'matrix.bas
'
'"Matrix" style graphic demo using freebasic

#Include "fbgfx.bi"

#Define screen_w 640
#Define screen_h 480
#Define screen_bpp 32
#Define fade 7
#Define change 3
#Define scroll 3
#Define msgx 25
#Define msgy 18

Const hiddenmsg As String = "When you see it..."

Type tmatrix
	char As UByte
	msg As Byte			'if part of the message, dont mess with it
	shade As integer	'255 is a bright green, 254-0 shades of green
End Type

Dim Shared matrix(0 To 79, 0 To 59) As tmatrix
Dim Shared tracers(0 To 79) As Integer
Dim Shared As Integer x, y, i, j

''BEGIN''

'set up the screen
ScreenRes screen_w, screen_h, screen_bpp, 2
ScreenSet 1, 0
'load the 8x8 character set
Width 80, 60
Randomize Timer
'reset our matrix
For y = 0 To 59
	For x = 0 To 79
		With matrix(x, y)
			.char = CUByte(Rnd * 256)
			.shade = 0
			.msg = 0
		End With
	Next
Next
'hide our message in the matrix
x = msgx
y = msgy
For i = 0 To Len(hiddenmsg)
	matrix(x, y).char = Asc(Mid(hiddenmsg, i+1, 1))
	matrix(x, y).msg = 1
	x = x + 1
Next
'reset our tracers (to create the same effect seen in the movie)
For i = 0 To 79
	tracers(i) = Int(Rnd * 60)
	matrix(i, tracers(i)).shade = 255
Next

'now we loop through the grid and draw it until the user decides to exit
Do
	Cls
	'lock the screen first
	ScreenLock
	For y = 0 To 59
		For x = 0 To 79
			With matrix(x, y)
				j = Int(Rnd * change)
				If j = 0 And .msg = 0 Then .char = CUByte(Rnd * 256)
				If .shade = 255 Then
					Draw String (x Shl 3, y Shl 3), Chr(.char), RGB(192, 255, 192)
				Else
					Draw String (x Shl 3, y Shl 3), Chr(.char), RGB(0, .shade+1, 0)
				EndIf
				.shade -= (Int(Rnd * fade) + 1)
				If .shade < 0 Then .shade = 0
			End With
		Next
	Next
	ScreenUnLock
	'draw a frame	
	ScreenCopy 1, 0
	Sleep 50, 1
	'loop through the tracers and move them downwards
	For i = 0 To 79
		j = Int(Rnd * scroll)
		If j > 0 Then 
			tracers(i) += 1
			If tracers(i) > 59 Then tracers(i) = 0
		EndIf
		matrix(i, tracers(i)).shade = 255
	Next
Loop Until MultiKey(fb.sc_escape)

''END''