2D Click 'n' Move

This code has been declared by its author to be Public Domain code.

2D Click 'n' Move by Paul Murray

2006

Very basic example of clicking a position on the screen and having an image move to that position automatically.

Download the *.bb file and image used in the example here...

http://www.sitesled.com/members/avengedsevenfold/clicknmove.zip

;************************************************
;	2D Click 'n' Move Example - written by Muzzer 2006	
;************************************************		
;				
; 	This code should give beginners an idea about	  
; 	moving an image to a position clicked on screen 	
;
;	Experienced Blitz users may think it's written
;	incorrectly, and they're probably right.
;
;	Anyway, it works.
;
;	Soldier sprite ripped from Metal Slug and grabbed from http://www.emugifs.emuita.it
;
;************************************************


AppTitle "2D Click 'n' Move Example"

Graphics 640,480,0,2

SetBuffer BackBuffer()

Global LastClickX = 400		;these coords are the same as the image start position to 
Global LastClickY = 240		;prevent it movingas soon as the program runs

Global ShipX = 400			;Image start postions
Global ShipY = 240

imgMove = LoadImage("soldier.PNG")
MaskImage imgMove,255,0,255

;------------------
;Main Loop
;------------------

While Not KeyHit(1)
Cls

	;set the LastClick positions
	If MouseDown(1) Then LastClickX = MouseX() LastClickY =  MouseY()	;if left button is pressed, set the LastClick variables to the current MouseX() and MouseY() coordinates
			
	
;DrawImage imgBack,0,0
DrawImage imgMove,ShipX - 32, ShipY -32	; the -32 offsets the image so the centre moves to the clicked point

	If ShipX < LastClickX Then ShipX = ShipX + 2	;if the image's X position is less than the LastClickX coord we set, move 2 units to the right
	
	If ShipX > LastClickX Then ShipX = ShipX - 2	;if the image's X position is greater than LastClickX, move 2 units to the left
		
	If ShipY < LastClickY Then ShipY = ShipY + 2	;if the image is lower than the LastClickY variable, move the image down
	
	If ShipY > LastClickY Then ShipY = ShipY - 2	;if the image is higher than the LastCLickY variable, move the image up
	
	
	;------------------
	;Debug Text	- simply to display the coordinates on screen
	;------------------
	

	Text 20,15, "Last ClickX = " + LastClickX	;displays the last 'X' coordinates clicked
	Text 20,30, "Last ClickY = " + LastClickY	;displays the last 'Y' coordinates clicked
	
	;constantly displays the Mouse coordinates
	Text 20,45, "Mouse X = " + MouseX()			
	Text 20,60, "Mouse Y = " + MouseY()
	
Flip

Wend

End

Comments

Jams

2006

Try this one:

Type point2
	Field x#, y#
End Type

;Calculates the distance between 2 2D points.
Function point2_CalcDistance#( A.point2, B.point2 )
	Local dX# = Abs( A\x - B\x )
	Local dY# = Abs( A\y - B\y )
	Return Sqr( (dX*dX) + (dY*dY) )
End Function

;Calculates the angle between 2 2D points.
Function point2_CalcAngle#( A.point2, B.point2 )
			Local dX# = A\x - B\x
			Local dY# = A\y - B\y
			Return ATan2( dX#, dY# ) +180
End Function

Local Pos.point2 = New point2; Current position.
Local Target.point2 = New point2; Target position.

;Move position and target to the centre of the screen.
Pos\x = 320: Pos\y = 240
Target\x = 320: Target\y = 240

Graphics 640,480, 0, 2
SetBuffer BackBuffer()
Repeat:Flip:Cls

	If MouseHit( 1 )
		;Update target with new mouse coords.
		Target\x = MouseX()
		Target\y = MouseY()
	EndIf

	;Check to see if the sprite is not already 'at' Target.
	If point2_CalcDistance( Pos, Target ) > 1
		Angle# = point2_CalcAngle( Pos, Target ); Calculate the angle needed to go to Target.
		Pos\x = Pos\x + Sin( Angle# );Move along x axis.
		Pos\y = Pos\y + Cos( Angle# );Move along y axis.
	EndIf

	Oval( pos\x-5, pos\y-5, 10, 10 ); Draw sprite

	Text 0,0,"Distance to target: "+ point2_CalcDistance( Pos, Target )
	Text 0,15,"Angle to target: "+ point2_CalcAngle( Pos, Target )

Until KeyHit(1)

Uses sin & cos to give more accurate movement. Also has 2 very useful functions to calculate the distance between two points, and to calculate the angle between 2 points.

octothorpe

2006

Local dX# = A\x - B\x
Local dY# = A\y - B\y
Return ATan2( dX#, dY# ) +180

If you subtract A from B instead, you won't need to add 180. ;)

Also, you might want to multiply the results of Sin() and Cos() by a constant (SPEED) to make it obvious how to change the speed.

Jams

2006

Ahh i thought there was something a little fishy about that +180, thanks octothorpe :)

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