Hi!
Strangely enough (?) it seems one can't pass normal functions
to GLFW.Set...Callback. But if you just want to store the positions in some
object (maybe to change its properties) you can do something like this
# some type which needs positions
type Foo
x::Float64
y::Float64
end
setpos!(foo::Foo, x, y ) = (foo.x = x; foo.y = y; foo)
# initialize a Foo
foo = Foo(0.,0.)
# this is the callback function which updates the coordinates in foo
function poscb(foo::Foo, x, y)
println("cursor pos: $x, $y")
setpos!(foo, x, y)
nothing
end
# ...
GLFW.SetCursorPosCallback(window, (x,y)->poscb(foo, x,y))
# ...
In the main loop you can now draw/use foo with updated positions.
Hope it helps,
Alex.
PS: The question about the Julian way of doing event processing/callbacks
is quite interesting. Reactive.jl is pretty cool, but I don't know if there
is a "consensus" that it is the recommended or preferred way of doing this.
On Wednesday, 6 May 2015 22:49:00 UTC+2, Elburz Sorkhabi wrote:
>
> Hey there, about a week into Julia now and really enjoying it.
>
> I have a quick question that I feel is pretty simple but I can't seem to
> find any good examples in the docs or by looking through other peoples
> code, and I'm quite new to programming callbacks in general.
>
> I'm trying to get keyboard and mouse inputs from this GLFW.jl saved into a
> variable:
>
> https://github.com/JuliaGL/GLFW.jl/blob/master/examples/callbacks.jl
>
> In this example callbacks are used to update and println() the values. I
> tried a few different things like replacing the println() with another
> function that would assign the values to some variables, as well as just
> assigning variables after the ->, but I must be missing something simple as
> those didn't seem to work properly.
>
> What I'd really like is to be able to write something like :
>
> mouseCoordinates = GLFW.SetCursorPosCallback(window, (x, y))
>
> and have a 2 element set with the x and y position easily accessible.
>
> For reference here is the implementation of the SetCursorPosCallback
> function (near the bottom of this page):
>
> https://github.com/JuliaGL/GLFW.jl/blob/master/src/glfw3.jl
>
> And what seems to be happening is that the function is being passed into a
> macro here:
>
> https://github.com/JuliaGL/GLFW.jl/blob/master/src/util.jl
>
> Any help even just walking me through it would be greatly appreciated.
>
>
