cranpose-ui-graphics 0.1.167

use std::sync::{
    Mutex, PoisonError,
    atomic::{AtomicUsize, Ordering},
};

use crate::ShaderWarmUp;

static REQUESTED: Mutex<Vec<ShaderWarmUp>> = Mutex::new(Vec::new());
static REQUESTED_COUNT: AtomicUsize = AtomicUsize::new(0);

/// Asks every renderer to compile the pipelines of `warm_ups` on its
/// background compiler, before a frame needs them.
///
/// Call it where an app first builds what draws them, such as a widget's
/// first composition, so the pipelines are ready before that widget's
/// effect first draws, and an app compiles nothing for effects it never
/// builds. A warm-up requested twice is kept once. A renderer created later,
/// as after an Android surface loss, compiles every request made before it.
pub fn request_shader_warm_ups(warm_ups: impl IntoIterator<Item = ShaderWarmUp>) {
    let mut requested = REQUESTED.lock().unwrap_or_else(PoisonError::into_inner);
    for warm_up in warm_ups {
        if !requested.contains(&warm_up) {
            requested.push(warm_up);
        }
    }
    REQUESTED_COUNT.store(requested.len(), Ordering::Release);
}

/// The warm-ups requested after the first `seen`, in the order they were
/// requested: a renderer passes how many it has already queued.
pub fn shader_warm_ups_after(seen: usize) -> Vec<ShaderWarmUp> {
    if REQUESTED_COUNT.load(Ordering::Acquire) <= seen {
        return Vec::new();
    }
    let requested = REQUESTED.lock().unwrap_or_else(PoisonError::into_inner);
    requested
        .get(seen..)
        .map_or_else(Vec::new, <[ShaderWarmUp]>::to_vec)
}

#[cfg(test)]
#[path = "tests/shader_warm_up_tests.rs"]
mod tests;