a bit of refactoring; importing engine into bun for server

1 files changed, 92 insertions, 0 deletions

diff --git a/engine/components/Sprite.ts b/engine/components/Sprite.ts
new file mode 100644
index 0000000..90e1389
--- /dev/null
+++ b/engine/components/Sprite.ts
@@ -0,0 +1,92 @@
+import { Component, ComponentNames } from ".";
+import type { Dimension2D, DrawArgs, Coord2D } from "../interfaces";
+
+export class Sprite extends Component {
+  private sheet: HTMLImageElement;
+
+  private spriteImgPos: Coord2D;
+  private spriteImgDimensions: Dimension2D;
+
+  private msPerFrame: number;
+  private msSinceLastFrame: number;
+  private currentFrame: number;
+  private numFrames: number;
+
+  constructor(
+    sheet: HTMLImageElement,
+    spriteImgPos: Coord2D,
+    spriteImgDimensions: Dimension2D,
+    msPerFrame: number,
+    numFrames: number
+  ) {
+    super(ComponentNames.Sprite);
+
+    this.sheet = sheet;
+    this.spriteImgPos = spriteImgPos;
+    this.spriteImgDimensions = spriteImgDimensions;
+    this.msPerFrame = msPerFrame;
+    this.numFrames = numFrames;
+
+    this.msSinceLastFrame = 0;
+    this.currentFrame = 0;
+  }
+
+  public update(dt: number) {
+    this.msSinceLastFrame += dt;
+    if (this.msSinceLastFrame >= this.msPerFrame) {
+      this.currentFrame = (this.currentFrame + 1) % this.numFrames;
+      this.msSinceLastFrame = 0;
+    }
+  }
+
+  public draw(ctx: CanvasRenderingContext2D, drawArgs: DrawArgs) {
+    const { center, rotation, tint, opacity } = drawArgs;
+
+    ctx.save();
+    ctx.translate(center.x, center.y);
+    if (rotation != 0) {
+      ctx.rotate(rotation * (Math.PI / 180));
+    }
+    ctx.translate(-center.x, -center.y);
+
+    if (opacity) {
+      ctx.globalAlpha = opacity;
+    }
+
+    ctx.drawImage(
+      this.sheet,
+      ...this.getSpriteArgs(),
+      ...this.getDrawArgs(drawArgs)
+    );
+
+    if (tint) {
+      ctx.globalAlpha = 0.5;
+      ctx.globalCompositeOperation = "source-atop";
+      ctx.fillStyle = tint;
+      ctx.fillRect(...this.getDrawArgs(drawArgs));
+    }
+
+    ctx.restore();
+  }
+
+  private getSpriteArgs(): [sx: number, sy: number, sw: number, sh: number] {
+    return [
+      this.spriteImgPos.x + this.currentFrame * this.spriteImgDimensions.width,
+      this.spriteImgPos.y,
+      this.spriteImgDimensions.width,
+      this.spriteImgDimensions.height,
+    ];
+  }
+
+  private getDrawArgs({
+    center,
+    dimension,
+  }: DrawArgs): [dx: number, dy: number, dw: number, dh: number] {
+    return [
+      center.x - dimension.width / 2,
+      center.y - dimension.height / 2,
+      dimension.width,
+      dimension.height,
+    ];
+  }
+}