Reworked sprite content

content/sprite.toml

@@ -27,8 +27,8 @@ file = "ship/gypsum.png"
 
 [sprite."ship::peregrine"]
 timing.duration = 2
-repeat = "reverse"
-random_start_frame = true
+top = "reverse"
+bot = "reverse"
 frames = [
 	"ship/peregrine/01.png",
 	"ship/peregrine/02.png",
@@ -73,7 +73,6 @@ file = "ui/landscape-mask.png"
 
 [sprite."particle::blaster"]
 timing.duration = 0.15
-repeat = "once"
 frames = [
 	"particle/blaster/01.png",
 	"particle/blaster/02.png",
@@ -84,7 +83,6 @@ frames = [
 
 [sprite."particle::explosion::tiny"]
 timing.fps = 15
-repeat = "once"
 frames = [
 	"particle/explosion-tiny/01.png",
 	"particle/explosion-tiny/02.png",
@@ -96,7 +94,6 @@ frames = [
 
 [sprite."particle::explosion::small"]
 timing.fps = 15
-repeat = "once"
 frames = [
 	"particle/explosion-small/01.png",
 	"particle/explosion-small/02.png",
@@ -109,7 +106,6 @@ frames = [
 
 [sprite."particle::explosion::medium"]
 timing.fps = 15
-repeat = "once"
 frames = [
 	"particle/explosion-medium/01.png",
 	"particle/explosion-medium/02.png",
@@ -124,7 +120,6 @@ frames = [
 
 [sprite."particle::explosion::large"]
 timing.fps = 15
-repeat = "once"
 frames = [
 	"particle/explosion-large/01.png",
 	"particle/explosion-large/02.png",
@@ -139,7 +134,6 @@ frames = [
 
 [sprite."particle::explosion::huge"]
 timing.fps = 15
-repeat = "once"
 frames = [
 	"particle/explosion-huge/01.png",
 	"particle/explosion-huge/02.png",
@@ -156,9 +150,8 @@ frames = [
 
 [sprite."particle::spark::blue"]
 timing.duration = 0.3
-#timing.rng = 0.2 # each frame will be independently sped up/slowed by this factor
-#timing.uniform_rng = 0.2 # one factor for all frames
-repeat = "reverse"
+top = "reverse"
+bot = "reverse"
 frames = [
 	"particle/spark-blue/01.png",
 	"particle/spark-blue/02.png",
@@ -170,7 +163,6 @@ frames = [
 [sprite."particle::spark::yellow"]
 timing.duration = 0.3
 timing.rng = 0.2
-repeat = "once"
 frames = [
 	"particle/spark-yellow/01.png",
 	"particle/spark-yellow/02.png",
@@ -182,7 +174,6 @@ frames = [
 [sprite."particle::spark::red"]
 timing.duration = 0.3
 timing.rng = 0.2
-repeat = "once"
 frames = [
 	"particle/spark-red/01.png",
 	"particle/spark-red/02.png",

crates/content/src/animautomaton.rs

@@ -0,0 +1,234 @@
+use crate::{AnimSectionHandle, Content, SectionEdge, SpriteHandle};
+
+/// A single frame's state
+#[derive(Debug, Clone)]
+pub struct SpriteAnimationFrame {
+	/// The index of the texture we're fading from
+	pub texture_a: u32,
+
+	/// The index of the texture we're fading to
+	pub texture_b: u32,
+
+	/// Between 0.0 and 1.0, denoting how far we are between
+	/// texture_a and texture_b
+	/// 0.0 means fully show texture_a;
+	/// 1.0 means fully show texture_b.
+	pub fade: f32,
+}
+
+impl SpriteAnimationFrame {
+	/// Convenience method.
+	/// Get texture index as an array
+	pub fn texture_index(&self) -> [u32; 2] {
+		[self.texture_a, self.texture_b]
+	}
+}
+
+/// What direction are we playing our animation in?
+#[derive(Debug, Clone)]
+enum AnimDirection {
+	/// Top to bottom, with increasing frame indices
+	/// (normal)
+	Up,
+
+	/// Bottom to top, with decreasing frame indices
+	/// (reverse)
+	Down,
+
+	/// Stopped, no animation
+	Stop,
+}
+
+/// Manages a single sprite's animation state.
+#[derive(Debug, Clone)]
+pub struct AnimAutomaton {
+	/// The sprite we're animating
+	sprite: SpriteHandle,
+
+	/// Which animation section we're on
+	/// This MUST be a section from this Automaton's sprite
+	current_section: AnimSectionHandle,
+
+	/// Which frame we're on
+	current_frame: usize,
+
+	/// Where we are between frames.
+	/// Always between zero and one.
+	current_fade: f32,
+
+	/// In what direction are we playing the current section?
+	current_direction: AnimDirection,
+
+	/// The texture we're fading from
+	/// (if we're moving downwards)
+	last_texture: u32,
+
+	/// The texture we're fading to
+	/// (if we're moving downwards)
+	next_texture: u32,
+}
+
+impl AnimAutomaton {
+	/// Create a new AnimAutomaton
+	pub fn new(ct: &Content, sprite_handle: SpriteHandle) -> Self {
+		let sprite = ct.get_sprite(sprite_handle);
+		Self {
+			current_direction: AnimDirection::Down,
+			sprite: sprite.handle,
+			current_frame: 0,
+			current_fade: 0.0,
+			current_section: sprite.default_section,
+
+			last_texture: *sprite
+				.get_section(sprite.default_section)
+				.frames
+				.first()
+				.unwrap(),
+
+			next_texture: *sprite
+				.get_section(sprite.default_section)
+				.frames
+				.first()
+				.unwrap(),
+		}
+	}
+
+	/// Reset this animation
+	pub fn reset(&mut self, ct: &Content) {
+		let sprite = ct.get_sprite(self.sprite);
+		self.current_fade = 0.0;
+		self.current_frame = 0;
+		self.current_section = sprite.default_section
+	}
+
+	/// Reverse this animation's direction
+	pub fn reverse(&mut self) {
+		match self.current_direction {
+			AnimDirection::Stop => {}
+			AnimDirection::Up => {
+				self.current_direction = AnimDirection::Down;
+			}
+			AnimDirection::Down => {
+				self.current_direction = AnimDirection::Up;
+			}
+		}
+	}
+
+	/// Step this animation by `t` seconds
+	pub fn step(&mut self, ct: &Content, t: f32) {
+		let sprite = ct.get_sprite(self.sprite);
+		let current_section = sprite.get_section(self.current_section);
+
+		// Current_fade and current_frame keep track of where we are in the current section.
+		// current_frame indexes this section frames. When it exceeds the number of frames
+		// or falls below zero (when moving in reverse), we switch to the next section.
+		//
+		// current_fade keeps track of our state between frames. It is zero once a frame starts,
+		// and we switch to the next frame when it hits 1.0. If we are stepping foward, it increases,
+		// and if we are stepping backwards, it decreases.
+
+		// If this is zero, this section isn't animated.
+		if current_section.frame_duration == 0.0 {
+			return;
+		}
+
+		match self.current_direction {
+			AnimDirection::Down => self.current_fade += t / current_section.frame_duration,
+			AnimDirection::Up => self.current_fade -= t / current_section.frame_duration,
+			AnimDirection::Stop => {}
+		}
+
+		// We're stepping foward and finished this frame
+		// (implies we're travelling downwards)
+		if self.current_fade > 1.0 {
+			while self.current_fade > 1.0 {
+				self.current_fade -= 1.0;
+			}
+
+			if self.current_frame < current_section.frames.len() - 1 {
+				self.current_frame += 1;
+			} else {
+				match current_section.edge_bot {
+					SectionEdge::Stop => {
+						self.current_fade = 0.0;
+						self.current_frame = current_section.frames.len() - 1;
+						self.current_direction = AnimDirection::Stop;
+					}
+					SectionEdge::Top { section } => {
+						self.current_section = section;
+						self.current_frame = 0;
+					}
+					SectionEdge::Bot { section } => {
+						let s = sprite.get_section(section);
+						self.current_section = section;
+						self.current_frame = s.frames.len() - 1;
+						self.reverse();
+					}
+					SectionEdge::Restart => {
+						self.current_frame = 0;
+					}
+					SectionEdge::Reverse => {
+						// Jump to SECOND frame, since we've already shown the
+						// first during the fade transition
+						self.current_frame = current_section.frames.len() - 1;
+						self.reverse()
+					}
+				}
+			}
+
+			let current_section = sprite.get_section(self.current_section);
+			self.last_texture = self.next_texture;
+			self.next_texture = current_section.frames[self.current_frame];
+		}
+
+		// We're stepping backward and finished this frame
+		// (implies we're travelling upwards)
+		if self.current_fade < 0.0 {
+			while self.current_fade < 0.0 {
+				self.current_fade += 1.0;
+			}
+
+			if self.current_frame > 0 {
+				self.current_frame -= 1;
+			} else {
+				match current_section.edge_top {
+					SectionEdge::Stop => {
+						self.current_fade = 0.0;
+						self.current_frame = 0;
+						self.current_direction = AnimDirection::Stop;
+					}
+					SectionEdge::Top { section } => {
+						self.current_section = section;
+						self.current_frame = 0;
+						self.reverse();
+					}
+					SectionEdge::Bot { section } => {
+						let s = sprite.get_section(section);
+						self.current_section = section;
+						self.current_frame = s.frames.len() - 1;
+					}
+					SectionEdge::Reverse => {
+						self.current_frame = 0;
+						self.reverse();
+					}
+					SectionEdge::Restart => {
+						self.current_frame = current_section.frames.len() - 1;
+					}
+				}
+			}
+
+			let current_section = sprite.get_section(self.current_section);
+			self.next_texture = self.last_texture;
+			self.last_texture = current_section.frames[self.current_frame];
+		}
+	}
+
+	/// Get the current frame of this animation
+	pub fn get_texture_idx(&self) -> SpriteAnimationFrame {
+		return SpriteAnimationFrame {
+			texture_a: self.last_texture,
+			texture_b: self.next_texture,
+			fade: self.current_fade,
+		};
+	}
+}

crates/content/src/handle.rs

@@ -16,14 +16,6 @@ pub struct SpriteHandle {
 	pub aspect: f32,
 }
 
-impl SpriteHandle {
-	/// The index of this sprite in content's sprite array.
-	/// Render uses this to build its buffers.
-	pub fn get_index(&self) -> u32 {
-		self.index as u32
-	}
-}
-
 impl Hash for SpriteHandle {
 	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 		self.index.hash(state)

crates/content/src/lib.rs

@@ -3,6 +3,7 @@
 //! This subcrate is responsible for loading, parsing, validating game content,
 //! which is usually stored in `./content`.
 
+mod animautomaton;
 mod handle;
 mod part;
 mod util;
@@ -18,6 +19,7 @@ use std::{
 use toml;
 use walkdir::WalkDir;
 
+pub use animautomaton::*;
 pub use handle::*;
 pub use part::*;
 
@@ -279,11 +281,13 @@ impl Content {
 	}
 
 	/// Get the handle for the starfield sprite
-	pub fn get_starfield_handle(&self) -> SpriteHandle {
-		match self.starfield_handle {
+	pub fn get_starfield_texture(&self) -> u32 {
+		let h = match self.starfield_handle {
 			Some(h) => h,
 			None => unreachable!("Starfield sprite hasn't been loaded yet!"),
-		}
+		};
+		let sprite = self.get_sprite(h);
+		sprite.get_section(sprite.default_section).frames[0]
 	}
 
 	/// Get a handle from a sprite name
@@ -306,9 +310,9 @@ impl Content {
 		return &self.sprite_atlas.atlas_list;
 	}
 
-	/// Get a sprite from a path
-	pub fn get_image(&self, p: &Path) -> &SpriteAtlasImage {
-		self.sprite_atlas.index.get(p).unwrap()
+	/// Get a texture by its index
+	pub fn get_image(&self, idx: u32) -> &SpriteAtlasImage {
+		&self.sprite_atlas.index[idx as usize]
 	}
 
 	/// Get an outfit from a handle

crates/content/src/part/effect.rs

@@ -57,7 +57,8 @@ pub(crate) mod syntax {
 				TextOrFloat::Text(s) => {
 					if s == "inherit" {
 						let sprite = content.get_sprite(sprite);
-						sprite.frame_duration * sprite.frames.len() as f32
+						let sec = sprite.get_section(sprite.default_section);
+						sec.frame_duration * sec.frames.len() as f32
 					} else {
 						bail!("bad effect lifetime, must be float or \"inherit\"",)
 					}

crates/content/src/part/mod.rs

@@ -18,5 +18,5 @@ pub use ship::{
 	CollapseEffectSpawner, CollapseEvent, EffectCollapseEvent, EnginePoint, GunPoint, Ship,
 	ShipCollapse,
 };
-pub use sprite::{RepeatMode, Sprite};
+pub use sprite::*;
 pub use system::{System, SystemObject};

crates/content/src/part/sprite.rs

@@ -1,44 +1,36 @@
-use anyhow::{bail, Context, Result};
-use image::io::Reader;
-use serde::Deserialize;
-use std::{collections::HashMap, path::PathBuf};
+use anyhow::{anyhow, bail, Context, Result};
+use std::collections::HashMap;
 
 use crate::{handle::SpriteHandle, Content, ContentBuildContext};
 
 pub(crate) mod syntax {
+	use crate::{Content, ContentBuildContext};
+	use anyhow::{anyhow, bail, Context, Ok, Result};
 	use serde::Deserialize;
-	use std::path::PathBuf;
+	use std::{collections::HashMap, path::PathBuf};
 
-	use super::RepeatMode;
+	use super::AnimSectionHandle;
 
 	// Raw serde syntax structs.
 	// These are never seen by code outside this crate.
 
+	/// Convenience variants of sprite definitions
 	#[derive(Debug, Deserialize)]
 	#[serde(untagged)]
 	pub enum Sprite {
 		Static(StaticSprite),
-		Frames(FrameSprite),
-	}
-
-	#[derive(Debug, Deserialize)]
-	pub struct StaticSprite {
-		pub file: PathBuf,
-	}
-
-	#[derive(Debug, Deserialize)]
-	pub struct FrameSprite {
-		pub frames: Vec<PathBuf>,
-		pub timing: Timing,
-		pub repeat: RepeatMode,
-		pub random_start_frame: Option<bool>,
+		OneSection(SpriteSection),
+		Complete(CompleteSprite),
 	}
 
+	/// Two ways to specify animation length
 	#[derive(Debug, Deserialize)]
 	pub enum TimingVariant {
+		/// The duration of this whole section
 		#[serde(rename = "duration")]
 		Duration(f32),
 
+		/// The fps of this section
 		#[serde(rename = "fps")]
 		Fps(f32),
 	}
@@ -47,36 +39,176 @@ pub(crate) mod syntax {
 	pub struct Timing {
 		#[serde(flatten)]
 		pub variant: TimingVariant,
-		//pub uniform_rng: Option<f32>,
+	}
+
+	/// An unanimated sprite
+	#[derive(Debug, Deserialize)]
+	pub struct StaticSprite {
+		pub file: PathBuf,
+	}
+
+	/// The proper, full sprite definition
+	#[derive(Debug, Deserialize)]
+	pub struct CompleteSprite {
+		pub section: HashMap<String, SpriteSection>,
+		pub default_section: String,
+	}
+
+	/// A single animation section
+	#[derive(Debug, Deserialize)]
+	pub struct SpriteSection {
+		pub frames: Vec<PathBuf>,
+		pub timing: Timing,
+		pub top: Option<SectionEdge>,
+		pub bot: Option<SectionEdge>,
+	}
+
+	impl SpriteSection {
+		pub fn add_to(
+			&self,
+			_build_context: &mut ContentBuildContext,
+			content: &mut Content,
+
+			// An index of all sections in this sprite, used to resolve
+			// top and bot edges.
+			all_sections: &HashMap<String, AnimSectionHandle>,
+		) -> Result<((u32, u32), super::SpriteSection)> {
+			// Make sure all frames have the same size and add them
+			// to the frame vector
+			let mut dim = None;
+			let mut frames = Vec::new();
+			for f in &self.frames {
+				let idx = match content.sprite_atlas.path_map.get(f) {
+					Some(s) => *s,
+					None => {
+						bail!("error: file `{}` isn't in the sprite atlas", f.display());
+					}
+				};
+				let img = &content.sprite_atlas.index[idx as usize];
+
+				match dim {
+					None => dim = Some(img.true_size),
+					Some(e) => {
+						if img.true_size != e {
+							bail!("failed to load section frames because frames have different sizes.",)
+						}
 					}
 				}
 
-/// How to replay a texture's animation
-#[derive(Debug, Deserialize, Clone, Copy)]
-pub enum RepeatMode {
-	/// Play this animation once, and stop at the last frame
-	#[serde(rename = "once")]
-	Once,
+				frames.push(img.idx);
+			}
+			let dim = dim.unwrap();
 
-	/// After the first frame, jump to the last frame
-	#[serde(rename = "repeat")]
-	Repeat,
+			let frame_duration = match self.timing.variant {
+				TimingVariant::Duration(d) => d / self.frames.len() as f32,
+				TimingVariant::Fps(f) => 1.0 / f,
+			};
 
-	/// Play this animation in reverse after the last frame
-	#[serde(rename = "reverse")]
+			if frame_duration <= 0.0 {
+				bail!("frame duration must be positive (and therefore nonzero).")
+			}
+
+			let edge_top = match &self.top {
+				Some(x) => x.resolve(all_sections)?,
+				None => super::SectionEdge::Stop,
+			};
+
+			let edge_bot = match &self.bot {
+				Some(x) => x.resolve(all_sections)?,
+				None => super::SectionEdge::Stop,
+			};
+
+			return Ok((
+				dim,
+				super::SpriteSection {
+					frames,
+					frame_duration,
+					edge_top,
+					edge_bot,
+				},
+			));
+		}
+	}
+
+	/// A link between two animation sections
+	#[derive(Debug, Deserialize)]
+	#[serde(transparent)]
+	pub struct SectionEdge {
+		pub val: String,
+	}
+
+	impl SectionEdge {
+		pub fn resolve(
+			&self,
+			all_sections: &HashMap<String, AnimSectionHandle>,
+		) -> Result<super::SectionEdge> {
+			if self.val == "stop" {
+				return Ok(super::SectionEdge::Stop);
+			}
+
+			if self.val == "reverse" {
+				return Ok(super::SectionEdge::Reverse);
+			}
+
+			if self.val == "restart" {
+				return Ok(super::SectionEdge::Restart);
+			}
+
+			let (s, p) = match self.val.split_once(":") {
+				Some(x) => x,
+				None => {
+					bail!("bad section edge specification `{}`", self.val);
+				}
+			};
+
+			let section = match all_sections.get(s) {
+				Some(s) => *s,
+				None => {
+					return Err(anyhow!("bad section edge specification `{}`", self.val))
+						.with_context(|| format!("section `{}` doesn't exist", s));
+				}
+			};
+
+			match p {
+				"top" => Ok(super::SectionEdge::Top { section }),
+				"bot" => Ok(super::SectionEdge::Bot { section }),
+				_ => {
+					return Err(anyhow!("bad section edge specification `{}`", self.val))
+						.with_context(|| format!("invalid target `{}`", p));
+				}
+			}
+		}
+	}
+}
+
+// TODO: should be pub crate
+/// A handle for an animation section inside a sprite
+#[derive(Debug, Copy, Clone)]
+pub struct AnimSectionHandle(usize);
+
+/// An edge between two animation sections
+#[derive(Debug, Clone)]
+pub enum SectionEdge {
+	/// Stop at the last frame of this section
+	Stop,
+
+	/// Play the given section from the bottm
+	Bot {
+		/// The section to play
+		section: AnimSectionHandle,
+	},
+
+	/// Play the given section from the top
+	Top {
+		/// The section to play
+		section: AnimSectionHandle,
+	},
+
+	/// Replay this section in the opposite direction
 	Reverse,
-}
 
-impl RepeatMode {
-	/// Represent this repeatmode as an integer
-	/// Used to pass this enum into shaders
-	pub fn as_int(&self) -> u32 {
-		match self {
-			Self::Repeat => 0,
-			Self::Once => 1,
-			Self::Reverse => 2,
-		}
-	}
+	/// Restart this section from the opposite end
+	Restart,
 }
 
 /// Represents a sprite that may be used in the game.
@@ -88,25 +220,44 @@ pub struct Sprite {
 	/// This sprite's handle
 	pub handle: SpriteHandle,
 
-	/// The file names of frames of this sprite.
-	/// unanimated sprites have one frame.
-	pub frames: Vec<PathBuf>,
+	/// This sprite's default section
+	pub default_section: AnimSectionHandle,
 
-	/// The speed of this sprite's animation.
-	/// This is zero for unanimate sprites.
-	pub frame_duration: f32,
-
-	/// All frames will be sped up/slowed by this factor.
-	//pub frame_uniform_rng: f32,
-
-	/// How to replay this sprite's animation
-	pub repeat: RepeatMode,
+	/// This sprite's animation sections
+	sections: Vec<SpriteSection>,
 
 	/// Aspect ratio of this sprite (width / height)
 	pub aspect: f32,
+}
 
-	/// If true, start on a random frame of this sprite.
-	pub random_start_frame: bool,
+impl Sprite {
+	/// Get an animation section from a handle
+	pub fn get_section(&self, section: AnimSectionHandle) -> &SpriteSection {
+		&self.sections[section.0]
+	}
+
+	/// Iterate this sprite's sections
+	pub fn iter_sections(&self) -> impl Iterator<Item = &SpriteSection> {
+		self.sections.iter()
+	}
+}
+
+/// A part of a sprite's animation
+#[derive(Debug, Clone)]
+pub struct SpriteSection {
+	/// The texture index of each frame in this animation section.
+	/// unanimated sections have one frame.
+	pub frames: Vec<u32>,
+
+	/// The speed of this sprite's animation.
+	/// This must always be positive (and therefore, nonzero)
+	pub frame_duration: f32,
+
+	/// What to do when we reach the top of this section
+	pub edge_top: SectionEdge,
+
+	/// What to do when we reach the bottom of this section
+	pub edge_bot: SectionEdge,
 }
 
 impl crate::Build for Sprite {
@@ -114,31 +265,32 @@ impl crate::Build for Sprite {
 
 	fn build(
 		sprites: Self::InputSyntaxType,
-		_build_context: &mut ContentBuildContext,
+		build_context: &mut ContentBuildContext,
 		content: &mut Content,
 	) -> Result<()> {
 		for (sprite_name, t) in sprites {
 			match t {
 				syntax::Sprite::Static(t) => {
-					let file = content.config.sprite_root.join(&t.file);
-					let reader = Reader::open(&file).with_context(|| {
-						format!(
-							"Failed to read file `{}` in sprite `{}`",
-							file.display(),
-							sprite_name,
+					let idx = match content.sprite_atlas.path_map.get(&t.file) {
+						Some(s) => *s,
+						None => {
+							return Err(
+								anyhow!("error while processing sprite `{}`", sprite_name,),
 							)
-					})?;
-					let dim = reader.into_dimensions().with_context(|| {
+							.with_context(|| {
 								format!(
-							"Failed to get dimensions of file `{}` in sprite `{}`",
-							file.display(),
-							sprite_name,
+									"file `{}` isn't in the sprite atlas, cannot proceed",
+									t.file.display()
 								)
-					})?;
+							});
+						}
+					};
+					let img = &content.sprite_atlas.index[idx as usize];
+					let aspect = img.w / img.h;
 
 					let h = SpriteHandle {
 						index: content.sprites.len(),
-						aspect: dim.0 as f32 / dim.1 as f32,
+						aspect,
 					};
 
 					if sprite_name == content.config.starfield_sprite {
@@ -154,71 +306,108 @@ impl crate::Build for Sprite {
 
 					content.sprites.push(Self {
 						name: sprite_name,
-						frames: vec![t.file],
-						frame_duration: 0.0,
-						//frame_uniform_rng: 0.0,
+						default_section: AnimSectionHandle(0),
+						sections: vec![SpriteSection {
+							frames: vec![img.idx],
+							// We implement unanimated sprites with a very fast framerate
+							// and STOP endpoints.
+							frame_duration: 0.01,
+							edge_top: SectionEdge::Stop,
+							edge_bot: SectionEdge::Stop,
+						}],
 						handle: h,
-						repeat: RepeatMode::Once,
-						aspect: dim.0 as f32 / dim.1 as f32,
-						random_start_frame: false,
+						aspect,
 					});
 				}
-				syntax::Sprite::Frames(t) => {
-					let mut dim = None;
-					for f in &t.frames {
-						let file = content.config.sprite_root.join(f);
-						let reader = Reader::open(&file).with_context(|| {
-							format!(
-								"Failed to read file `{}` in sprite `{}`",
-								file.display(),
-								sprite_name,
-							)
-						})?;
-						let d = reader.into_dimensions().with_context(|| {
-							format!(
-								"Failed to get dimensions of file `{}` in sprite `{}`",
-								file.display(),
-								sprite_name,
-							)
-						})?;
-						match dim {
-							None => dim = Some(d),
-							Some(e) => {
-								if d != e {
-									bail!(
-										"Failed to load frames of sprite `{}` because frames have different sizes.",
-										sprite_name,
-									)
-								}
-							}
-						}
-					}
-					let dim = dim.unwrap();
+				syntax::Sprite::OneSection(s) => {
+					let mut section_names: HashMap<String, _> = HashMap::new();
+					// Name the one section in this sprite "anim"
+					section_names.insert("anim".to_owned(), AnimSectionHandle(0));
 
+					let (dim, section) = s
+						.add_to(build_context, content, &section_names)
+						.with_context(|| format!("while parsing sprite `{}`", sprite_name))?;
+					let aspect = dim.0 as f32 / dim.1 as f32;
 					let h = SpriteHandle {
 						index: content.sprites.len(),
-						aspect: dim.0 as f32 / dim.1 as f32,
+						aspect,
 					};
 
+					// TODO: remove?
 					if sprite_name == content.config.starfield_sprite {
 						unreachable!("Starfield texture may not be animated")
 					}
 
-					let frame_duration = match t.timing.variant {
-						syntax::TimingVariant::Duration(d) => d / t.frames.len() as f32,
-						syntax::TimingVariant::Fps(f) => 1.0 / f,
+					let mut sections = Vec::new();
+					sections.push(section);
+
+					content.sprite_index.insert(sprite_name.clone(), h);
+					content.sprites.push(Self {
+						name: sprite_name,
+						sections,
+						default_section: AnimSectionHandle(0),
+						handle: h,
+						aspect,
+					});
+				}
+				syntax::Sprite::Complete(s) => {
+					let mut idx = 0;
+					let mut section_names = HashMap::new();
+					for (name, _) in &s.section {
+						section_names.insert(name.to_owned(), AnimSectionHandle(idx));
+						idx += 1;
+					}
+
+					if !section_names.contains_key(&s.default_section) {
+						bail!(
+							"could not load sprite `{}`, default section `{}` doesn't exist",
+							sprite_name,
+							s.default_section
+						);
+					}
+
+					let mut sections = Vec::with_capacity(idx);
+					let mut dim = None;
+
+					// Make sure we add sections in order
+					let mut names = section_names.iter().collect::<Vec<_>>();
+					names.sort_by(|a, b| (a.1).0.cmp(&(b.1).0));
+
+					for (k, _) in names {
+						let v = s.section.get(k).unwrap();
+						let (d, s) = v
+							.add_to(build_context, content, &section_names)
+							.with_context(|| format!("while parsing sprite `{}`", sprite_name))
+							.with_context(|| format!("while parsing section `{}`", k))?;
+
+						// Make sure all dimensions are the same
+						if dim.is_none() {
+							dim = Some(d);
+						} else if dim.unwrap() != d {
+							bail!(
+								"could not load sprite `{}`, image sizes in section `{}` are different",
+								sprite_name,
+								k
+							);
+						}
+
+						sections.push(s);
+					}
+					let dim = dim.unwrap();
+					let aspect = dim.0 as f32 / dim.1 as f32;
+
+					let h = SpriteHandle {
+						index: content.sprites.len(),
+						aspect,
 					};
 
 					content.sprite_index.insert(sprite_name.clone(), h);
 					content.sprites.push(Self {
 						name: sprite_name,
-						frames: t.frames,
-						frame_duration,
-						//frame_uniform_rng: t.timing.uniform_rng.unwrap_or(0.0),
+						sections,
+						default_section: *section_names.get(&s.default_section).unwrap(),
 						handle: h,
-						repeat: t.repeat,
-						aspect: dim.0 as f32 / dim.1 as f32,
-						random_start_frame: t.random_start_frame.unwrap_or(false),
+						aspect,
 					});
 				}
 			}