Tile Collision help

Hi all, I need some help with the code below, specifically detecting collisions correctly

if I move with increments of 32(tile size) collision is perfect, but obviously this is not ideal, so if I move say 3 unit increments, collision gets screwy, as in the example below. Can anyone help me this ?

'tile map example by Deux


Strict
Graphics 640,480,0

Const TILE_TYPE_WALL=1
Const TILE_TYPE_ROOF=2
Const TILE_TYPE_GROUND=3

Const MAP_WIDTH = 10
Const MAP_HEIGHT = 10



'SetClsColor 155,155,155
Type TTile
	Field x#
	Field y#
	Field width#
	Field height#
	Field red#
	Field green#
	Field blue#
	Field TileType%
	Field image:TImage
End Type


Global map[] = [2,2,2,2,2,2,2,2,2,2,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1,3,3,3,3,3,3,3,3,3,3]

Global TileList:TList=CreateList()

Global playery#=64
Global playerx#=64
Global oldx#
Global oldy#

Global x#
Global y#



Function LoadMap()

	Local tile_countx%=0
	Local tile_county%=0
	
	For Local x%=EachIn map
		Local t:TTile = New TTile
		If(tile_countx = MAP_WIDTH) Then
			tile_county :+1
			tile_countx = 0
		End If	
		
		
		Select x
		
			Case 1
				t.red# = tile_countx*10
				t.green# = tile_county*10
				t.blue# = 125
				t.width#=32
				t.height#=32
				t.x# = (tile_countx)*t.width#
				t.y#=(tile_county)*t.height#
				t.TileType = TILE_TYPE_WALL
				TileList.AddLast t
			Case 2
				t.red# = tile_countx*10
				t.green# = tile_county*10
				t.blue# = 125
				t.width#=32
				t.height#=32
				t.x# = (tile_countx)*t.width#
				t.y#=(tile_county)*t.height#
				t.TileType = TILE_TYPE_ROOF
				TileList.AddLast t
			Case 3
				t.red# = tile_countx*10
				t.green# = tile_county*10
				t.blue# = 125
				t.width#=32
				t.height#=32
				t.x# = (tile_countx)*t.width#
				t.y#=(tile_county)*t.height#
				t.TileType = TILE_TYPE_GROUND
				TileList.AddLast t
			
		End Select
			
	tile_countx :+ 1


	Next

End Function

Function RenderMap()
	For Local t:TTile=EachIn TileList
		SetColor t.red#,t.green#,t.blue#
		DrawRect t.x#,t.y#,32,32
		DrawText t.tiletype,t.x#,t.y#
	Next
End Function


LoadMap()

HideMouse

While Not KeyDown(KEY_ESCAPE)

	RenderMap()
	oldx# = playerx#
	oldy# = playery#

	If KeyDown(KEY_LEFT) playerx# :-3
	If KeyDown(KEY_RIGHT) playerx# :+3
	If KeyDown(KEY_UP) playery# :-3
	If KeyDown(KEY_DOWN) playery# :+3
	
	Local index:Int = playerx#/32+(playery#/32*MAP_HEIGHT)
	DrawText map[index],10,50
	
	If map[index] = 0 Then
	Else
		playerx# = oldx#
		playery# = oldy#
		
	End If
	
	DrawRect  playerx#,playery#,32,32
	
	Flip
	FlushMem
	Cls
	
	
Wend