MatrixState的用法

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import android.opengl.Matrix;

//存储系统矩阵状态的类
public class MatrixState 
{  
	private static float[] mProjMatrix = new float[16];//4x4矩阵 投影用
    private static float[] mVMatrix = new float[16];//摄像机位置朝向9参数矩阵   
    private static float[] currMatrix;//当前变换矩阵
    public static float[] lightLocation=new float[]{0,0,0};//定位光光源位置
    public static FloatBuffer cameraFB;    
    public static FloatBuffer lightPositionFB;
      
    //保护变换矩阵的栈
    static float[][] mStack=new float[10][16];
    static int stackTop=-1;
    
    public static void setInitStack()//获取不变换初始矩阵
    {
    	currMatrix=new float[16];
    	Matrix.setRotateM(currMatrix, 0, 0, 1, 0, 0);
    }
    
    public static void pushMatrix()//保护变换矩阵
    {
    	stackTop++;
    	for(int i=0;i<16;i++)
    	{
    		mStack[stackTop][i]=currMatrix[i];
    	}
    }
    
    public static void popMatrix()//恢复变换矩阵
    {
    	for(int i=0;i<16;i++)
    	{
    		currMatrix[i]=mStack[stackTop][i];
    	}
    	stackTop--;
    }
    
    public static void translate(float x,float y,float z)//设置沿xyz轴移动
    {
    	Matrix.translateM(currMatrix, 0, x, y, z);
    }
    
    public static void rotate(float angle,float x,float y,float z)//设置绕xyz轴移动
    {
    	Matrix.rotateM(currMatrix,0,angle,x,y,z);
    }
    
    public static void scale(float x,float y,float z)
    {
    	Matrix.scaleM(currMatrix,0, x, y, z);
    }
    
    //插入自带矩阵
    public static void matrix(float[] self)
    {
    	float[] result=new float[16];
    	Matrix.multiplyMM(result,0,currMatrix,0,self,0);
    	currMatrix=result;
    }
    
    
    //设置摄像机
    static ByteBuffer llbb= ByteBuffer.allocateDirect(3*4);
    static float[] cameraLocation=new float[3];//摄像机位置
    public static void setCamera
    (
    		float cx,	//摄像机位置x
    		float cy,   //摄像机位置y
    		float cz,   //摄像机位置z
    		float tx,   //摄像机目标点x
    		float ty,   //摄像机目标点y
    		float tz,   //摄像机目标点z
    		float upx,  //摄像机UP向量X分量
    		float upy,  //摄像机UP向量Y分量
    		float upz   //摄像机UP向量Z分量		
    )
    {
        	Matrix.setLookAtM
            (
            		mVMatrix, 
            		0, 
            		cx,
            		cy,
            		cz,
            		tx,
            		ty,
            		tz,
            		upx,
            		upy,
            		upz
            );
        	
        	cameraLocation[0]=cx;
        	cameraLocation[1]=cy;
        	cameraLocation[2]=cz;
        	
        	llbb.clear();
            llbb.order(ByteOrder.nativeOrder());//设置字节顺序
            cameraFB=llbb.asFloatBuffer();
            cameraFB.put(cameraLocation);
            cameraFB.position(0);  
    }
    
    //设置透视投影参数
    public static void setProjectFrustum
    ( 
    	float left,		//near面的left
    	float right,    //near面的right
    	float bottom,   //near面的bottom
    	float top,      //near面的top
    	float near,		//near面距离
    	float far       //far面距离
    )
    {
    	Matrix.frustumM(mProjMatrix, 0, left, right, bottom, top, near, far);
    }
    
    //设置正交投影参数
    public static void setProjectOrtho
    (
    	float left,		//near面的left
    	float right,    //near面的right
    	float bottom,   //near面的bottom
    	float top,      //near面的top
    	float near,		//near面距离
    	float far       //far面距离
    )
    {    	
    	Matrix.orthoM(mProjMatrix, 0, left, right, bottom, top, near, far);
    }   
    //获取具体物体的总变换矩阵
    static float[] mMVPMatrix=new float[16];
    public static float[] getFinalMatrix()
    {	
    	Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, currMatrix, 0);
        Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);        
        return mMVPMatrix;
    }
    
    //获取具体物体的变换矩阵
    public static float[] getMMatrix()
    {       
        return currMatrix;
    }
    
    //获取投影矩阵
    public static float[] getProjMatrix()
    {
		return mProjMatrix;
    }
    
    //获取摄像机朝向的矩阵
    public static float[] getCaMatrix()
    {
		return mVMatrix;
    }
    
    
    
    //设置灯光位置的方法
    static ByteBuffer llbbL = ByteBuffer.allocateDirect(3*4);
    public static void setLightLocation(float x,float y,float z)
    {
    	llbbL.clear();
    	
    	lightLocation[0]=x;
    	lightLocation[1]=y;
    	lightLocation[2]=z;
    	
        llbbL.order(ByteOrder.nativeOrder());//设置字节顺序
        lightPositionFB=llbbL.asFloatBuffer();
        lightPositionFB.put(lightLocation);
        lightPositionFB.position(0);
    }
}