feat: atlas decoding & frame acquisition

src/texture/directional.rs

@@ -0,0 +1,52 @@
+//! A texture that changes based on the direction of an entity.
+use crate::entity::direction::Direction;
+use crate::texture::sprite::AtlasTile;
+use anyhow::Result;
+use glam::IVec2;
+use sdl2::render::WindowCanvas;
+
+pub struct DirectionalAnimatedTexture {
+    pub up: Vec<AtlasTile>,
+    pub down: Vec<AtlasTile>,
+    pub left: Vec<AtlasTile>,
+    pub right: Vec<AtlasTile>,
+    pub ticker: u32,
+    pub ticks_per_frame: u32,
+}
+
+impl DirectionalAnimatedTexture {
+    pub fn new(
+        up: Vec<AtlasTile>,
+        down: Vec<AtlasTile>,
+        left: Vec<AtlasTile>,
+        right: Vec<AtlasTile>,
+        ticks_per_frame: u32,
+    ) -> Self {
+        Self {
+            up,
+            down,
+            left,
+            right,
+            ticker: 0,
+            ticks_per_frame,
+        }
+    }
+
+    pub fn tick(&mut self) {
+        self.ticker += 1;
+    }
+
+    pub fn render(&mut self, canvas: &mut WindowCanvas, dest: sdl2::rect::Rect, direction: Direction) -> Result<()> {
+        let frames = match direction {
+            Direction::Up => &self.up,
+            Direction::Down => &self.down,
+            Direction::Left => &self.left,
+            Direction::Right => &self.right,
+        };
+
+        let frame_index = (self.ticker / self.ticks_per_frame) as usize % frames.len();
+        let tile = &frames[frame_index];
+
+        tile.render(canvas, dest)
+    }
+}