Created a custom texture packer

2 files changed, 155 insertions, 0 deletions

diff --git a/packer/Cargo.toml b/packer/Cargo.toml
new file mode 100644
index 0000000..d370392
--- /dev/null
+++ b/packer/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "packer"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+image = "0.24"
+exun = "0.2"
diff --git a/packer/src/lib.rs b/packer/src/lib.rs
new file mode 100644
index 0000000..06c66ae
--- /dev/null
+++ b/packer/src/lib.rs
@@ -0,0 +1,145 @@
+use std::sync::Arc;
+use std::{collections::HashMap, ops::Deref};
+
+use exun::RawUnexpected;
+use image::{GenericImage, RgbImage};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Rectangle {
+	pub x: u32,
+	pub y: u32,
+	pub width: u32,
+	pub height: u32,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct Texture {
+	id: Box<str>,
+	x: u32,
+	y: u32,
+	texture: Arc<RgbImage>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct ImageRect(Arc<RgbImage>, Box<str>);
+
+#[derive(Debug, Default, Clone)]
+pub struct RectanglePacker {
+	min_width: u32,
+	textures: Vec<ImageRect>,
+}
+
+impl PartialOrd for ImageRect {
+	fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+		Some(self.cmp(other))
+	}
+}
+
+impl Ord for ImageRect {
+	fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+		self.0.height().cmp(&other.0.height())
+	}
+}
+
+impl RectanglePacker {
+	pub fn new() -> Self {
+		Self {
+			min_width: 1,
+			textures: Vec::new(),
+		}
+	}
+
+	pub fn with_capacity(capacity: usize) -> Self {
+		Self {
+			min_width: 1,
+			textures: Vec::with_capacity(capacity),
+		}
+	}
+
+	pub fn capacity(&self) -> usize {
+		self.textures.capacity()
+	}
+
+	pub fn len(&self) -> usize {
+		self.textures.len()
+	}
+
+	pub fn is_empty(&self) -> bool {
+		self.textures.is_empty()
+	}
+
+	pub fn reserve(&mut self, additional: usize) {
+		self.textures.reserve(additional)
+	}
+
+	pub fn shrink_to_fit(&mut self) {
+		self.textures.shrink_to_fit()
+	}
+
+	pub fn add_texture(&mut self, name: Box<str>, texture: Arc<RgbImage>) {
+		if texture.width() > self.min_width {
+			self.min_width = texture.width() + 1;
+		}
+		self.textures.push(ImageRect(texture, name));
+	}
+
+	fn pack(&mut self) -> (Vec<Texture>, u32, u32) {
+		let image_width = self.min_width;
+
+		let mut x_position = 0;
+		let mut y_position = 0;
+		let mut largest_row_height = 0;
+		let mut rectangles = Vec::with_capacity(self.textures.len());
+
+		self.textures.sort();
+		for texture in &self.textures {
+			// loop to the next row if we've gone off the edge
+			if (x_position + texture.0.width()) > image_width {
+				y_position += largest_row_height;
+				x_position = 0;
+				largest_row_height = 0;
+			}
+
+			// set the rectangle position
+			let x = x_position;
+			let y = y_position;
+
+			x_position += texture.0.width();
+
+			if texture.0.height() > largest_row_height {
+				largest_row_height = texture.0.height();
+			}
+
+			rectangles.push(Texture {
+				id: texture.1.clone(),
+				x,
+				y,
+				texture: texture.0.clone(),
+			});
+		}
+
+		let total_height = y_position + largest_row_height;
+
+		(rectangles, image_width, total_height)
+	}
+
+	pub fn output(&mut self) -> Result<(RgbImage, HashMap<Box<str>, Rectangle>), RawUnexpected> {
+		let (rectangles, image_width, image_height) = self.pack();
+		let mut image = RgbImage::new(image_width, image_height);
+		let mut ids = HashMap::with_capacity(rectangles.len());
+		for rectangle in rectangles {
+			image.copy_from(rectangle.texture.deref(), rectangle.x, rectangle.y)?;
+			ids.insert(
+				rectangle.id,
+				Rectangle {
+					x: rectangle.x,
+					y: rectangle.y,
+					width: rectangle.texture.width(),
+					height: rectangle.texture.height(),
+				},
+			);
+		}
+
+		Ok((image, ids))
+	}
+}