Extract gbrush (#2784)

node-graph/gbrush/src/brush_cache.rs

@@ -0,0 +1,184 @@
+use crate::brush_stroke::BrushStroke;
+use crate::brush_stroke::BrushStyle;
+use dyn_any::DynAny;
+use graphene_core::instances::Instance;
+use graphene_core::raster_types::CPU;
+use graphene_core::raster_types::Raster;
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::sync::Arc;
+use std::sync::Mutex;
+
+#[derive(Clone, Debug, PartialEq, DynAny, Default, serde::Serialize, serde::Deserialize)]
+struct BrushCacheImpl {
+	// The full previous input that was cached.
+	prev_input: Vec<BrushStroke>,
+
+	// The strokes that have been fully processed and blended into the background.
+	#[serde(deserialize_with = "graphene_core::raster::image::migrate_image_frame_instance")]
+	background: Instance<Raster<CPU>>,
+	#[serde(deserialize_with = "graphene_core::raster::image::migrate_image_frame_instance")]
+	blended_image: Instance<Raster<CPU>>,
+	#[serde(deserialize_with = "graphene_core::raster::image::migrate_image_frame_instance")]
+	last_stroke_texture: Instance<Raster<CPU>>,
+
+	// A cache for brush textures.
+	#[serde(skip)]
+	brush_texture_cache: HashMap<BrushStyle, Raster<CPU>>,
+}
+
+impl BrushCacheImpl {
+	fn compute_brush_plan(&mut self, mut background: Instance<Raster<CPU>>, input: &[BrushStroke]) -> BrushPlan {
+		// Do background invalidation.
+		if background != self.background {
+			self.background = background.clone();
+			return BrushPlan {
+				strokes: input.to_vec(),
+				background,
+				..Default::default()
+			};
+		}
+
+		// Do blended_image invalidation.
+		let blended_strokes = &self.prev_input[..self.prev_input.len().saturating_sub(1)];
+		let num_blended_strokes = blended_strokes.len();
+		if input.get(..num_blended_strokes) != Some(blended_strokes) {
+			return BrushPlan {
+				strokes: input.to_vec(),
+				background,
+				..Default::default()
+			};
+		}
+
+		// Take our previous blended image (and invalidate the cache).
+		// Since we're about to replace our cache anyway, this saves a clone.
+		background = std::mem::take(&mut self.blended_image);
+
+		// Check if the first non-blended stroke is an extension of the last one.
+		let mut first_stroke_texture = Instance {
+			instance: Raster::<CPU>::default(),
+			transform: glam::DAffine2::ZERO,
+			..Default::default()
+		};
+		let mut first_stroke_point_skip = 0;
+		let strokes = input[num_blended_strokes..].to_vec();
+		if !strokes.is_empty() && self.prev_input.len() > num_blended_strokes {
+			let last_stroke = &self.prev_input[num_blended_strokes];
+			let same_style = strokes[0].style == last_stroke.style;
+			let prev_points = last_stroke.compute_blit_points();
+			let new_points = strokes[0].compute_blit_points();
+			let is_point_prefix = new_points.get(..prev_points.len()) == Some(&prev_points);
+			if same_style && is_point_prefix {
+				first_stroke_texture = std::mem::take(&mut self.last_stroke_texture);
+				first_stroke_point_skip = prev_points.len();
+			}
+		}
+
+		self.prev_input = Vec::new();
+		BrushPlan {
+			strokes,
+			background,
+			first_stroke_texture,
+			first_stroke_point_skip,
+		}
+	}
+
+	pub fn cache_results(&mut self, input: Vec<BrushStroke>, blended_image: Instance<Raster<CPU>>, last_stroke_texture: Instance<Raster<CPU>>) {
+		self.prev_input = input;
+		self.blended_image = blended_image;
+		self.last_stroke_texture = last_stroke_texture;
+	}
+}
+
+impl Hash for BrushCacheImpl {
+	// Zero hash.
+	fn hash<H: std::hash::Hasher>(&self, _state: &mut H) {}
+}
+
+#[derive(Clone, Debug, Default)]
+pub struct BrushPlan {
+	pub strokes: Vec<BrushStroke>,
+	pub background: Instance<Raster<CPU>>,
+	pub first_stroke_texture: Instance<Raster<CPU>>,
+	pub first_stroke_point_skip: usize,
+}
+
+#[derive(Debug, DynAny, serde::Serialize, serde::Deserialize)]
+pub struct BrushCache {
+	inner: Arc<Mutex<BrushCacheImpl>>,
+	proto: bool,
+}
+
+impl Default for BrushCache {
+	fn default() -> Self {
+		Self::new_proto()
+	}
+}
+
+// A bit of a cursed implementation to work around the current node system.
+// The original object is a 'prototype' that when cloned gives you a independent
+// new object. Any further clones however are all the same underlying cache object.
+impl Clone for BrushCache {
+	fn clone(&self) -> Self {
+		if self.proto {
+			let inner_val = self.inner.lock().unwrap();
+			Self {
+				inner: Arc::new(Mutex::new(inner_val.clone())),
+				proto: false,
+			}
+		} else {
+			Self {
+				inner: Arc::clone(&self.inner),
+				proto: false,
+			}
+		}
+	}
+}
+
+impl PartialEq for BrushCache {
+	fn eq(&self, other: &Self) -> bool {
+		if Arc::ptr_eq(&self.inner, &other.inner) {
+			return true;
+		}
+
+		let s = self.inner.lock().unwrap();
+		let o = other.inner.lock().unwrap();
+
+		*s == *o
+	}
+}
+
+impl Hash for BrushCache {
+	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+		self.inner.lock().unwrap().hash(state);
+	}
+}
+
+impl BrushCache {
+	pub fn new_proto() -> Self {
+		Self {
+			inner: Default::default(),
+			proto: true,
+		}
+	}
+
+	pub fn compute_brush_plan(&self, background: Instance<Raster<CPU>>, input: &[BrushStroke]) -> BrushPlan {
+		let mut inner = self.inner.lock().unwrap();
+		inner.compute_brush_plan(background, input)
+	}
+
+	pub fn cache_results(&self, input: Vec<BrushStroke>, blended_image: Instance<Raster<CPU>>, last_stroke_texture: Instance<Raster<CPU>>) {
+		let mut inner = self.inner.lock().unwrap();
+		inner.cache_results(input, blended_image, last_stroke_texture)
+	}
+
+	pub fn get_cached_brush(&self, style: &BrushStyle) -> Option<Raster<CPU>> {
+		let inner = self.inner.lock().unwrap();
+		inner.brush_texture_cache.get(style).cloned()
+	}
+
+	pub fn store_brush(&self, style: BrushStyle, brush: Raster<CPU>) {
+		let mut inner = self.inner.lock().unwrap();
+		inner.brush_texture_cache.insert(style, brush);
+	}
+}