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Written by CR Team
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Friday, 07 August 2009 17:45 |
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In one of our previous article we talked about the use of BaMove xtra and use of mouse in 3d world. So how does one go about using the same to move a rigid body ( take the famous Arknoid game paddle as an example ). Much like the game 'Pong', the player controls the "Vaus", a space vessel that acts as the game's "paddle" which prevents a ball from falling from the playing field, attempting to bounce it against a number of bricks. -Wikipedia 
First we create the rigid body ... ( see the tutorials section ).
Then to initialize/synch the cursor and the rigid body ( the paddle in the this case ).
The following code snippet should do that:
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--some global variable to keep track of things
global p3d_worldPoint,mouse_click
on mouseDown me
--get the sprite handler
pstage = sprite(me.spritenum)
--physx is the name we gave to our physics member
physX = member("physX")
--3dworld , name of the 3d member to which physics id attached
p3dMember = member("3dworld")
--mouse_click, just a flag to avoid multiple clicks, set initially to 0
if mouse_click <> 1 then
rb_paddle = physX.getrigidbody("paddle_rb")
--make sure paddle rigid body is present
if rb_paddle <> void then
--set the mouse_click variable to 1, so multiple clicks are avoided
mouse_click = 1
--hiding the cursor
_player.cursor(200)
--get the mouse location on the sprite
lc_mouse_points = (the mouseloc) - point(pstage.left, pstage.top)
--get the current position of the paddle
p3d_worldPoint = pstage.camera.worldSpaceToSpriteSpace(rb_paddle.position)
--sync the mouse position to that of the rigid body
baMoveCursor( p3d_worldPoint.locH, p3d_worldPoint.locV )
end if
end if
end
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Now time to get the user input right when he uses the mouse !
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global mouse_click,p3d_worldPoint
--inside some function...
if mouse_click <> 0 then
lc_mouse_points = (the mouseloc) - point(pstage.left, pstage.top)
diff = lc_mouse_points - p3d_worldPoint
rb_paddle = physX.getRigidBody("paddle_rb")
diff_horizontal = diff.locH
diff_vertical = diff.locV
--some logic to restrict your paddle going beyond some range
--x-axis in this case
if (diff_horizontal > MAX_+ve_X) then
diff_horizontal = 350
end if
if (diff_horizontal < MAX_-ve_X) then
diff_horizontal = -350
end if
--the following parameters may need tweaking based on your world axis
rb_paddle.position = vector(diff_horizontal,diff_vertical,rb_paddle.position.z)
end if
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Thats it ! Your rigid body should follow the mouse pointer now with ease. The above logic can be used for a lot of other scenarios.
Explore them and let us know as well !!
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