Non-grid-based movement

src/engine/datatypes.ts

@@ -84,6 +84,13 @@ export class Point {
     return new Point(this.x * other.w, this.y * other.h);
   }
 
+  unscale(other: Point | Size) {
+    if (other instanceof Point) {
+      return new Point(this.x / other.x, this.y / other.y);
+    }
+    return new Point(this.x / other.w, this.y / other.h);
+  }
+
   subtract(top: Point): Size {
     return new Size(this.x - top.x, this.y - top.y);
   }
@@ -91,6 +98,13 @@ export class Point {
   manhattan(other: Point) {
     return Math.abs(this.x - other.x) + Math.abs(this.y - other.y);
   }
+
+  snap(x: number, y: number) {
+    return new Point(
+      lerp(x, Math.floor(this.x), Math.ceil(this.x)),
+      lerp(y, Math.floor(this.y), Math.ceil(this.y))
+    );
+  }
 }
 
 export class Size {
@@ -118,12 +132,16 @@ export class Size {
 export class Rect {
   readonly top: Point;
   readonly size: Size;
-
   constructor(top: Point, size: Size) {
     this.top = top;
     this.size = size;
   }
 
+  toString(): string {
+    return `Rect(${this.top},${this.size})`;
+  }
+
+
   offset(offset: Point) {
     return new Rect(this.top.offset(offset), this.size);
   }
@@ -137,6 +155,28 @@ export class Rect {
     );
   }
 
+  overlappedCells(size: Size) {
+    let x0 = this.top.x;
+    let y0 = this.top.y;
+    let x1 = x0 + this.size.w;
+    let y1 = y0 + this.size.w;
+
+    let cx0 = Math.floor(x0 / size.w);
+    let cy0 = Math.floor(y0 / size.h);
+    let cx1 = Math.ceil(x1 / size.w);
+    let cy1 = Math.ceil(y1 / size.h);
+
+    let cells = [];
+    for (let cy = cy0; cy < cy1; cy++) {
+      for (let cx = cx0; cx < cx1; cx++) {
+        let px0 = cx * size.w;
+        let py0 = cy * size.h;
+        cells.push(new Rect(new Point(px0, py0), size));
+      }
+    }
+    return cells;
+  }
+
   overlaps(other: Rect) {
     let ax0 = this.top.x;
     let ay0 = this.top.y;
@@ -254,3 +294,13 @@ export enum AlignY {
   Middle = 1,
   Bottom = 2,
 }
+
+export function lerp(amt: number, lo: number, hi: number) {
+  if (amt <= 0) {
+    return lo;
+  }
+  if (amt >= 1) {
+    return hi;
+  }
+  return lo + (hi - lo) * amt;
+};