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@@ -1,6 +1,6 @@
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= The Scene Graph and Other jME3 Terminology
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-:author:
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-:revnumber:
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+:author:
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+:revnumber:
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:revdate: 2016/03/17 20:48
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:keywords: spatial, node, mesh, geometry, scenegraph, rootnode
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:relfileprefix: ../
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@@ -10,7 +10,7 @@ ifdef::env-github,env-browser[:outfilesuffix: .adoc]
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Before you start making games, make sure you understand general <<jme3/terminology#,3D Gaming terminology>>.
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-Second, if you are a beginner, we recommend our <<jme3/scenegraph_for_dummies#,Scene Graph for Dummies>> presentation for a visual introduction to the concept of a scene graph.
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+Second, if you are a beginner, we recommend our <<jme3/scenegraph_for_dummies#,Scene Graph for Dummies>> presentation for a visual introduction to the concept of a scene graph.
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Then continue learning about jME3 concepts here.
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@@ -28,7 +28,7 @@ The coordinate system consists of:
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* The _origin_, a single central point in space.
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** The origin point is always at coordinate zero, in Java: `new Vector3f(0,0,0)`.
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-* Three _coordinate axes_ that are mutually perpendicular, and meet in the origin.
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+* Three _coordinate axes_ that are mutually perpendicular, and meet in the origin.
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** The X axis starts left and goes right.
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** The Y axis starts below and goes up.
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** The Z axis starts away from you, and goes towards you.
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@@ -47,7 +47,7 @@ The unit of meassurement (“one step) in jME3 is the *world unit*, short: wu. T
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For your orientation:
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* The default camera's location is `Vector3f(0.0f, 0.0f, 10.0f)`.
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-* The default camera is looking in the direction described by the (so called) negative Z unit vector `Vector3f(0.0f, 0.0f, -1.0f)`.
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+* The default camera is looking in the direction described by the (so called) negative Z unit vector `Vector3f(0.0f, 0.0f, -1.0f)`.
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This means the player's point of view is on the positive side of the Z axis, looking back, towards the origin, down the Z axis.
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@@ -60,9 +60,9 @@ By default, jME3 uses the following common navigation inputs
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[cols="3", options="header"]
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|===
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-a| Game Inputs
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-a| Camera Motion
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-a| Player POV
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+a| Game Inputs
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+a| Camera Motion
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+a| Player POV
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a|Press the W and S keys
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a|move the camera forward, and backward
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@@ -91,13 +91,13 @@ These default settings are called “WASD keys and “Mouse Look. You can custom
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== Scene Graph and RootNode
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-The _scene graph_ represents your 3D world. Objects in the jME3 scene graph are called <<jme3/advanced/spatial#,Spatial>>s. Everything attached to the parent _rootNode_ is part of your scene. Your game inherits the `rootNode` object from the `SimpleApplication` class.
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+The _scene graph_ represents your 3D world. Objects in the jME3 scene graph are called <<jme3/advanced/spatial#,Spatial>>s. Everything attached to the parent _rootNode_ is part of your scene. Your game inherits the `rootNode` object from the `SimpleApplication` class.
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image::jme3/intermediate/scene-graph.png[scene-graph.png,width="",height="",align="center"]
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-* _Attaching_ a Spatial to the rootNode (or its child nodes) adds it to the scene;
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+* _Attaching_ a Spatial to the rootNode (or its child nodes) adds it to the scene;
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* _Detaching_ a Spatial from the rootNode (or its child nodes) removes it from the scene.
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All objects in the scene graph are in a parent-child relationship. When you transform (move, rotate, scale) one parent, all its children follow.
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@@ -105,42 +105,42 @@ All objects in the scene graph are in a parent-child relationship. When you tran
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[NOTE]
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====
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-The scene graph only manages the parent-child relationship of spatials. The actual location, rotation, or scale of an object is stored inside each Spatial.
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+The scene graph only manages the parent-child relationship of spatials. The actual location, rotation, or scale of an object is stored inside each Spatial.
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====
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== Spatials: Node vs Geometry
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-A Spatial can be transformed (in other words, it has a location, a rotation, and a scale). A Spatial can be loaded and saved as a .3jo file. There are two types of Spatials, _Nodes_ and _Geometries_:
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+A Spatial can be transformed (in other words, it has a location, a rotation, and a scale). A Spatial can be loaded and saved as a .3jo file. There are two types of Spatials, _Node_ and _Geometry_:
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[cols="10,45,45", options="header"]
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|===
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-<a|
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-2+a| Spatial
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+<a|
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+2+a| Spatial
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-a| Purpose:
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-2+a| A Spatial is an abstract data structure that stores transformations (translation, rotation, scale).
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+a| Purpose:
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+2+a| A Spatial is an abstract data structure that stores transformations (translation, rotation, scale).
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-<a|
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-a| Geometry
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-a| Node
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+<a|
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+a| Geometry
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+a| Node
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-a| Visibility:
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-a| A visible 3-D object.
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-a| An invisible “handle for a group of objects.
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+a| Visibility:
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+a| A visible 3-D object.
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+a| An invisible “handle for a group of objects.
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-a| Purpose:
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-a| A Geometry represents the “look of an object: Shape, color, texture, opacity/transparency.
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-a| A Node groups Geometries and other Nodes together: You transform a Node to affect all attached Nodes (parent-child relationship).
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+a| Purpose:
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+a| A Geometry represents the “look of an object: Shape, color, texture, opacity/transparency.
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+a| A Node groups Geometries and other Nodes together: You transform a Node to affect all attached Nodes (parent-child relationship).
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-a| Content:
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-a| Transformations, mesh, material.
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-a| Transformations. No mesh, no material.
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+a| Content:
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+a| Transformations, mesh, material.
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+a| Transformations. No mesh, no material.
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-a| Examples:
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-a| A box, a sphere, player, a building, a piece of terrain, a vehicle, missiles, NPCs, etc…
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-a| The rootNode, the guiNode, an audioNode, a custom grouping node for a vehicle plus its passengers, etc.
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+a| Examples:
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+a| A box, a sphere, player, a building, a piece of terrain, a vehicle, missiles, NPCs, etc…
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+a| The rootNode, the guiNode, an audioNode, a custom grouping node for a vehicle plus its passengers, etc.
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|===
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mitm001