Android OpenGL10 多纹理效果 <5>

接着前面那一篇文章,上一篇没有特别介绍API,这里先介绍几个常见的API,然后给出验证程序:

glGenTextures(GLsizei n, GLuint *textures)

参数一:用来生成文理数量;

参数二:储存一个纹理索引,传入数组;

方法:根据纹理参数返回n个纹理索引;

void glBindTexture(	GLenum target,
 	GLuint texture);

参数一:  指定纹理要绑定到的目标,可配置参数很多:GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_TEXTURE_1D_ARRAY, GL_TEXTURE_2D_ARRAY, GL_TEXTURE_RECTANGLE, GL_TEXTURE_CUBE_MAP, GL_TEXTURE_CUBE_MAP_ARRAY, GL_TEXTURE_BUFFER, GL_TEXTURE_2D_MULTISAMPLE or GL_TEXTURE_2D_MULTISAMPLE_ARRAY中的一个.

一般选GL_TEXTURE_2D作为输入.

参数二 : 指定纹理的名称(即ID),即第一个方法返回的纹理索引数组中的一个.

void texImage2D (int target, int level, Bitmap bitmap, int border)

参数一 : 一般设置为GL_TEXTURE_2D;

参数二 : 一般为0;

参数三 : 需要的图像;

参数四 : 边框间距(默认可以设为0);

void glTexParameterx (int target, int pname, int param)

参数一 : 指定纹理绑定的目标,参考第二个方法参数一,一般选GL_TEXTURE_2D;

参数二 : 纹理过滤,可选GL_TEXTURE_MAG_FILTER(放大过滤)和GL_TEXTURE_MIN_FILTER(缩小过滤),当然还有GL_TEXTURE_WRAP_S,GL_TEXTURE_WRAP_T;

参数三 : 如果参数二设置为过大过小滤镜,这个参数一般选择:GL_NEAREST,GL_LINEAR,其中意义:

GL_LINEAR : 使用了线性滤波(采用最靠近象素中心的四个象素的加权平均值)的纹理贴图。这需要机器有相当高的处理能力，但GL_LINEAR提供了比较光滑的效果;

GL_NEAREST : 则采用坐标最靠近象素中心的像素，这有可能使图像走样。从原理上讲，这种方式没有真正进行滤波。它只占用很小的处理能力。唯一的好处是所需计算比GL_LINEAR要少，这样我们的工程在很快和很慢的机器上都可以正常运行;

如果第二个参数不是前面两种,一般这里选择GL_CLAMP,其中意义:

GL_CLAMP : 将纹理坐标限制在0.0,1.0的范围之内.如果超出了会如何呢.不会错误,只是会边缘拉伸填充;

利用上面的几个方法既可以配置所需要的纹理效果出来.

如果要绑定要图形面上,可以在执行绘图之前:执行绑定操作.

void glBindTexture(	GLenum target,
 	GLuint texture);

然后再执行glDrawArrays或glDrawElements方法.

然后下面看看如何使用上面的套路来制作一个多纹理效果.

工程仍然采用上一篇的工程,只是在写两个类.

package org.pumpkin.pumpkinbasictexture.multexture;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLUtils;

import org.pumpkin.pumpkinbasictexture.R;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/5/5.
 */
public class MulTextureCube {

    private int[] textures;
    private Bitmap[] mBitmap=new Bitmap[6];

    private FloatBuffer vertexBuffer;
    private FloatBuffer texBuffer;

    private float[] vertices={
            -1.0f, -1.0f, 0.0f,  // 0. left-bottom-front
            1.0f, -1.0f, 0.0f,  // 1. right-bottom-front
            -1.0f,  1.0f, 0.0f,  // 2. left-top-front
            1.0f,  1.0f, 0.0f   // 3. right-top-front
    };

    float[] texCoords={
            0.0f, 1.0f,  // A. left-bottom (NEW)
            1.0f, 1.0f,  // B. right-bottom (NEW)
            0.0f, 0.0f,  // C. left-top (NEW)
            1.0f, 0.0f   // D. right-top (NEW)
    };

    int[] textureIDs=new int[1];

    public MulTextureCube(Context context){

        mBitmap[0] = BitmapFactory.decodeResource(context.getResources(), R.drawable.gh);
        mBitmap[1] = BitmapFactory.decodeResource(context.getResources(), R.drawable.ghh);
        mBitmap[2] = BitmapFactory.decodeResource(context.getResources(), R.drawable.gtr);
        mBitmap[3] = BitmapFactory.decodeResource(context.getResources(), R.drawable.ghr);
        mBitmap[4] = BitmapFactory.decodeResource(context.getResources(), R.drawable.yel);
        mBitmap[5] = BitmapFactory.decodeResource(context.getResources(), R.drawable.hj);

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertices.length*4);
        vbb.order(ByteOrder.nativeOrder());

        vertexBuffer=vbb.asFloatBuffer();
        vertexBuffer.put(vertices);
        vertexBuffer.position(0);

        ByteBuffer tbb=ByteBuffer.allocateDirect(texCoords.length*4);
        tbb.order(ByteOrder.nativeOrder());
        texBuffer=tbb.asFloatBuffer();
        texBuffer.put(texCoords);
        texBuffer.position(0);

    }

    public void loadTexture(GL10 gl){

        IntBuffer textBuffer=IntBuffer.allocate(6);
        gl.glGenTextures(6,textBuffer);
        textures=textBuffer.array();

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[0]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[0],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[1]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[1],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[2]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[2],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[3]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[3],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[4]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[4],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[5]);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,mBitmap[5],0);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);

    }

    public void draw(GL10 gl){

        gl.glFrontFace(GL10.GL_CCW);
        gl.glEnable(GL10.GL_CULL_FACE);
        gl.glCullFace(GL10.GL_BACK);

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexBuffer);
        gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
        gl.glTexCoordPointer(2,GL10.GL_FLOAT,0,texBuffer);

        //front
        gl.glPushMatrix();
        gl.glTranslatef(0.0f, 0.0f, 1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[0]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,4);
        gl.glPopMatrix();

        //left
        gl.glPushMatrix();
        gl.glRotatef(270.0f,0.0f,1.0f,0.0f);
        gl.glTranslatef(0.0f,0.0f,1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[1]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,4);
        gl.glPopMatrix();

        //back
        gl.glPushMatrix();
        gl.glRotatef(180.0f, 0.0f, 1.0f, 0.0f);
        gl.glTranslatef(0.0f, 0.0f, 1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[2]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
        gl.glPopMatrix();

        // right
        gl.glPushMatrix();
        gl.glRotatef(90.0f, 0.0f, 1.0f, 0.0f);
        gl.glTranslatef(0.0f, 0.0f, 1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[3]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
        gl.glPopMatrix();

        // top
        gl.glPushMatrix();
        gl.glRotatef(270.0f, 1.0f, 0.0f, 0.0f);
        gl.glTranslatef(0.0f, 0.0f, 1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[4]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
        gl.glPopMatrix();

        // bottom
        gl.glPushMatrix();
        gl.glRotatef(90.0f, 1.0f, 0.0f, 0.0f);
        gl.glTranslatef(0.0f, 0.0f, 1.0f);
        gl.glBindTexture(GL10.GL_TEXTURE_2D,textures[5]);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
        gl.glPopMatrix();

        gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glDisable(GL10.GL_CULL_FACE);

    }



}

记得在工程drawable下添加6张不同的图片.

渲染器类如下:

package org.pumpkin.pumpkinbasictexture.multexture;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.opengl.GLU;

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

/**
 * Created by Administrator on 2016/5/5.
 */
public class PumpKinTextureRender implements GLSurfaceView.Renderer {

    private MulTextureCube mulTextureCube;
    private float angleTex=0;
    private float speechTex=-1.5f;

    public PumpKinTextureRender(Context context){

        mulTextureCube=new MulTextureCube(context);


    }
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

        mulTextureCube.loadTexture(gl);
        gl.glEnable(GL10.GL_TEXTURE_2D);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f,0.0f,-8.0f);
        gl.glRotatef(angleTex,0.1f,1.0f,0.2f);
        mulTextureCube.draw(gl);

        angleTex+=speechTex;

    }

}

运行效果: