andriod 3d 初探

[/color]看了sdk中的3d的例子,自已写了一个棱形的例子.

[b[color=red]]Prism.java[/b]

package cn.ynw520;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;

import javax.microedition.khronos.opengles.GL10;

/**
 * A vertex shaded prism.
 */
class Prism
{
    public Prism()
    {
        int one = 0x10000;
        
        //这里是四个顶点(按顺时针方向来存储)
        int vertices[] = {
                0, 0, one*2,
                0, one, 0,
                -one, -one,0,
                one, -one,0,
        };

        //每个顶点的颜色
        int colors[] = {
                0,    0,    0,  one,
                one,    0,    0,  one,
                one,  one,    0,  one,
                0,  one,    0,  one,
        };

		//按顺时针,由点组成的4个面,一行代表一个面
        byte indices[] = {
                0, 1, 2,
                0, 2, 3,
                0, 3, 1,
                1, 2, 3,
        };

        
        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
        vbb.order(ByteOrder.nativeOrder());
        mVertexBuffer = vbb.asIntBuffer();
        mVertexBuffer.put(vertices);
        mVertexBuffer.position(0);

        ByteBuffer cbb = ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        mColorBuffer = cbb.asIntBuffer();
        mColorBuffer.put(colors);
        mColorBuffer.position(0);

        mIndexBuffer = ByteBuffer.allocateDirect(indices.length);
        mIndexBuffer.put(indices);
        mIndexBuffer.position(0);
    }

    public void draw(GL10 gl)
    {
        gl.glFrontFace(gl.GL_CW);     //说明按顺时针方向
        gl.glVertexPointer(3, gl.GL_FIXED, 0, mVertexBuffer); //这个是画点,3代表维数,第二个参数代表值的类型,第三个好像都为0
        gl.glColorPointer(4, gl.GL_FIXED, 0, mColorBuffer);   //画点的颜色
        gl.glDrawElements(gl.GL_TRIANGLES, 12, gl.GL_UNSIGNED_BYTE, mIndexBuffer);  //开始画了,第一个代表用什么形状画(三角形),第二个参数代表组成面的点数,第三个是点数据的类型
    }

    private IntBuffer   mVertexBuffer;
    private IntBuffer   mColorBuffer;
    private ByteBuffer  mIndexBuffer;
}

PrismRender.java

package cn.ynw520;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLSurfaceView.Renderer;

public class PrismRender implements Renderer {
	
	 public PrismRender(boolean useTranslucentBackground) {
	        mTranslucentBackground = useTranslucentBackground;
	        mPrism = new Prism();
	    }

	public void onDrawFrame(GL10 gl) {
		gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);  //清除

        gl.glMatrixMode(GL10.GL_MODELVIEW);   //mode
        gl.glLoadIdentity();                  // 重置模型观察矩阵
        gl.glTranslatef(0, 0, -3.0f);         //相当于原点移动
        gl.glRotatef(mAngle, 0, 1, 0);        //绕y轴转动,mAngel代表角度
        gl.glRotatef(mAngle*0.25f,  1, 0, 0); //绕x轴转动

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); //说明数据可以画
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        mPrism.draw(gl);
        mAngle += 1.2f;
	}

	public void onSurfaceChanged(GL10 gl, int width, int height) {
		gl.glViewport(0, 0, width, height);

        float ratio = (float) width / height;
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
	}

	public void onSurfaceCreated(GL10 gl, EGLConfig config) {
		gl.glDisable(GL10.GL_DITHER);

        /*
         * Some one-time OpenGL initialization can be made here
         * probably based on features of this particular context
         */
         gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,
                 GL10.GL_FASTEST);

         if (mTranslucentBackground) {
             gl.glClearColor(0,0,0,0);
         } else {
             gl.glClearColor(1,1,1,1);
         }
         gl.glEnable(GL10.GL_CULL_FACE);
         gl.glShadeModel(GL10.GL_SMOOTH);
         gl.glEnable(GL10.GL_DEPTH_TEST);
	}
	
	private boolean mTranslucentBackground;
	private float mAngle;
	private Prism mPrism;
}

prismActivity.java

package cn.ynw520;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;

public class PrismActivity extends Activity {
	  @Override
	    protected void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);

	        mGLSurfaceView = new GLSurfaceView(this);
	        mGLSurfaceView.setRenderer(new PrismRender(false));
	        setContentView(mGLSurfaceView);
	    }

	    @Override
	    protected void onResume() {
	        super.onResume();
	        mGLSurfaceView.onResume();
	    }

	    @Override
	    protected void onPause() {
	        super.onPause();
	        mGLSurfaceView.onPause();
	    }

	    private GLSurfaceView mGLSurfaceView;
}