min3d Sample Project Study Notes

1. According to the content of "AndroidMainfest.xml", the startup activity is "SplashActivity".

2. The relationships between list items and the activities are:

"Hello, Jupiter" ---> ExampleRotatingPlanets
"Minimal example" ---> ExampleMostMinimal
"Vertex colors" ---> ExampleVertexColors
"Texture" ---> ExampleTextures
"Usage of Vertices class" ---> ExampleVerticesVariations
"Triangles, lines, points" ---> ExampleRenderType
"Camera, frustum (trackball)" ---> ExampleCamera
"Multiple lights" ---> ExampleMultipleLights
"Animating vertices" ---> ExampleAnimatingVertices
"Rendering subset of faces" ---> ExampleSubsetOfFaces
"Assigning textures dynamically" ---> ExampleAssigningTexturesDynamically
"MIP Mapping (on vs. off)" ---> ExampleMipMap
"Texture wrapping" ---> ExampleTextureWrap
"Multiple textures" ---> ExampleMultiTexture
"Texture offset" ---> ExampleTextureOffset
"3D inside layout" --> ExampleInsideLayout
"Load model from .obj file" ---> ExampleLoadObjFile
"Load multiple models from .obj file" ---> ExampleObjFileMultiple
"Load model from .3ds file" ---> ExampleLoad3DSFile
"Load animated .md2 file" ---> ExampleLoadMD2File
"Keyframe animation" ---> ExampleKeyframeAnimation

3. To create a min3d based activity, we have to create a activity class that is derived from RendererActivity class:
public class xxxxx extends RendererActivity.
Then we have to override initScene() and updateScene() functions.

4.1 Library source codes note:

4.1 Functions initScene() and updateScene() are declared in ISceneController interface class (interfaces/ISceneController.java)

4.2 When class RendererActivity (core/RendererActivity.java) is created, it will:
- Save current context to the STATIC class Shared (Shared.java)
- Create a scene object (core/Scene.java) (See 4.3 for more information)
- Create a renderer object (core/Renderer.java) for Android OpenGL surface and save the renderer to the STATIC class Shared.
- Assign the renderer object to the OpenGL surface
- Set render mode to RENDERMODE_CONTINUOUSLY.

4.3 When scene object is created, it will:
- Save the ISceneController Interface class so that it can call the overrided initScene() and updateScene() functions.
- Create a ManagedLightList object (core/ManagedLightList.java) for OpenGL light objects

4.4 The renderer object controls the FINAL output for a OpenGL surface. (More information can be found from Android development documents and other Android OpenGL tutorials) It is a good point to study how min3d displays 3D objects on the screen.
A renderer object has three important functions:
- onSurfaceCreated
- onSurfaceChanged
- onDrawFrame
And onDrawFrame() will be called frequently to update the scrren. (I.e. It is the critical part for performance...)

4.5 When the renderer object is created, it will:
- Save the created scene object to the variable _scene for later use
- Create two scratch buffers (one for Int and another for float (not used yet))
- Create TextureManager (core/TextureManager.java) and save it to the STATIC class Shared (textureManager will delete all existing textures in its list. See reset() of TextureManager class)
- Create other objects for doFps() function. (For statistic)

4.6 When OpenGL surface is created (onSurfaceCreated() is called), it will:
- Make use of a STATIC RenderCaps class (core/RenderCaps.java) to get the OpenGL capability
- save the current GL10 object for internal function use
- Do some initialization (reset())
- Initialize scene object (See 4.7 for more information)

4.7 When init() of scene object is called, it will:
- It will clear all attached Object3d objects (core/Object3d.java)
- Create a CameraVo Object (vos/CameraVo,java)
- Create a background color (vos/Color4Managed.java)
- Enable lighting flag
- Call the override initScene() function (which is defined in your Activity class)

4.8 When a Color4Managed object works as a Color4 object:
- Initialize internal r,g,b,a and float buffer.
- When any r,g,b,a is changed, dirty flag is set
- IDirtyParent parent is not used so onDirty() of scene object is no use

4.9 CameraVo object just setup some Numer3d objects (vos/Number3d.java) and a FrustumManaged object (vos/FrustumManaged.java) for public access.

4.10 Therefore, when the override initScene() function is called,
- You can access the STATIC Shared class to get:
- the scene object to add Object3d objects and/or light objects (vos/Light.java) (see 4.2 and 4.3)
- the TextureManager object (see 4.5) to add textures
- You can access the RenderCaps object (see 4.6) to get OpenGL capability
- Also, some default settings are set (see 4.2, 4.5 and 4.7)