.Height = gameHeight
GraphicsWindow.Left = Desktop.Width / 2 - GraphicsWindow.Width / 2
GraphicsWindow.Top = Desktop.Height / 2 - GraphicsWindow.Height / 2

beec = 0
heading = 1
getgoing = 0
dirdeg = 0
dirreq = "s"
dirarr = 0

shoot = 0

GraphicsWindow.Show()
GraphicsWindow.KeyDown = getcommand



sx = 100 'ship x starting position
sy = 100 'ship y starting position
wx = 1 ' begin wind x
wy = 1 ' begin wind y
windhead = 0
GraphicsWindow.PenWidth = 1
GraphicsWindow.PenColor = "Brown"
GraphicsWindow.BrushColor = "Brown"
myship = Shapes.AddEllipse(5, 11)
Shapes.Move(myship, sx, sy)

saveshead = ""
savewhead = ""
savesarr = 0
savewarr = 0


'************************************************
'** dr[] controls how fast the ship moves into or
'** with the wind, depending on its heading.
'************************************************
dr[0] = .2 '.2
dr[1] = .3 '.4
dr[2] = .5 '.8
dr[3] = .4 '.6
dr[4] = .4
dr[5] = .5
dr[6] = .3
dr[7] = .2


run()



Sub run
running = 1

While running = 1
'find the ship heading
dirdeg = heading
calcdir()
saveshead = dirreq
savesarr = dirarr

'find the wind heading
dirdeg = windhead
calcdir()
savewhead = dirreq
savewarr = dirarr

GraphicsWindow.Title = "shiph: " + saveshead +", windh: "+ savewhead + ", " + modspeed
Program.Delay(20)
If getgoing = 1 Then
getwind()
calcmove()
moveship()
endif

If shoot = 1 Then
doshoot()
EndIf
endwhile

endsub



'************************************************
'** Moves the ship. The variable 'beec' is the main
'** variable that changes speed.
'************************************************
Sub moveship
sx = Math.Remainder(sx + (Math.Cos(Math.GetRadians(heading - 90)) * beec) + gameWidth, gameWidth)
sy = Math.Remainder(sy + (Math.Cos(Math.GetRadians(heading)) * beec) + gameHeight, gameHeight)
Shapes.Move(myship, sx, sy)
endsub



'************************************************
'** Generates wind direction and controls when
'** the wind changes direction
'************************************************
wdelay = 0
Sub getwind
wdelay = wdelay + 1
If wdelay = 1000 then
windhead = Math.Remainder(Math.GetRandomNumber(360), 360)
wdelay = 1
endif

endsub




'************************************************
'** Modifies the speed of the ship by calculating
'** the wind speed and direction
'************************************************
Sub calcmove
modspeed = math.abs(savesarr - savewarr)
beec = ((beec * dr[modspeed]) + .11)
endsub





'************************************************
'** narrows the 360 possible points of the
'** compas down to eight. This is used in run()
'** where run queries both the wind heading
'** and the ship heading.
'************************************************
Sub calcdir
If dirdeg < 45 then
dirreq = "sse"
dirarr = 4

endif

If dirdeg > 315 then
dirreq = "ssw"
dirarr = 5
endif

If dirdeg < 90 and dirdeg > 45 then
dirreq = "se"
dirarr = 3
endif

If dirdeg < 135 and dirdeg > 90 then
dirreq = "ne"
dirarr = 2
endif

If dirdeg < 180 and dirdeg > 135 then
dirreq = "nne"
dirarr = 1
endif

If dirdeg < 225 and dirdeg > 180 then
dirreq = "nnw"
dirarr = 8
endif

If dirdeg < 270 and dirdeg > 225 then
dirreq = "nw"
dirarr = 7
endif

If dirdeg < 315 and dirdeg > 270 then
dirreq = "sw"
dirarr = 6
endif
endsub




'************************************************
'** Listen for keystrokes
'************************************************
Sub getcommand
If(GraphicsWindow.LastKey = "Up") Then
getgoing = 1
EndIf

If(GraphicsWindow.LastKey = "Left") Then
heading = math.Abs(Math.Remainder(heading + .9, 360))
vhead = heading * -1
Shapes.Rotate(myship, vhead)
endif

If(GraphicsWindow.LastKey = "Right") Then
If heading = 0 Then
heading = 360
EndIf
heading = Math.Remainder(heading - .9, 360)
vhead = heading * -1
Shapes.Rotate(myship, vhead)
endif

If(GraphicsWindow.LastKey = "Down") Then
beec = 0
getgoing = 0
EndIf

If(GraphicsWindow.LastKey = "Space") Then
shoot = 1
EndIf
EndSub

Sub doshoot

EndSub