time for a snapshot

workshop/steps/08-resolve/resolve.ts

@@ -0,0 +1,11 @@
+import { add, type Hit, scale, type Vec } from "./given.ts";
+
+/**
+ * The new position after this frame's move, stopping at a collision if there is
+ * one.
+ *   hit === null -> pos + v         (take the whole move)
+ *   hit          -> pos + v * time  (stop at the contact point)
+ */
+export function resolve(pos: Vec, v: Vec, hit: Hit | null): Vec {
+	return hit ? add(pos, scale(v, hit.time)) : add(pos, v);
+}