Hello,
i have a question, another one) How can one determine one side or other side of rectangle?
Say i have a rect that 100 pixels wide and then i move another rectangle to it from side
how can i determine what side another rect hits without using any physics? How can i get x coordinates of rectangle corners for example?
thanks in advance [import]uid: 16142 topic_id: 16946 reply_id: 316946[/import]
a bit of maths, you need to draw these on paper and see…
I did not really understand your question other than the fact that you want to detect collision without using physics.
say you have rectangle A and rectangle B
A is at 10,10 and is 100x100
B is at 50,50 and is 200x100
the corners for A are
x ,y = 10, 10
x1,y = 110, 10
x ,y1 = 10,110
x1,y1 = 110,110
and, the corners for B are
x ,y = 50, 50
x1,y = 250, 10
x ,y1 = 50,110
x1,y1 = 250,110
you do not have to calculate all of these, but you need to check if the x,y of rectangle B fall within x,y and x1,y1
which can be managed as
if (rectB.x > rectA.x and rectB.x < rectA.x+rectA.contentWidth ) and (rectB.y > rectA.y and rectB.y < rectA.y+rectA.contentHeight ) then
–Well, congratulations!!! You are the proud owner of a collision
end
cheers,
?
[import]uid: 3826 topic_id: 16946 reply_id: 63535[/import]
thanks for answer
i’ll ask another question, if its not a problem
How to determine if object2 standing near object2 in 50(or whatever) pixel radius? or just 50 pixels left or right [import]uid: 16142 topic_id: 16946 reply_id: 63589[/import]
Search the forums for non-physics collisions. There are two easy to implement functions that test if two objects are occupying the same space, one for rectangles, the other for circles.
The circle one already has a radius parameter that you can provide a bigger area than the object to test. The rectangle version could be easily modified to pass a range parameter in to check if the collision happens in a bigger box than the physical rectangle.
[import]uid: 19626 topic_id: 16946 reply_id: 63594[/import]
I know that you don’t want to use physics but why? [import]uid: 24111 topic_id: 16946 reply_id: 63601[/import]
i just dont like it)many complications with all that “dynamic” and “kinematic” things…
why they cant just register collisions without restrains? [import]uid: 16142 topic_id: 16946 reply_id: 63602[/import]
Physics adds a lot of overhead and complexity if all you want to know is if to objects occupy the same space. [import]uid: 19626 topic_id: 16946 reply_id: 63607[/import]
so, i tried to use physics) why is this kind of thing not working? are physics cant detect collision while transitioning or is it because of the way “player” moves?
[lua]local player = display.newCircle(0,0,20)
player:setFillColor(255,0,0)
player.x = 50
player.y = _H-flor.height-player.height
player.visible = false
physics.addBody(player, “dynamic”)
player.name = “player”
local function going()
if left == 1 then
player.x = player.x - 3
end
if right == 1 then
player.x = player.x + 3
end
end
local npc = display.newCircle(0,0,25)
npc:setFillColor(0,255,0)
group:insert(npc)
physics.addBody(npc, “kinematic”)
local npc_rect = display.newRect(0,0,150,30)
group:insert(npc_rect)
npc_rect.x = npc.x
npc_rect.y = npc.y
physics.addBody(npc_rect, “kinematic”)
npc_rect.name = “rect”
function to_left()
if blo == true then
transition.to(group, {time=3000, x = group.x - 100, onComplete = to_right})
end
end
function to_right()
transition.to(group, {time=3000, x = group.x + 100, onComplete = to_left})
end
to_right()
local function onCollision(event)
if event.object1.name == “rect” and event.object2.name == “player” then
print(“lol”)
end
end
Runtime:addEventListener(“collision”, onCollision)[/lua]
any help is appreciated, i really need to understand this [import]uid: 16142 topic_id: 16946 reply_id: 63608[/import]