pyramidcanvas.java

3D J2ME 代码集合

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;

import javax.microedition.m3g.*;

class pyramidCanvas extends GameCanvas implements Runnable{
  
    private Graphics3D g3d; // Graphics object used to render the world.
    private World world; // This world contains the camera and the pyramidMesh.
    private Camera camera; // the camera in the scene
    private Mesh pyramidMesh; // the pyramid in the scene
    
    public pyramidCanvas(){
        super(false);
        
        setFullScreenMode(true);
        
        g3d = Graphics3D.getInstance();
        world = new World();

        camera = new Camera();
        world.addChild(camera); // add the camera to the world.

        float w = getWidth();
        float h = getHeight();

        // Constructs a perspective projection matrix and sets that as the current projection matrix.
        camera.setPerspective(60.0f, w / h, 0.1f, 50f);
        
        pyramidMesh = createpyramid(); // create our pyramid.
        pyramidMesh.setTranslation(0.0f, 0.0f, -3.0f); // move the pyramid 3 units into the screen.
        world.addChild(pyramidMesh); // add the pyramid to the world

        world.setActiveCamera(camera);
        
        Thread t = new Thread(this);
        t.start();
    }

    public void draw3D(Graphics g){
        try{
            g3d.bindTarget(g); // Binds the given Graphics or mutable Image2D as the rendering target of this Graphics3D
            g3d.render(world); // Render the world
        }finally{
            g3d.releaseTarget();
        }
    }

    public void run() {
        Graphics g = getGraphics();

        while(true){
            // rotate the pyramid 1 degree around the Y-axis.
            pyramidMesh.postRotate(3.0f, 0.0f, 1.0f, 0.0f);

            draw3D(g);
            flushGraphics();
        }
    }


    // this method creates a colored pyramid.
    private Mesh createpyramid(){
        
        // The vertices used by the pyramid. x, y, z
        short []POINTS = new short[] {-1, -1, 1, // point 1
                                                            1, -1, 1, // point 2
                                                            1, -1, -1, // point 3
                                                            -1, -1, -1, // point 4
                                                            0, 1, 0}; // point 5, top
                                                            
                                                            
        // The points sequence.
        int []INDICES = new int[] {
        	0, 1, 4, 
        1, 2, 4, 
        2, 3, 4, 
        3, 0, 4, 
        2, 1, 0, 
        2, 0, 3};
        byte []COLORS = new byte[] {127, 0, 0, //R
                                                        0, 127, 0,  //G
                                                        0, 0, 127, //B
                                                        127, 0, 127, //B
                                                        0, 127, 127};//B
                                                        

        // The length of each sequence in the indices array.
        int []LENGTH = new int[] {3, 3, 3, 3, 3, 3}; // the pyramid is built by six triangles
        
        VertexArray POSITION_ARRAY, COLOR_ARRAY;
        IndexBuffer INDEX_BUFFER;
        
        // Create a VertexArray to be used by the VertexBuffer
        POSITION_ARRAY = new VertexArray(POINTS.length / 3, 3, 2);
        POSITION_ARRAY.set(0, POINTS.length / 3, POINTS);
        COLOR_ARRAY = new VertexArray(COLORS.length / 3, 3, 1);
        COLOR_ARRAY.set(0, COLORS.length / 3, COLORS);
        INDEX_BUFFER = new TriangleStripArray(INDICES, LENGTH);
        
        // VertexBuffer holds references to VertexArrays that contain the positions, colors, normals, 
        // and texture coordinates for a set of vertices
        VertexBuffer vertexBuffer = new VertexBuffer();
        vertexBuffer.setPositions(POSITION_ARRAY, 1.0f, null);
        vertexBuffer.setColors(COLOR_ARRAY);
        
        // Create the 3D object defined as a polygonal surface
        Mesh mesh = new Mesh(vertexBuffer, INDEX_BUFFER, null);
        
        Appearance appearance = new Appearance(); // A set of component objects that define the rendering attributes of a Mesh
        PolygonMode polygonMode = new PolygonMode(); // An Appearance component encapsulating polygon-level attributes
        polygonMode.setPerspectiveCorrectionEnable(true);
        polygonMode.setCulling(PolygonMode.CULL_BACK); // By using CULL_NONE all faces of the pyramid will be shown.
        polygonMode.setShading(PolygonMode.SHADE_SMOOTH); // use a smooth shading of the colors on the pyramid.
        appearance.setPolygonMode(polygonMode);
        
        mesh.setAppearance(0, appearance); // Set the appearance to the 3D object
        
        return mesh;
        
    }    

}