graphics: add text message rendering (and sans ig)

3 files changed, 103 insertions, 3 deletions

diff --git a/dungeon/src/lib.rs b/dungeon/src/lib.rs
index a475f95..0c9e055 100644
--- a/dungeon/src/lib.rs
+++ b/dungeon/src/lib.rs
@@ -5,6 +5,7 @@ pub mod astar;
 pub mod bsp;
 pub mod entity;
 pub mod map;
+pub mod msg;
 pub mod player_input;
 pub mod pos;
 
@@ -16,10 +17,23 @@ use rand::{
 use crate::{
 	entity::{Entity, Player},
 	map::Floor,
+	msg::Message,
 	player_input::PlayerInput,
 	pos::FPos,
 };
 
+/// Lets the caller know what has
+/// changed in the game state this
+/// tick
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum UpdateResult {
+	/// Default, entities have moved
+	EntityMovement,
+	/// Message on screen updated.
+	/// Contains if a char was added.
+	MessageUpdated(bool),
+}
+
 /// The `Dungeon` type represents the game state of the
 /// dungeon crawler.
 #[derive(Debug, Clone)]
@@ -27,6 +41,7 @@ pub struct Dungeon {
 	pub floor: Floor,
 	pub player: Player,
 	pub enemies: Vec<Entity>,
+	pub msg: Message,
 	seed: u64,
 	rng: SmallRng,
 }
@@ -48,11 +63,13 @@ impl Dungeon {
 		let player = Player::new(floor.player_start());
 		// TODO: Randomize enemy positions/types
 		let enemies = vec![Entity::zombie(floor.random_walkable_pos(&mut rng))];
+		let msg = Message::empty();
 
 		Self {
 			floor,
 			player,
 			enemies,
+			msg,
 			seed,
 			rng,
 		}
@@ -91,9 +108,15 @@ impl Dungeon {
 		&mut self.rng
 	}
 
-	pub fn update(&mut self, player_input: PlayerInput, delta_time: f32) {
-		self.act_player(player_input, delta_time);
-		self.act_non_players(delta_time);
+	pub fn update(&mut self, player_input: PlayerInput, delta_time: f32) -> UpdateResult {
+		if self.msg.visible() {
+			let changed = self.msg.update(player_input);
+			UpdateResult::MessageUpdated(changed)
+		} else {
+			self.act_player(player_input, delta_time);
+			self.act_non_players(delta_time);
+			UpdateResult::EntityMovement
+		}
 	}
 
 	fn act_player(&mut self, player_input: PlayerInput, delta_time: f32) {
diff --git a/dungeon/src/msg.rs b/dungeon/src/msg.rs
new file mode 100644
index 0000000..68a6cbd
--- /dev/null
+++ b/dungeon/src/msg.rs
@@ -0,0 +1,74 @@
+//! The `msg` crate contains the core functionality for
+//! the on screen message.
+
+use std::time::{Duration, Instant};
+
+use crate::player_input::PlayerInput;
+
+/// Duration between each character printed
+const DURATION_PER: Duration = Duration::from_millis(100);
+
+#[derive(Debug, Clone)]
+pub struct Message {
+	text: Option<Vec<u8>>,
+	end: usize,
+	waiting: bool,
+	last: Instant,
+}
+impl Message {
+	/// Returns the default empty message
+	pub fn empty() -> Self {
+		Self {
+			text: None,
+			end: 0,
+			waiting: false,
+			last: Instant::now(),
+		}
+	}
+
+	/// Sets string as the current onscreen message
+	pub fn set_message(&mut self, msg: &str) {
+		let bytes = msg.bytes().collect();
+		self.text = Some(bytes);
+		self.end = 0;
+	}
+
+	/// Attempts to update the message on screen.
+	/// Returns true if a character was printed
+	pub fn update(&mut self, input: PlayerInput) -> bool {
+		let Some(text) = &self.text else { return false };
+
+		if self.end >= text.len() {
+			if input.interact {
+				self.text = None;
+			}
+			return false;
+		}
+
+		if self.waiting && !input.interact {
+			return false;
+		}
+
+		if self.last.elapsed() < DURATION_PER {
+			return false;
+		}
+		self.last = Instant::now();
+
+		if text[self.end] == b'.' {
+			self.waiting = true;
+		}
+
+		self.end += 1;
+		true
+	}
+
+	/// Returns the current ascii message (if exists)
+	pub fn current(&self) -> Option<&[u8]> {
+		self.text.as_ref().map(|text| &text[..self.end])
+	}
+
+	/// Returns if the message box is visible
+	pub const fn visible(&self) -> bool {
+		self.text.is_some()
+	}
+}
diff --git a/dungeon/src/player_input.rs b/dungeon/src/player_input.rs
index aa0ef14..ddaad9f 100644
--- a/dungeon/src/player_input.rs
+++ b/dungeon/src/player_input.rs
@@ -12,5 +12,8 @@ pub struct PlayerInput {
 	/// (eg if the player is holding multiple keys at once,
 	///     or a joystick)
 	pub direction: Option<Direction>,
+	/// If the player is currently attempting to interact
+	/// with some object, entity, etc.
+	pub interact: bool,
 	// other player actions are to be added later
 }