java实现OpenGL ES纹理映射的方法

java实现OpenGL ES纹理映射的方法

本文实例讲述了java实现OpenGL ES纹理映射的方法。分享给大家供大家参考。具体如下：

1. GlRenderer.java文件：

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);

}

}

2. Square.java文件：

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 http:/// 3);

//Disable the client state before leaving

gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

}

}

3. Triangle.java文件：

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);

}

}

4. Run.java文件：

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);

}

NlVDjTU/**

* 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();

}

}

希望本文所述对大家的java程序设计有所帮助。

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