java实现OpenGL ES纹理映射的方法

package net.obviam.opengl;import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.opengles.GL10;import android.content.Context;import android.opengl.GLU;import android.opengl.GLSurfaceView.Renderer;public class GlRenderer implements Renderer {  private Square   square;   // the square  private Context   context;  /** Constructor to set the handed over context */  public GlRenderer(Context context) {    this.context = context;    // initialise the square    this.square = new Square();  }  @Override  public void onDrawFrame(GL10 gl) {    // clear Screen and Depth Buffer    gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);    // Reset the Modelview Matrix    gl.glLoadIdentity();    // Drawing    gl.glTranslatef(0.0f, 0.0f, -5.0f);    // move 5 units INTO the screen    // is the same as moving the camera 5 units away//   gl.glScalef(0.5f, 0.5f, 0.5f);// scale the square to 50% // otherwise it will be too large    square.draw(gl); // Draw the triangle  }  @Override  public void onSurfaceChanged(GL10 gl, int width, int height) {    if(height == 0) { //Prevent A Divide By Zero By      height = 1; //Making Height Equal One    }    gl.glViewport(0, 0, width, height); //Reset The Current Viewport    gl.glMatrixMode(GL10.GL_PROJECTION); //Select The Projection Matrix    gl.glLoadIdentity(); //Reset The Projection Matrix    //Calculate The Aspect Ratio Of The Window    GLU.gluPerspective(gl, 45.0f, (float)width / (float)height, 0.1f, 100.0f);    gl.glMatrixMode(GL10.GL_MODELVIEW);    //Select The Modelview Matrix    gl.glLoadIdentity(); //Reset The Modelview Matrix  }  @Override  public void onSurfaceCreated(GL10 gl, EGLConfig config) {    // Load the texture for the square    square.loadGLTexture(gl, this.context);    gl.glEnable(GL10.GL_TEXTURE_2D); //Enable Texture Mapping ( NEW )    gl.glShadeModel(GL10.GL_SMOOTH); //Enable Smooth Shading    gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f); //Black Background    gl.glClearDepthf(1.0f); //Depth Buffer Setup    gl.glEnable(GL10.GL_DEPTH_TEST); //Enables Depth Testing    gl.glDepthFunc(GL10.GL_LEQUAL); //The Type Of Depth Testing To Do    //Really Nice Perspective Calculations    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);   }}

package net.obviam.opengl;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.FloatBuffer;import javax.microedition.khronos.opengles.GL10;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.opengl.GLUtils;public class Square {  private FloatBuffer vertexBuffer;  // buffer holding the vertices  private float vertices[] = {      -1.0f, -1.0f, 0.0f,    // V1 - bottom left      -1.0f, 1.0f, 0.0f,    // V2 - top left       1.0f, -1.0f, 0.0f,    // V3 - bottom right       1.0f, 1.0f, 0.0f     // V4 - top right  };  private FloatBuffer textureBuffer; // buffer holding the texture coordinates  private float texture[] = {           // Mapping coordinates for the vertices      0.0f, 1.0f,   // top left   (V2)      0.0f, 0.0f,   // bottom left (V1)      1.0f, 1.0f,   // top right  (V4)      1.0f, 0.0f   // bottom right (V3)  };  /** The texture pointer */  private int[] textures = new int[1];  public Square() {    // a float has 4 bytes so we allocate for each coordinate 4 bytes    ByteBuffer byteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);    byteBuffer.order(ByteOrder.nativeOrder());    // allocates the memory from the byte buffer    vertexBuffer = byteBuffer.asFloatBuffer();    // fill the vertexBuffer with the vertices    vertexBuffer.put(vertices);    // set the cursor position to the beginning of the buffer    vertexBuffer.position(0);    byteBuffer = ByteBuffer.allocateDirect(texture.length * 4);    byteBuffer.order(ByteOrder.nativeOrder());    textureBuffer = byteBuffer.asFloatBuffer();    textureBuffer.put(texture);    textureBuffer.position(0);  }  /**   * Load the texture for the square   * @param gl   * @param context   */  public void loadGLTexture(GL10 gl, Context context) {    // loading texture    Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.android);    // generate one texture pointer    gl.glGenTextures(1, textures, 0);    // ...and bind it to our array    gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);    // create nearest filtered texture    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);    //Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE//   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);    // Use Android GLUtils to specify a two-dimensional texture image from our bitmap     GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);    // Clean up    bitmap.recycle();  }  /** The draw method for the square with the GL context */  public void draw(GL10 gl) {    // bind the previously generated texture    gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);    // Point to our buffers    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);    // Set the face rotation    gl.glFrontFace(GL10.GL_CW);    // Point to our vertex buffer    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);    gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);    // Draw the vertices as triangle strip    gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);    //Disable the client state before leaving    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);  }}

package net.obviam.opengl;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.FloatBuffer;import javax.microedition.khronos.opengles.GL10;public class Triangle {  private FloatBuffer vertexBuffer;  // buffer holding the vertices  private float vertices[] = {      -0.5f, -0.5f, 0.0f,    // V1 - first vertex (x,y,z)       0.5f, -0.5f, 0.0f,    // V2 - second vertex       0.0f, 0.5f, 0.0f     // V3 - third vertex//      1.0f, 0.5f, 0.0f     // V3 - third vertex  };  public Triangle() {    // a float has 4 bytes so we allocate for each coordinate 4 bytes    ByteBuffer vertexByteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);    vertexByteBuffer.order(ByteOrder.nativeOrder());    // allocates the memory from the byte buffer    vertexBuffer = vertexByteBuffer.asFloatBuffer();    // fill the vertexBuffer with the vertices    vertexBuffer.put(vertices);    // set the cursor position to the beginning of the buffer    vertexBuffer.position(0);  }  /** The draw method for the triangle with the GL context */  public void draw(GL10 gl) {    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);    // set the colour for the background//   gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);    // to show the color (paint the screen) we need to clear the color buffer//   gl.glClear(GL10.GL_COLOR_BUFFER_BIT);    // set the colour for the triangle    gl.glColor4f(0.0f, 1.0f, 0.0f, 0.5f);    // Point to our vertex buffer    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);    // Draw the vertices as triangle strip    gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);    //Disable the client state before leaving    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);  }}

package net.obviam.opengl;import android.app.Activity;import android.opengl.GLSurfaceView;import android.os.Bundle;import android.view.Window;import android.view.WindowManager;public class Run extends Activity {  /** The OpenGL view */  private GLSurfaceView glSurfaceView;  /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    // requesting to turn the title OFF    requestWindowFeature(Window.FEATURE_NO_TITLE);    // making it full screen    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,        WindowManager.LayoutParams.FLAG_FULLSCREEN);    // Initiate the Open GL view and    // create an instance with this activity    glSurfaceView = new GLSurfaceView(this);    // set our renderer to be the main renderer with    // the current activity context    glSurfaceView.setRenderer(new GlRenderer(this));    setContentView(glSurfaceView);  }  /**   * Remember to resume the glSurface   */  @Override  protected void onResume() {    super.onResume();    glSurfaceView.onResume();  }  /**   * Also pause the glSurface   */  @Override  protected void onPause() {    super.onPause();    glSurfaceView.onPause();  }}