Cross platform, mobile games development

Game engines

HTML5 game engines

Use HTML5 <canvas> element

and/or webGL if available

closed-source

See all on html5gameengine.com

Custom canvas runtimes

WebView

HTML5 on mobile

Cordova,

Cordova + Crosswalk on Android,

Cordova + WKWebView on iOS 

iOS only

closed-source

Hybrid game engines

Lua / C++

Render with OpenGL ES/native platform libraries, run all the game logic with a cross-platform language  

GDSCript/C++

JS / C++

Lua

"Native" game engines

C#

C++

C++

Game [engine] 

architecture

Scene graph

Scene

Layer/View

Layer/View

DisplayObject

Text

Sprite

Particles

Sprite

SceneStack/Director

Rendered objects are stored in a graph

Lower levels rendering engines (SDL, OpenGL, WebGL, Canvas) don't have graphs, only primitives

Game loop

Manage inputs

Update world

Update physics

Render

Update time

dt = time elapsed since last frame

fps = 1 / dt

{

check collisions, move objects, update scores (business logic)...

{

Audio

HTML5 games

HTML5 audio, WebAudio API

Hybrid/Native games

Most engines have a

built-in audio support

Physics

You need to map your entities to the physics engine bodies 

World

Joint

RigidBody

Fixture

RigidBody

Fixture

Fixture

Forces can be applied on body

Callbacks can be attached for collisions

Collisions

  • Either use a physics engine
  • Roll your own logic:
  • Bounding boxes (very simple collision detection)
  • Hitboxes made with polygons (use an algorithm like SAT)
  • If necessary, divide the space
    to avoid collision checks
    (spatial hashing, quadtree)

Games technical considerations

Performance

Discard objects, use simple physics models, split heavy computations if possible in more than one frame.

Rendering

Logic

Avoid rendering objects far from the player (culling) 

In general, minimize objects and textures

Avoid creating too much objects, release unused ones/too far from player 

Memory usage

Memory allocation

Garbage collector can be a frame killer

Avoid creating objects, reuse an existing one or a pool of objects

About Javascript

iOS JS engine and devices are quite fast

Raw performance

Harder to get a jank free game on Android even with Crosswalk

Mobile cross-platform games creation

By Florian Rival

Mobile cross-platform games creation

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