From e20d5eef29b696f8c08b68a7dc1c455770265be0 Mon Sep 17 00:00:00 2001 From: Erik Onarheim Date: Wed, 17 Jan 2024 09:06:23 -0600 Subject: [PATCH] docs: fix first game sample docs --- site/docs/00-your-first-game.mdx | 233 +++++++++++++++++++++++- site/docs/02-fundamentals/03-actors.mdx | 2 +- 2 files changed, 225 insertions(+), 10 deletions(-) diff --git a/site/docs/00-your-first-game.mdx b/site/docs/00-your-first-game.mdx index a654f77ab..7c7f4fd7c 100644 --- a/site/docs/00-your-first-game.mdx +++ b/site/docs/00-your-first-game.mdx @@ -3,6 +3,15 @@ slug: /getting-started tags: ["#Tutorial"] --- +```twoslash include ex +/// +const Engine = ex.Engine; +const Actor = ex.Actor; +const Color = ex.Color; +const CollisionType = ex.CollisionType; +const vec = ex.vec; +``` + # Hello Excalibur ## Introduction @@ -79,9 +88,22 @@ It is important to call `game.start()` once you are done configuring your game o import { Engine } from 'excalibur'; ``` -`embed:sample-breakout/src/main.ts{snippet: "create-engine"}` +```ts twoslash +// @include: ex +// ---cut--- +// Create an instance of the engine. +// I'm specifying that the game be 800 pixels wide by 600 pixels tall. +// If no dimensions are specified the game will fit to the screen. +const game = new Engine({ + width: 800, + height: 600, +}); +``` -```typescript +```ts twoslash +// @include: ex +declare const game: ex.Engine; +// ---cut--- // Start the engine to begin the game. game.start(); ``` @@ -102,7 +124,31 @@ Actors must be added to a scene to be drawn or updated! `game.add(actor)` will a Below we are going to create the paddle Actor for our Breakout game. Actors can be given many parameters such as position, width, and height. -`embed:sample-breakout/src/main.ts{snippet: "create-paddle"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +// ---cut--- +// Create an actor with x position of 150px, +// y position of 40px from the bottom of the screen, +// width of 200px, height and a height of 20px +const paddle = new Actor({ + x: 150, + y: game.drawHeight - 40, + width: 200, + height: 20, + // Let's give it some color with one of the predefined + // color constants + color: Color.Chartreuse, +}); + +// Make sure the paddle can participate in collisions, by default excalibur actors do not collide with each other +// CollisionType.Fixed is like an object with infinite mass, and cannot be moved, but does participate in collision. +paddle.body.collisionType = CollisionType.Fixed; + +// `game.add` is the same as calling +// `game.currentScene.add` +game.add(paddle); +``` Open up your favorite browser and you should see something like this: @@ -110,7 +156,16 @@ Open up your favorite browser and you should see something like this: That’s neat, but this game is way more fun if things move around. Let’s make the paddle follow the mouse around in the x direction. The paddle will be centered on the mouse cursor. -`embed:sample-breakout/src/main.ts{snippet: "mouse-move"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const paddle: ex.Actor; +// ---cut--- +// Add a mouse move listener +game.input.pointers.primary.on("move", (evt) => { + paddle.pos.x = evt.worldPos.x; +}); +``` :::note @@ -128,30 +183,190 @@ In this case we want to handle the resolution ourselves to emulate the the way B Read more about the different [CollisionTypes](/docs/physics/#collision-types) that Excalibur supports. -`embed:sample-breakout/src/main.ts{snippet: "create-ball"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const paddle: ex.Actor; +// ---cut--- +// Create a ball at pos (100, 300) to start +const ball = new Actor({ + x: 100, + y: 300, + // Use a circle collider with radius 10 + radius: 10, + // Set the color + color: Color.Red, +}); +// Start the serve after a second +const ballSpeed = vec(100, 100); +setTimeout(() => { + // Set the velocity in pixels per second + ball.vel = ballSpeed; +}, 1000); + +// Set the collision Type to passive +// This means "tell me when I collide with an emitted event, but don't let excalibur do anything automatically" +ball.body.collisionType = CollisionType.Passive; +// Other possible collision types: +// "ex.CollisionType.PreventCollision - this means do not participate in any collision notification at all" +// "ex.CollisionType.Active - this means participate and let excalibur resolve the positions/velocities of actors after collision" +// "ex.CollisionType.Fixed - this means participate, but this object is unmovable" + +// Add the ball to the current scene +game.add(ball); +``` The ball is now setup to move at 100 pixels per second down and right. Next we will make the ball bounce off the side of the screen. Let’s take advantage of the `postupdate` event. -`embed:sample-breakout/src/main.ts{snippet: "screen-collision"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const ball: ex.Actor; +declare const ballSpeed: ex.Vector; +// ---cut--- +// Wire up to the postupdate event +ball.on("postupdate", () => { + // If the ball collides with the left side + // of the screen reverse the x velocity + if (ball.pos.x < ball.width / 2) { + ball.vel.x = ballSpeed.x; + } + + // If the ball collides with the right side + // of the screen reverse the x velocity + if (ball.pos.x + ball.width / 2 > game.drawWidth) { + ball.vel.x = ballSpeed.x * -1; + } + + // If the ball collides with the top + // of the screen reverse the y velocity + if (ball.pos.y < ball.height / 2) { + ball.vel.y = ballSpeed.y; + } +}); +``` ## Creating the bricks with Actors Breakout needs some bricks to break. To do this we calculate our brick layout and add them to the current scene. -`embed:sample-breakout/src/main.ts{snippet: "create-bricks"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const ball: ex.Actor; +declare const ballSpeed: ex.Vector; +declare type Actor = any; +// ---cut--- +// Build Bricks + +// Padding between bricks +const padding = 20; // px +const xoffset = 65; // x-offset +const yoffset = 20; // y-offset +const columns = 5; +const rows = 3; + +const brickColor = [Color.Violet, Color.Orange, Color.Yellow]; + +// Individual brick width with padding factored in +const brickWidth = game.drawWidth / columns - padding - padding / columns; // px +const brickHeight = 30; // px +const bricks: Actor[] = []; +for (let j = 0; j < rows; j++) { + for (let i = 0; i < columns; i++) { + bricks.push( + new Actor({ + x: xoffset + i * (brickWidth + padding) + padding, + y: yoffset + j * (brickHeight + padding) + padding, + width: brickWidth, + height: brickHeight, + color: brickColor[j % brickColor.length], + }) + ); + } +} + +bricks.forEach(function (brick) { + // Make sure that bricks can participate in collisions + brick.body.collisionType = CollisionType.Active; + + // Add the brick to the current scene to be drawn + game.add(brick); +}); +``` When the ball collides with bricks, we want to remove them from the scene. We use the `collisionstart` handler to accomplish this. This handler fires when objects first touch, if you want to know every time resolution is completed use `postcollision`. -`embed:sample-breakout/src/main.ts{snippet: "ball-brick-collision"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const ball: ex.Actor; +declare const ballSpeed: ex.Vector; +declare type Actor = any; +declare const bricks: ex.Actor[]; +// ---cut--- +// On collision remove the brick, bounce the ball +let colliding = false; +ball.on("collisionstart", function (ev) { + if (bricks.indexOf(ev.other) > -1) { + // kill removes an actor from the current scene + // therefore it will no longer be drawn or updated + ev.other.kill(); + } + + // reverse course after any collision + // intersections are the direction body A has to move to not be clipping body B + // `ev.content.mtv` "minimum translation vector" is a vector `normalize()` will make the length of it 1 + // `negate()` flips the direction of the vector + var intersection = ev.contact.mtv.normalize(); + + // Only reverse direction when the collision starts + // Object could be colliding for multiple frames + if (!colliding) { + colliding = true; + // The largest component of intersection is our axis to flip + if (Math.abs(intersection.x) > Math.abs(intersection.y)) { + ball.vel.x *= -1; + } else { + ball.vel.y *= -1; + } + } +}); + +ball.on("collisionend", () => { + // ball has separated from whatever object it was colliding with + colliding = false; +}); + +``` Finally, if the ball leaves the screen by getting past the paddle, the player loses! -`embed:sample-breakout/src/main.ts{snippet: "lose-condition"}` +```ts twoslash +// @include: ex +declare const game: ex.Engine; +declare const ball: ex.Actor; +declare const ballSpeed: ex.Vector; +declare type Actor = any; +declare const bricks: ex.Actor[]; +// ---cut--- +// Loss condition +ball.on("exitviewport", () => { + alert("You lose!"); +}); +``` ![Final Breakout screenshot](00-welcome/breakout-final.png) Congratulations! You have just created your first game in Excalibur! You can download this example [here](https://github.com/excaliburjs/sample-breakout). +Some things you could do on your own to take this sample further +* Add [[Sprite|sprite]] [[Graphic|graphics]] to the paddle, ball, and bricks +* Add a fun background instead of the blue +* Interpolate the paddle position between move events for a smoother look +* Make the ball ricochet differently depending where the paddle hits it + + It's time to [get introduced](/docs/engine) to the Engine for more examples. Once you're ready, you can browse the [API Reference](/docs/api/edge).