android opengl纹理贴图无法成功，请指教

大家好。

 

今天在学习opengl的，到了纹理贴图这里，按照“生成纹理 -> 绑定纹理 -> 画图”的步骤进行，发现几何图形可以画出来，但是纹理却死活没有出来。尝试了各种设置，都不行，不知道哪里出了问题。现在我把代码贴出来，希望有经验的朋友能给我一点指点。希望大家不吝赐教。

 

 

package com.gl;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

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

import test.opengl.R;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.opengl.GLUtils;
import android.opengl.GLSurfaceView.Renderer;


public class OpenGlRender implements Renderer {  
    private float z = -1;
    private float[] vertices = {
    		0, 0, z,
    		1, 0, z,
    		1, 1, z,
    		0, 1, z,
    		-1, 1, z,
    		-1, 0, z,
    		-1, -1, z,
    		0, -1, z,
    		1, -1, z
    };
    
    private float[] colors = {
    	1, 0, 0, 1, //r, g, b, a
    	0, 1, 0, 1,
    	0, 0, 1, 1,
    	1, 1, 0, 1
    };
    
    private float[] texCoor = {
    	0f, 0f,
    	1f, 0f,
    	0f, 1f,
    	1f, 1f
    };
    private FloatBuffer _clrBuffer;
    private ShortBuffer _indexBuffer;   
    private FloatBuffer _vertexBuffer;   
    private FloatBuffer _texBuffer;
    private int _nrOfVertices = 4;
    
    private int[] mTexIds = new int[2];
    private Bitmap mBm;

    private Context mCtx;

    OpenGlRender(Context ctx){
    	mCtx = ctx;
    }
    
    
    
    @Override  
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {   
        // TODO Auto-generated method stub   
           
    	gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);   
    	gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
    	gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    	gl.glEnable(GL10.GL_TEXTURE_2D);
    	
    	mBm = BitmapFactory.decodeResource(mCtx.getResources(), R.drawable.fig01_d);
    	updateBitmap(mBm);
    	gl.glGenTextures(1, mTexIds, 0);

    	gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexIds[0]);
    	gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
    	gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
    	gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
    	gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);
    	GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, mBm, 0);
    	
    	
    	
    	mBm.recycle();
    	
        initTriangle();   
    }   
    
    
    private void updateBitmap(Bitmap src){
    	if(src == null)
    		return;
    	
    	int w = pow2(src.getWidth());
    	int h = pow2(src.getHeight());
    	Bitmap b = Bitmap.createBitmap(w, h, 
    			src.hasAlpha() ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
    	Canvas c = new Canvas(b);
    	c.drawBitmap(src, 0, 0, null);
    	src = b;
    }
    
    
    private int pow2(float val){
    	int x = (int) (Math.log(val) / Math.log(2));
    	
    	if((1 << x) >= val)
    		return 1 << x;
    	else
    		return 1 << (1 + x);
    }
    
    
    @Override  
    public void onSurfaceChanged(GL10 gl, int width, int height) {   
        gl.glViewport(0, 0, width, height);   
    }   
    
    private float angle = 0;
    
    @Override  
    public void onDrawFrame(GL10 gl) {  
    	gl.glClear(GL10.GL_COLOR_BUFFER_BIT);   
    	gl.glClearColor(0, 0, 1.0f, 1.0f);   
        gl.glColor4f(1f, 0f, 0f, 1f);   
         
        gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, _texBuffer);
        
        //size: number of coordinates per vertex;
	    //stride: offset between 2 consecutive vertices;
	    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, _vertexBuffer);
	    //gl.glColorPointer(4, GL10.GL_FLOAT, 0, _clrBuffer);
	    //gl.glDrawElements(GL10.GL_TRIANGLE_FAN, _nrOfVertices, GL10.GL_UNSIGNED_SHORT, _indexBuffer);   
	    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, _nrOfVertices);
	    

	    angle++;
    }   
    
    
    private void initTriangle() {   
        // float has 4 bytes   
        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);   
        vbb.order(ByteOrder.nativeOrder());   
        _vertexBuffer = vbb.asFloatBuffer();
        _vertexBuffer.put(vertices);
        _vertexBuffer.position(0);
           
        // short has 4 bytes   
        ByteBuffer ibb = ByteBuffer.allocateDirect(_nrOfVertices * 2);   
        ibb.order(ByteOrder.nativeOrder());   
        _indexBuffer = ibb.asShortBuffer();   
        for(short i = 0; i < _nrOfVertices; i++){
        	_indexBuffer.put(i, i);
        }
        _indexBuffer.position(0);   
        
        
        ByteBuffer clr= ByteBuffer.allocateDirect(colors.length * 4);
        clr.order(ByteOrder.nativeOrder());
        _clrBuffer = clr.asFloatBuffer();
        _clrBuffer.put(colors);
        _clrBuffer.position(0);
        
        
        ByteBuffer tex = ByteBuffer.allocate(texCoor.length * 4);
        tex.order(ByteOrder.nativeOrder());
        _texBuffer = tex.asFloatBuffer();
        _texBuffer.put(texCoor);
        _texBuffer.position(0);
    }   

} 

 

 

 

评论

3 楼 coohcooh 2011-12-09  

楼上是用哪个SDK开发这个的？2.2吗？我用2.2但是无法运行楼主的代码呢，刚学android，请指教下，谢谢啦

2 楼 freedomray 2011-10-18  

进一步发现，其实并非不可使用FloatBuffer作为纹理坐标，只是在分配内存时有点隐蔽的错误：

ByteBuffer tex = ByteBuffer.allocate(texCoor.length * 4);  

这个地方，其实应该使用：

ByteBuffer tex = ByteBuffer.allocateDirect(texCoor.length * 4);  

1 楼 freedomray 2011-10-18  

发现了错误所在。

原来纹理数组需要用整数，而不能用float。
应该定义为：

int one = 0x10000;
private IntBuffer texIntCoor = IntBuffer.wrap(new int[]{
    		//0, 0, one, 0, 0, one, one, one,
    		0, one, one, one, 0, 0, one, 0, 
    });

在应用纹理的时候，需要使用GL_FIXED类型：

gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, texIntCoor);