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;Little scrolling engine by Andre Guerreiro (byo)
;It's very simple and the code is a mess so if you can
;give me hints on easier approaches, I'd gladly appreciate it. :)

;Oh, and Purebasic rules!
;==========================================================


;Declaration of the things (procedures) to come!
Declare Init()
Declare DeInit()
Declare DrawMini()

;Some constants for the basic stuff as ScreenWidth and ScreenHeight for speed
#sW = 640
#sH = 480

;Enumerating images
Enumeration
	#map
	#mini
EndEnumeration

;Let's include images in the executables the PB traditional way
DataSection
	map:
		IncludeBinary "map.jpg"
	mini:
		IncludeBinary "mini.jpg"
EndDataSection

;Variables that will be there til the end
Global mouseX1, mouseX2, mouseY1, mouseY2 
Global map, mini, mapX, mapY, scrollSpeed, miniX, miniY, miniW, miniH
Global MiniSelectable, miniMouseX1, miniMouseY1
Global mapW, mapH

;Every initialization before the loop is done inside this procedure
;for easy reading.
Init()

;The famous loop
Repeat
	ExamineKeyboard()
	ExamineMouse()
	
	;I'm not sure if this is working or not. Tell me if it's not, please.
	ReleaseMouse(1-IsScreenActive())
	
	;Our way out of the program by pressing ESC
	If KeyboardPushed(#PB_Key_Escape)
		Exit = #True
	EndIf
	
	;Captures the mouse inside the minimap and moves the map according to its location.
	;My math is ugly so please help me improve, commenting what you're doing cause I
	;suck at math. It's just about proportion and location.
	If MouseButton(#PB_MouseButton_Left)
		If (MouseX() >= miniX) And (MouseX() < miniX+miniW) And (MouseY() >= miniY) And (MouseY() < miniY+miniH)
			If MB_Left <> 2
				mapX = -((MouseX()-#sW/20)-miniX)*20-#sW/2
				mapY = -((MouseY()-#sH/20)-miniY)*20-#sH/2
				If mapX > 0 : mapX = 0 : EndIf
				If mapY > 0 : mapY = 0 : EndIf
				If mapX < -ImageWidth(#map)+#sW : mapX = -ImageWidth(#map)+#sW : EndIf
				If mapY < -ImageHeight(#map)+#sH : mapY = -ImageHeight(#map)+#sH : EndIf
			EndIf
		Else
			;Thanks to Joakim Christiansen for this next little workaround routine
			;while there is no MouseDown() native event.
			If MB_Left = 0 
				MB_Left = 1 
			Else 
				MB_Left = 2 
			EndIf
		EndIf
	Else
		If MB_Left = 3 
			MB_Left = 0 
		ElseIf MB_Left = 2 
			MB_Left = 3 
		EndIf 
	EndIf
	
	;This is where we draw everything.
	StartDrawing(ScreenOutput())
	DrawImage(ImageID(#map), mapX, mapY)
	DrawMini()
	DrawingMode(#PB_2DDrawing_Transparent)
	DrawText(miniX+miniW+5, miniY+5, "This is a little scrolling demo with minimap made by byo (Andre Guerreiro)", #White)
	DrawText(miniX+miniW+5, miniY+18, "Use the arrow keys or the mouse to scroll. You can drag a selectable region", #White)
	DrawText(miniX+miniW+5, miniY+31, "by holding the left mouse button. Sorry for the messy code.", #White)
	DrawText(miniX+miniW+5, miniY+60, "Click on the minimap and you'll get to the point selected by the mouse", #White) 
	StopDrawing()
	
	;Let's capture the left mouse button and create a selecion region if it's down.
	;0 is UP, 1 is PRESSED, 2 is DOWN, 3 is RELEASED
	Select MB_left
		Case 0			
			FlipBuffers()	
		Case 1
			mouseX1 = MouseX()
			mouseY1 = MouseY()
			miniMouseX1 = mouseX1
			miniMouseY1 = mouseY1
		Case 2
			mouseX2 = MouseX() - mouseX1
			mouseY2 = MouseY() - mouseY1
			
			StartDrawing(ScreenOutput())
			Line(mouseX1, mouseY1, mouseX2, 0, #Green)
			Line(mouseX1, mouseY1, 0, mouseY2, #Green)
			Line(MouseX(), mouseY1, 0, mouseY2, #Green)
			Line(mouseX1, mouseY1+mouseY2, mouseX2, 0, #Green)				
			DrawMini()			
			StopDrawing()
			
			FlipBuffers()
		Case 3
			MB_Left = 0
	EndSelect
	
	;Scrolling the map if the mouse it's on the 4 edges of the screen or if the
	;player touches the arrow keys.
	If (MouseX() = 0) Or (KeyboardPushed(#PB_Key_Left))
		mapX + scrollSpeed		
		If mapX > 0
			mapX = 0
		Else
			mouseX1 + scrollSpeed
		EndIf
	EndIf
	If (MouseY() = 0) Or (KeyboardPushed(#PB_Key_Up))
		mapY + scrollSpeed		
		If mapY > 0
			mapY = 0
		Else
			mouseY1 + scrollSpeed	
		EndIf
	EndIf
	If (MouseX() = #sW-1) Or (KeyboardPushed(#PB_Key_Right))
		mapX - scrollSpeed		
		If mapX < -ImageWidth(#map)+#sW
			mapX = -ImageWidth(#map)+#sW
		Else
			mouseX1 - scrollSpeed	
		EndIf
	EndIf
	If (MouseY() = #sH-1) Or (KeyboardPushed(#PB_Key_Down))
		mapY - scrollSpeed		
		If mapY < -ImageHeight(#map)+#sH
			mapY = -ImageHeight(#map)+#sH
		Else
			mouseY1 - scrollSpeed	
		EndIf
	EndIf			
	
	;This is required for dealing with the window events behind the screen
	;Thanks to netmaestro.
	While WindowEvent() : Wend
Until Exit
;End of our confused loop.

;A little routine for freeing stuff inside variables.
DeInit()



Procedure Init()
	InitSprite()
	
	OpenWindow(0, #PB_Ignore, #PB_Ignore, #sW, #sH, "byo game", #PB_Window_SystemMenu | #PB_Window_ScreenCentered | #PB_Window_MinimizeGadget)
	OpenWindowedScreen(WindowID(0), 0, 0, #sW, #sH, #False, 0, 0)
	
	ClearScreen(#Black)
	StartDrawing(ScreenOutput())
	DrawingMode(#PB_2DDrawing_Transparent)
	DrawText(#sW-100, #sH-40, "LOADING...", #White)
	StopDrawing()
	
	FlipBuffers()
	
	InitKeyboard()
	InitMouse()
	
	ShowCursor_(#True)
	MouseLocate(#sW/2, #sH/2)
	
	UseJPEGImageDecoder()
	
	
	scrollSpeed = 10	
	mapX = 0 : mapY = 0
	mapW = 2400 : mapW = 2760
	miniX = 4 : miniY = #sH-142
	miniW = 120 : miniH = 138
	
	CatchImage(#map, ?map)
	CatchImage(#mini, ?mini)	
	
EndProcedure

Procedure DeInit()
	FreeImage(#map)
	FreeImage(#mini)	
EndProcedure

Procedure DrawMini()
	posX = miniX-mapX/20
	posY = miniY-mapY/20
	posW = (#sW/20)-1
	posH = (#sH/20)-1

	DrawImage(ImageID(#mini), miniX, miniY)
	Line(posX, posY, posW, 0, #White)
	Line(posX, posY, 0, posH, #White)
	Line(posX, posY+(posH), posW, 0, #White)
	Line(posX+(posW), posY, 0, posH+1, #White)	
EndProcedure