46 lines
1.8 KiB
Rust
46 lines
1.8 KiB
Rust
use ggez::graphics::DrawParam;
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use ggez::graphics::Image;
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use ggez::nalgebra as na;
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use ggez::{graphics, Context};
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use specs::{Join, ReadStorage, System};
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use crate::components::{Position, Renderable};
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use crate::constants::TILE_WIDTH;
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pub struct RenderingSystem<'a> {
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pub context: &'a mut Context,
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}
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impl<'a> System<'a> for RenderingSystem<'a> {
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type SystemData = (ReadStorage<'a, Position>, ReadStorage<'a, Renderable>);
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fn run(&mut self, data: Self::SystemData) {
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let (positions, renderables) = data;
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// Clear the screen/set the background
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graphics::clear(self.context, graphics::Color::new(0.95, 0.95, 0.95, 1.0));
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// Get all the renderables with their positions and sort by the position z
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// This will allow us to have entities layered visually.
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let mut rendering_data = (&positions, &renderables).join().collect::<Vec<_>>();
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rendering_data.sort_by(|&a, &b| a.0.z.partial_cmp(&b.0.z).expect("expected comparison"));
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// Iterate through all paris of positions & renderables, load the image
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// and draw it at the specified position.
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for (position, renderable) in rendering_data.iter() {
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// Load the image
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let image = Image::new(self.context, renderable.path.clone()).expect("expected image");
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let x = position.x as f32 * TILE_WIDTH;
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let y = position.y as f32 * TILE_WIDTH;
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// draw
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let draw_params = DrawParam::new().dest(na::Point2::new(x, y));
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graphics::draw(self.context, &image, draw_params).expect("expected render");
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}
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// Finally, present the context, this will actually display everything
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// on the screen.
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graphics::present(self.context).expect("expected to present");
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}
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}
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