refactor: split up and move texture-related code into src/texture submodule

src/texture/atlas.rs

@@ -0,0 +1,67 @@
+use sdl2::{
+    rect::Rect,
+    render::{Canvas, Texture},
+    video::Window,
+};
+
+use crate::{direction::Direction, texture::FrameDrawn};
+
+/// A texture atlas abstraction for static (non-animated) rendering.
+pub struct AtlasTexture<'a> {
+    pub raw_texture: Texture<'a>,
+    pub offset: (i32, i32),
+    pub frame_count: u32,
+    pub frame_width: u32,
+    pub frame_height: u32,
+}
+
+impl<'a> AtlasTexture<'a> {
+    pub fn new(texture: Texture<'a>, frame_count: u32, frame_width: u32, frame_height: u32, offset: Option<(i32, i32)>) -> Self {
+        AtlasTexture {
+            raw_texture: texture,
+            frame_count,
+            frame_width,
+            frame_height,
+            offset: offset.unwrap_or((0, 0)),
+        }
+    }
+
+    pub fn get_frame_rect(&self, frame: u32) -> Option<Rect> {
+        if frame >= self.frame_count {
+            return None;
+        }
+        Some(Rect::new(
+            frame as i32 * self.frame_width as i32,
+            0,
+            self.frame_width,
+            self.frame_height,
+        ))
+    }
+
+    pub fn set_color_modulation(&mut self, r: u8, g: u8, b: u8) {
+        self.raw_texture.set_color_mod(r, g, b);
+    }
+}
+
+impl<'a> FrameDrawn for AtlasTexture<'a> {
+    fn render(&self, canvas: &mut Canvas<Window>, position: (i32, i32), direction: Direction, frame: Option<u32>) {
+        let texture_source_frame_rect = self.get_frame_rect(frame.unwrap_or(0));
+        let canvas_destination_rect = Rect::new(
+            position.0 + self.offset.0,
+            position.1 + self.offset.1,
+            self.frame_width,
+            self.frame_height,
+        );
+        canvas
+            .copy_ex(
+                &self.raw_texture,
+                texture_source_frame_rect,
+                Some(canvas_destination_rect),
+                direction.angle(),
+                None,
+                false,
+                false,
+            )
+            .expect("Could not render texture on canvas");
+    }
+}