Switch to renderer component

src/main.rs

 mod physics;
 mod animator;
 mod keyboard;
+mod renderer;
 
 use sdl2::pixels::Color;
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
-use sdl2::render::{WindowCanvas, Texture};
 use sdl2::rect::{Point, Rect};
 use sdl2::image::{self, LoadTexture, InitFlag};
 
 use specs::prelude::*;
-use specs_derive::Component;
 
 use std::time::Duration;
 
     return frames
 }
 
-fn render (
-    canvas: &mut WindowCanvas,
-    color: Color,
-    texture: &Texture,
-    player: &Player
-) -> Result<(), String> {
-    canvas.set_draw_color(color);
-    canvas.clear();
-
-    let (width, height) = canvas.output_size()?;
-
-    let (frame_width, frame_height) = player.sprite.size();
-    let current_frame = Rect::new(
-        player.sprite.x() + frame_width as i32 * player.current_frame,
-        player.sprite.y() + frame_height as i32 * direction_spritesheet_row(player.direction),
-        frame_width,
-        frame_height,
-    );
-
-    let screen_position = player.position + Point::new(width as i32 / 2, height as i32 / 2);
-    let screen_rect = Rect::from_center(screen_position, frame_width, frame_height);
-    canvas.copy(texture, current_frame, screen_rect)?;
-
-    canvas.present();
-
-    Ok(())
-}
-
-fn update_player(player: &mut Player) {
-    use self::Direction::*;
-    match player.direction {
-        Left => {
-            player.position = player.position.offset(-player.speed, 0);
-        },
-        Right => {
-            player.position = player.position.offset(player.speed, 0);
-        },
-        Up => {
-            player.position = player.position.offset(0, -player.speed);
-        },
-        Down => {
-            player.position = player.position.offset(0, player.speed);
-        }
-    }
-
-    if player.speed != 0 {
-        player.current_frame = (player.current_frame + 1) % 3;
-    }
-}
-
 fn main() -> Result<(), String> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
     let mut world = World::new();
     dispatcher.setup(&mut world.res);
+    renderer::SystemData::setup(&mut world.res);
 
     let movement_command: Option<MovementCommand> = None;
     world.add_resource(movement_command);
         dispatcher.dispatch(&mut world.res);
         world.maintain();
 
-        render(&mut canvas, Color::RGB(i, 64, 255 - i), &texture, &player)?;
+        renderer::render(&mut canvas, Color::RGB(i, 64, 255 - i), &textures, world.system_data())?;
 
         ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 20));
 

src/renderer.rs

+use specs::prelude::*;
+use sdl2::rect::{Point, Rect};
+use sdl2::pixels::Color;
+use sdl2::render::{WindowCanvas, Texture};
+
+use crate::components::*;
+
+pub type SystemData<'a> = (
+    ReadStorage<'a, Position>,
+    ReadStorage<'a, Sprite>,
+);
+
+pub fn render(
+    canvas: &mut WindowCanvas,
+    background: Color,
+    textures: &[Texture],
+    data: SystemData
+) -> Result<(), String> {
+    canvas.set_draw_color(background);
+    canvas.clear();
+
+    let (width, height) = canvas.output_size()?;
+
+    for (pos, sprite) in (&data.0, &data.1).join() {
+        let current_frame = sprite.region;
+
+        let screen_position = pos.0 + Point::new(width as i32 / 2, height as i32 / 2);
+        let screen_rect = Rect::from_center(screen_position, current_frame.width(), current_frame.height());
+        canvas.copy(&textures[sprite.spritesheet], current_frame, screen_rect)?;
+    }
+
+    canvas.present();
+
+    Ok(())
+}