Type collision
 Field img1,img2,x1,y1,x2,y2
End Type
Type collision_pos
 Field x,y,c.collision
End Type

Function CheckCollision.collision(img1,x1,y1,img2,x2,y2,bck1,bck2)
 x_abw=x1-x2:y_abw=y1-y2
 c.collision=New collision
 c\img1=img1:c\x1=x1:c\y1=y1
 c\img2=img2:c\x2=x2:c\y2=y2
 w1=ImageWidth(img1):h1=ImageHeight(img1)
 w2=ImageWidth(img2):h2=ImageHeight(img2)
 LockBuffer(ImageBuffer(img1))
 LockBuffer(ImageBuffer(img2))
 For x=0 To w1-1
  For y=0 To h1-1
   If x+x_abw>-1 And x+x_abw<w2 And y+y_abw>-1 And y+y_abw<h2 Then
    rgb1=ReadPixelFast(x,y,ImageBuffer(img1))
    rgb2=ReadPixelFast(x+x_abw,y+y_abw,ImageBuffer(img2))
    If rgb1<>bck1 And rgb2<>bck2 Then
     cp.collision_pos=New collision_pos
     cp\x=x+x1
     cp\y=y+y1
     cp\c=c
    End If
   End If
  Next
 Next
 UnlockBuffer(ImageBuffer(img1))
 UnlockBuffer(ImageBuffer(img2))
 Return c
End Function