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Nannou model requires a function pointer: How to return a function pointer
Trying to make a nannou app from the template but with a customizable model()
function.
The template has this main()
:
fn main() {
nannou::app(model).update(update).run();
}
The model
that goes intot the app()
is a function that returns a Model
. My Model
struct is very simple:
struct Model {
color: Hsl,
max_time: u32,
counter: u32,
}
The model
function simply returns a Model
struct. But instead of hard coding the parameters in a model()
function I want a model_function_creator()
that takes max_time
and a color_tuple
, captures them and returns a model
function that is parameterized.
I tried something like this:
fn model_function_creator(max_time: u32, color_tuple: (f32, f32, f32)) -> fn(&App) -> Model {
Box::new(move |_app: &App| Model {
color: hsl(color.0, color.1, color.2),
max_time: max_time,
counter: 0,
})
}
So that in main()
, I can call the model_function_creator
with custom parameters like this:
fn main() {
let max_time = 100;
let color = (0.3, 0.5, 0.5);
nannou::app(model_function_creator(max_time, color))
.update(update)
.simple_window(view)
.run();
}
But I get the following error messages:
expected `for<'r> fn(&'r nannou::App) -> Model` because of return type
and
expected fn pointer, found struct `Box`
How do I return a fn pointer
from a function and still have it capture the two parameter I pass to it.
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