[game] Animation, looks bad

game/main.ts

@@ -4,6 +4,9 @@ import { since_start } from "./time";
 import { btn, Button } from "./input";
 import { new_v2, vadd, vmul, vnorm } from "./vector";
 
+/// A nice looping frame counter.
+let clock = 0;
+
 let bot_sprite: number | undefined = undefined;
 
 // Note zelda overworld is 16x8 screens
@@ -25,6 +28,8 @@ let robo_vel = new_v2(0);
 let robo_pos = new_v2(10);
 
 export function update() {
+  clock = (clock + 1) % 20160;
+
   // Acceleration from input
   let a = new_v2(0);
   if (btn(Button.Up)) {
@@ -40,11 +45,20 @@ export function update() {
     a.x += 1;
   }
   vnorm(a);
+  a = vmul(a, 0.4); // Speed.
 
   // Friction
   let v = vmul(robo_vel, friction);
   v = vadd(v, a);
 
+  // Zero if we're smaller than some epsilon.
+  if (Math.abs(v.x) < 0.01) {
+    v.x = 0;
+  }
+  if (Math.abs(v.y) < 0.01) {
+    v.y = 0;
+  }
+
   // Motion
   let np = vadd(robo_pos, v);
 
@@ -54,13 +68,26 @@ export function update() {
   robo_vel = v;
 }
 
+// GARBAGE OBVIOUSLY
+const robo_info = {
+  width: 32,
+  height: 32,
+  animations: [
+    { start: 0, length: 2, speed: 20 },
+    { start: 2, length: 8, speed: 8 },
+  ],
+};
+
 export function draw() {
   cls(0.1, 0.2, 0.3);
   if (bot_sprite != undefined) {
     // ...it gets resolved here?
     use_texture(bot_sprite);
 
-    spr(robo_pos.x, robo_pos.y, 32, 32, 0, 0, 32, 32);
+    const moving = robo_vel.x != 0 || robo_vel.y != 0;
+    const anim = robo_info.animations[moving ? 1 : 0];
+    const frame = (anim.start + ((clock / anim.speed) % anim.length)) >> 0;
+    spr(robo_pos.x, robo_pos.y, 32, 32, frame * robo_info.width, 0, 32, 32);
   }
   // print("FRAME TIME:", since_last_frame());
 }