scaling down

hi all, i dont know how to explain what i am trying to do so here it is in points:
-i have a cube and a sphere
-you move the sphere towards the cube
-once the cube and the sphere collide the cube gets shorter and the sphere dissapears

Everything works well until the cube and sphere collide. When they do, the sphere dissapears but the cube keeps getting shorter even though nothing is colliding with it. I kind of know why this is but i dont know how to change it. Here is the code (in the main loop):

If EntityCollided (sphere, type_cube) And health=>2 Then 
	y=y-1
	health=health-1
	HideEntity sphere
EndIf

ScaleEntity cube, x, y, z

i put health as 10 and y as 10 in the beginning. Does anyone know how i could make it so that when the sphere collides with the cube, the cube gets shorter by 1 and no more, until another sphere collides with it?

Thanks alot

sorry, i made a mistake..the stuff i wrote above happens when i dont include the part health=>2. When i do include it (the code above) then nothing happens; the cube stays the same.

here is the problem:

Graphics3D 1280,800
SetBuffer BackBuffer()

light=CreateLight()

cam=CreateCamera()

;collision types
type_sphere=1
type_cube=2

;the sphere
sphere=CreateSphere()
PositionEntity sphere, -4,0,20
EntityType sphere, type_sphere


;the cube
cube=CreateCube()
PositionEntity cube, 2,0,20
EntityType cube, type_cube

x=1
y=10
z=1



;collisions
Collisions type_sphere, type_cube, 2,1
Collisions type_cube, type_sphere, 2, 1

;health
health=10


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;MAIN LOOP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
While Not KeyDown(1)

;moving the sphere
If KeyDown(205) Then MoveEntity sphere, 0.1,0,0
If KeyDown(203) Then MoveEntity sphere, -0.1,0,0

;shortening the cube
If EntityCollided (sphere, type_cube) And health=>2 Then 
		y=y-1
		health=health-1
		HideEntity sphere
EndIf

ScaleEntity cube, x, y, z



UpdateWorld
RenderWorld

;diplaying the height of cube and the health
Text 20,20,"y:"+y
Text 100,20,"health:"+health
	
Flip
	
Wend
	
End

and here is what i would like to happen except instead of that happening every time you press the space bar, it happens each time there is a collision with the sphere and the cube..

Graphics3D 1280,800
SetBuffer BackBuffer()

light=CreateLight()

cam=CreateCamera()

type_sphere=1
type_cube=2

sphere=CreateSphere()
PositionEntity sphere, -4,0,20
EntityType sphere, type_sphere


x=1
y=10
z=1
cube=CreateCube()
PositionEntity cube, 2,0,20

EntityType cube, type_cube



Collisions type_sphere, type_cube, 2,1
Collisions type_cube, type_sphere, 2, 1

health=10


While Not KeyDown(1)


If KeyDown(205) Then MoveEntity sphere, 0.1,0,0
If KeyDown(203) Then MoveEntity sphere, -0.1,0,0

If KeyHit(57) And health=> 2 Then 
		y=y-1
		health=health-1
EndIf

ScaleEntity cube, x, y, z

	
UpdateWorld
RenderWorld

Text 20,20,"y:"+y
Text 100,20,"health:"+health
	
Flip
	
Wend
	
End

does anyone know?

The And operator in Blitz3D is actually bitwise.

The expression ( health >= 2 ) evaluates to 1 or 0, meaning True or False respectively.

The expression EntityCollided (sphere, type_cube) is simply an integer, the sphere's handle. As it happens this is always an even number. So when you combine them with

EntityCollided (sphere, type_cube) And health=>2

the result is 0. Thus your collision code is never executed. Change the test to

If EntityCollided (sphere, type_cube) <> 0 And health => 2 Then

*edit* what floyd said

thank you, that stops the cube from getting too small, meaning you can still see it but do you know what i could do to make the cube only get smaller by 1. What is happening now is that, when the sphere and the cube collide, the cube gets smaller from y=10 to y=1. what i am aiming for is when they collide, y=10 goes to y=9.

thanks

To get that, use a variable to store the collision. Then, use another variable to store the previous state of the collision:

oldcoll = coll
coll = (EntityCollided (sphere, type_cube) <> 0)

Now, you can compare coll to oldcoll, and if they are different you can respond to it, ie:

If coll and (not oldcoll) Then ..

yeees thank you so much Warner and Floyd. it works perfectly well now!!

thanks :D