From 9472718f52ee849a587d0305daf50b8f4ea71094 Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Fri, 12 Mar 2021 18:00:41 -0700
Subject: [PATCH] ripple

---
 src/_posts/2021-03-12-ripple-a-game.md | 308 +++++++++++++++++++++++++
 1 file changed, 308 insertions(+)
 create mode 100644 src/_posts/2021-03-12-ripple-a-game.md

diff --git a/src/_posts/2021-03-12-ripple-a-game.md b/src/_posts/2021-03-12-ripple-a-game.md
new file mode 100644
index 0000000..5fea664
--- /dev/null
+++ b/src/_posts/2021-03-12-ripple-a-game.md
@@ -0,0 +1,308 @@
+---
+title: >-
+    Ripple: A Game
+description: >-
+    Hop Till You Drop!
+---
+
+<p>
+    <b>Movement:</b> Arrow keys or WASD<br/>
+    <b>Jump:</b> Space<br/>
+    <b>Goal:</b> Jump as many times as possible without touching a ripple!<br/>
+    <br/>
+    <b>Press Jump To Begin!</b>
+</p>
+
+<canvas id="canvas"
+        style="border:1px dashed #AAA"
+        tabindex=0>
+Your browser doesn't support canvas. At this point in the world that's actually
+pretty cool, well done!
+</canvas>
+<button onclick="resetGame()">(R)eset</button>
+<span style="font-size: 2rem; margin-left: 1rem;">Score:
+    <span style="font-weight: bold" id="score">0</span>
+</span>
+
+<script type="text/javascript">
+
+const palette = [
+    "#264653",
+    "#2A9D8F",
+    "#E9C46A",
+    "#F4A261",
+    "#E76F51",
+];
+
+const width = 800;
+const height = 600;
+
+function hypotenuse(w, h) {
+    return Math.sqrt(Math.pow(w, 2) + Math.pow(h, 2));
+}
+
+let canvas = document.getElementById("canvas");
+canvas.width = width;
+canvas.height = height;
+
+let score = document.getElementById("score");
+
+const whitelistedKeys = {
+    "ArrowUp": {},
+    "KeyW": {map: "ArrowUp"},
+    "ArrowLeft": {},
+    "KeyA": {map: "ArrowLeft"},
+    "ArrowRight": {},
+    "KeyD": {map: "ArrowRight"},
+    "ArrowDown": {},
+    "KeyS": {map: "ArrowDown"},
+    "Space": {},
+    "KeyR": {},
+};
+
+let keyboard = {};
+
+canvas.addEventListener('keydown', (event) => {
+    let keyInfo = whitelistedKeys[event.code];
+    if (!keyInfo) return;
+
+    let code = event.code;
+    if (keyInfo.map) code = keyInfo.map;
+
+    event.preventDefault();
+    keyboard[code] = true;
+});
+
+canvas.addEventListener('keyup', (event) => {
+    let keyInfo = whitelistedKeys[event.code];
+    if (!keyInfo) return;
+
+    let code = event.code;
+    if (keyInfo.map) code = keyInfo.map;
+
+    event.preventDefault();
+    delete keyboard[code];
+});
+
+let ctx = canvas.getContext("2d");
+
+let currTick;
+let drops;
+
+class Drop {
+    constructor(x, y, bounces, color) {
+        this.tick = currTick;
+        this.x = x;
+        this.y = y;
+        this.thickness = (bounces+1) * 0.25;
+        this.color = color ? color : palette[Math.floor(Math.random() * palette.length)];
+        this.winner = false;
+
+        this.maxRadius = hypotenuse(x, y);
+        this.maxRadius = Math.max(this.maxRadius, hypotenuse(width-x, y));
+        this.maxRadius = Math.max(this.maxRadius, hypotenuse(x, height-y));
+        this.maxRadius = Math.max(this.maxRadius, hypotenuse(width-x, height-y));
+
+        drops.push(this);
+
+        if (bounces > 0) {
+            new Drop(x, -y, bounces-1, this.color);
+            new Drop(-x, y, bounces-1, this.color);
+            new Drop((2*width)-x, y, bounces-1, this.color);
+            new Drop(x, (2*height)-y, bounces-1, this.color);
+        }
+    }
+
+    radius() { return currTick - this.tick; }
+
+    draw() {
+        ctx.beginPath();
+        ctx.arc(this.x, this.y, this.radius(), 0, Math.PI * 2, false);
+        ctx.closePath();
+        ctx.lineWidth = this.thickness;
+        ctx.strokeStyle = this.winner ? "#FF0000" : this.color;
+        ctx.stroke();
+    }
+
+    canGC() {
+        return this.radius() > this.maxRadius;
+    }
+}
+
+const playerRadius = 10;
+const playerMoveAccel = 0.5;
+const playerMoveDecel = 0.7;
+const playerMaxMoveSpeed = 4;
+const playerJumpSpeed = 0.08;
+const playerMaxHeight = 1;
+const playerGravity = 0.01;
+
+class Player{
+    constructor(x, y, color) {
+        this.x = x;
+        this.y = y;
+        this.z = 0;
+        this.xVelocity = 0;
+        this.yVelocity = 0;
+        this.zVelocity = 0;
+        this.color = color;
+        this.falling = false;
+        this.lastJumpHeight = 0;
+        this.loser = false;
+    }
+
+    act() {
+        if (keyboard["ArrowUp"]) {
+            this.yVelocity = Math.max(-playerMaxMoveSpeed, this.yVelocity - playerMoveAccel);
+        } else if (keyboard["ArrowDown"]) {
+            this.yVelocity = Math.min(playerMaxMoveSpeed, this.yVelocity + playerMoveAccel);
+        } else if (this.yVelocity > 0) {
+            this.yVelocity = Math.max(0, this.yVelocity - playerMoveDecel);
+        } else if (this.yVelocity < 0) {
+            this.yVelocity = Math.min(0, this.yVelocity + playerMoveDecel);
+        }
+
+        this.y += this.yVelocity;
+        this.y = Math.max(0+playerRadius, this.y);
+        this.y = Math.min(height-playerRadius, this.y);
+
+        if (keyboard["ArrowLeft"]) {
+            this.xVelocity = Math.max(-playerMaxMoveSpeed, this.xVelocity - playerMoveAccel);
+        } else if (keyboard["ArrowRight"]) {
+            this.xVelocity = Math.min(playerMaxMoveSpeed, this.xVelocity + playerMoveAccel);
+        } else if (this.xVelocity > 0) {
+            this.xVelocity = Math.max(0, this.xVelocity - playerMoveDecel);
+        } else if (this.xVelocity < 0) {
+            this.xVelocity = Math.min(0, this.xVelocity + playerMoveDecel);
+        }
+
+        this.x += this.xVelocity;
+        this.x = Math.max(0+playerRadius, this.x);
+        this.x = Math.min(width-playerRadius, this.x);
+
+        let jumpHeld = keyboard["Space"];
+
+        if (jumpHeld && !this.falling && this.z < playerMaxHeight) {
+            this.lastJumpHeight = 0;
+            this.zVelocity = playerJumpSpeed;
+        } else {
+            this.zVelocity = Math.max(-playerJumpSpeed, this.zVelocity - playerGravity);
+            this.falling = this.z > 0;
+        }
+
+        let prevZ = this.z;
+        this.z = Math.max(0, this.z + this.zVelocity);
+        this.lastJumpHeight = Math.max(this.z, this.lastJumpHeight);
+    }
+
+    draw() {
+        let y = this.y - (this.z * 40);
+        let radius = playerRadius * (this.z+1)
+
+        // draw main
+        ctx.beginPath();
+        ctx.arc(this.x, y, radius, 0, Math.PI * 2, false);
+        ctx.closePath();
+        ctx.lineWidth = 0;
+        ctx.fillStyle = this.color;
+        ctx.fill();
+        if (this.loser) {
+            ctx.strokeStyle = '#FF0000';
+            ctx.lineWidth = 2;
+            ctx.stroke();
+        }
+
+        // draw shadow, if in the air
+        if (this.z > 0) {
+            let radius = Math.max(0, playerRadius * (1.2 - this.z));
+            ctx.beginPath();
+            ctx.arc(this.x, this.y, radius, 0, Math.PI * 2, false);
+            ctx.closePath();
+            ctx.lineWidth = 0;
+            ctx.fillStyle = this.color+"33";
+            ctx.fill();
+        }
+    }
+}
+
+let player;
+let gameState;
+let numJumps;
+
+function resetGame() {
+    currTick = 0;
+    drops = [];
+    player = new Player(width/2, height/2, palette[0]);
+    gameState = 'play';
+    numJumps = 0;
+    canvas.focus();
+}
+resetGame();
+
+let requestAnimationFrame =
+    window.requestAnimationFrame ||
+    window.mozRequestAnimationFrame ||
+    window.webkitRequestAnimationFrame ||
+    window.msRequestAnimationFrame;
+
+function doTick() {
+    if (keyboard['KeyR']) {
+        resetGame();
+    }
+
+    if (gameState == 'play') {
+        let playerPrevZ = player.z;
+        player.act();
+        if (playerPrevZ > 0 && player.z == 0) {
+            let bounces = Math.floor((player.lastJumpHeight*1.8)+1);
+            console.log("spawning drop with bounces:", bounces);
+            new Drop(player.x, player.y, bounces);
+        } else if (playerPrevZ == 0 && player.z > 0) {
+            numJumps++;
+        }
+        score.innerHTML = numJumps;
+
+        if (player.z == 0) {
+            for (let i in drops) {
+                let drop = drops[i];
+                let dropRadius = drop.radius();
+                if (dropRadius < playerRadius * 1.5) continue;
+                let hs = Math.pow(drop.x-player.x, 2) + Math.pow(drop.y-player.y, 2);
+                if (hs > Math.pow(playerRadius + dropRadius, 2)) {
+                    continue;
+                } else if (Math.sqrt(hs) <= Math.abs(dropRadius-playerRadius)) {
+                    continue;
+                } else {
+                    console.log("game over");
+                    drop.winner = true;
+                    player.loser = true;
+                    gameState = 'gameOver';
+                }
+            }
+        }
+    }
+
+    ctx.clearRect(0, 0, canvas.width, canvas.height);
+    player.draw()
+    drops.forEach(drop => drop.draw());
+    drops = drops.filter(drop => !drop.canGC());
+
+    if (gameState == 'play') currTick++;
+    requestAnimationFrame(doTick);
+}
+requestAnimationFrame(doTick);
+
+</script>
+
+_Do you have the patience to wait<br/>
+till your mud settles and the water is clear?_
+
+## Backstory
+
+This is a game I originally implemented in lua, which you can find [here][orig].
+It's a fun concept that I wanted to show off again, as well as to see if I could
+whip it up in an evening in javascript (I can!)
+
+Send me your high scores! I top out around 17.
+
+[orig]: https://github.com/mediocregopher/ripple