refactor query into yielding api

server/components/display.ts

@@ -1,6 +1,25 @@
+import { v2 } from "../../common/utils.ts";
+import { range, Vec2 } from "../../common/utils.ts";
+import { Engine } from "../engine.ts";
+import { query_in_rect } from "./world.ts";
+
 export class CompDisplay {
 	display;
 	constructor(display: string) {
 		this.display = display;
 	}
 }
+
+export function sys_render_world(center: Vec2, size: Vec2) {
+	return (engine: Engine) => {
+		const radius = size.scale(0.5);
+		const result = Array.from(range(0, size.y())).map(() => Array.from(range(0, size.x())).map(() => "  "));
+		const min = center.sub(radius);
+		const max = center.add(radius).sub(v2(1, 1));
+		for (const [pos, display] of engine.query_all(query_in_rect(min, max).with(CompDisplay))) {
+			const local_pos = pos.position.sub(min);
+			result[local_pos.y()][local_pos.x()] = display.display;
+		}
+		return result.map((line) => line.join("")).toReversed().join("\n");
+	};
+}