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 : 则采用座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 : 将纹理座标限制在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: