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https://github.com/storytold/vectorcraft.git
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37 lines
1.6 KiB
Rust
37 lines
1.6 KiB
Rust
use super::*;
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/// A render context on the calling thread. vello_cpu's `RenderContext::new` defaults to a
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/// multithreaded dispatcher, which panics on filter effects (glows, shadows, blur).
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pub(crate) fn single_threaded_context(w: u16, h: u16) -> RenderContext {
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RenderContext::new_with(w, h, vello_cpu::RenderSettings { num_threads: 0, ..Default::default() })
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}
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/// Preferred rasterizer thread count set by the app (Preferences → Performance); negative = automatic.
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static THREADS_OVERRIDE: std::sync::atomic::AtomicI32 = std::sync::atomic::AtomicI32::new(-1);
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/// Override the worker-thread count used by renderers created from now on (`None` = automatic).
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pub fn set_default_threads(n: Option<u16>) {
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THREADS_OVERRIDE.store(n.map_or(-1, i32::from), std::sync::atomic::Ordering::Relaxed);
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}
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/// Rasterizer worker threads: 0 on wasm; otherwise one per core up to 8, leaving a core free. On a
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/// 10-core machine 8 workers render a 50,000-path page 1.4× faster than 4 (9 are slower again);
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/// the pixels don't depend on the count (`pixels_do_not_depend_on_the_thread_count`).
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pub fn default_threads() -> u16 {
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#[cfg(target_arch = "wasm32")]
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{
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0
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}
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#[cfg(not(target_arch = "wasm32"))]
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{
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let o = THREADS_OVERRIDE.load(std::sync::atomic::Ordering::Relaxed);
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if o >= 0 {
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return o.min(64) as u16;
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}
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if std::env::var_os("VECTORCRAFT_RENDER_THREADS").is_some() {
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return std::env::var("VECTORCRAFT_RENDER_THREADS").ok().and_then(|v| v.parse().ok()).unwrap_or(0);
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}
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std::thread::available_parallelism().map(|n| (n.get().saturating_sub(1)).min(8) as u16).unwrap_or(0)
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}
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}
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