Transcript Intro to JME

Intro to Java Monkey Engine
Download JME SDK @
http://hub.jmonkeyengine.org/down
loads/
JME Technology
• JME stands for the java monkey engine: a game engine written in
java and built upon LWJGL (light-weight java GL -- a java binding for
OpenGL)
– OpenGL is a platform independent library for 2D and 3D graphics.
– For our purposes, OpenGL is far too low-level for the kinds of
graphics programming we'd like to accomplish
• OpenGL concerns itself with fast, often hardware accelerated,
rendering of basic geometric primitives)
– We appeal to a game engine to provide additional high-level
functionality
• Note: JME provides audio capability via OpenAL support. JME
supports Ogg Vorbis (.ogg) and uncompressed PCM Wave (.wav)
formats.
– We can use Audicity (http://audacity.sourceforge.net/) to convert
other formats to these
Game-Level Objects
• Main Application (SimpleApplication) - A base class from which the
custom game inherits
– Provides method hooks (i.e., callbacks) to initialize a game
(simpleInitApp) update game (simpleUpdate) objects and re-display
(simpleRender) objects.
– InputManager - A class to manage all device input (e.g., keyboard,
mouse, joystick) and present that input to the application for
handling.
– Display - A class to insulate the game from the device specific
characteristics of platform on which the game is being run. The
Display also encapsulates the features of window management.
– Renderer - An abstraction of the OpenGL state and rendering
pipeline as discussed in class. OpenGL is a state-driven system.
That is, you define a graphics state as a set of rendering attributes
and then send a sequence of geometric data to the renderer which
then is drawn subject to the current attributes.
– The three classes above are referred collectively as the JME context.
The Main Game Loop
Game-Level Objects (cont)
• Main Application (SimpleApplication) - A base class from which the
custom game inherits
– Scene Graph - A class to manage the objects in the scene
– Camera - A class to encapsulate the eye position and its attributes
(e.g., field of view, depth of field, up vector, etc.).
– Math Library for 3D Graphics (functions to handle vectors,
matrices, geometric data, collisions, etc.).
– Model Importers - A fully featured game engine provides for
importing mesh models from any of several different modeling
programs.
The Scene Graph
• A grouping of Nodes in a tree hierarchy according
(most of the time) to spatial location.
• Spatially because …
–
–
–
–
Game objects are typically located by location
Allows for fast culling
Tree structure natural for many game objects
Easy to express, create tools for this data structure
• Spatial is an abstract class allowing uniform treatment
of:
– Node (internal, invisible, grouping class, transformable)
– Geometry (leaf, visible—mesh and material—
transformable).
Beginning a Project
In the jMonkeyEngine SDK:
• Choose File→New Project… from the main menu.
• In the New Project wizard, select the template
JME3→Basic Game. Click Next.
– Specify a project name, e.g. "HelloWorldTutorial"
– Specify a path where to store your new project, e.g. a
jMonkeyProjects directory in your home directory.
•
Click Finish.
Understanding the JME App Structure
public class Main extends SimpleApplication {
public static void main(String[] args) {
Main app = new Main();
app.start();
}
Understanding the JME App Structure
public class Main extends SimpleApplication {
.
@Override
public void simpleInitApp() {
Box b = new Box(Vector3f.ZERO, 1, 1, 1);
Geometry geom = new Geometry("Box", b);
Material mat = new Material(assetManager, “…");
mat.setColor("Color", ColorRGBA.Blue);
geom.setMaterial(mat);
rootNode.attachChild(geom);
Understanding the JME App Structure
public class Main extends SimpleApplication {
@Override
public void simpleUpdate(float tpf) {
//TODO: add update code
}
@Override
public void simpleRender(RenderManager rm) {
//TODO: add render code
}
}
Typical Game Objects
• Spatial: Spatials are abstract and exist to
allow handling of the Nodes and Geometry
uniformly.
– Node (internal, i.e. has children) contains
transformations and links to children (no
Mesh or Material--invisible)
– Geometry (leaf) contains transformations
and visible characteristics, i.e., Mesh and
Material
Typical Game Objects
– Geometry (leaf) contains transformations
and visible characteristics, i.e., Mesh and
Material
• Mesh
• Material
–Color (Ambient, Diffuse, Emmisive, Specular)
- Base color of an object that is not
influenced by a color map
–Texture
»Color Map
»Specular Map
»Bump Map (Height Map, Normal Map)
Typical Game Objects
• Distinguished Spatials
– rootNode
– Camera
Getting Started
One of the better ways to learn what you can do
in JME is to:
• Examine the JME Tests
• Complete the JME "Tutorial Series
(http://hub.jmonkeyengine.org/wiki/doku.ph
p/jme3:beginner)