OpenGL学习（1）基本概述

OpenGL学习（1）基本概述

(1)重写Rendar（渲染器）， 重写三个方法：

a、onSurfaceCreated(GL10 gl, EGLConfig config);
b、onSurfaceChanged(GL10 gl, int width, int height);
c、 onDrawFrame(GL10 gl);

package com.example.mychapter2;

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

import android.opengl.GLU;
import android.opengl.GLSurfaceView.Renderer;

public class GLRender implements Renderer
{
public void onDrawFrame(GL10 gl)
{
// TODO Auto-generated method stub

// 首先清理屏幕
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

// 设置模型视图矩阵
gl.glMatrixMode(GL10.GL_MODELVIEW);

// 重置矩阵
gl.glLoadIdentity();

// 视点变换
GLU.gluLookAt(gl, 0, 0, 3, 0, 0, 0, 0, 1, 0);

// ...

}

public void onSurfaceChanged(GL10 gl, int width, int height)
{
// TODO Auto-generated method stub

float ratio = (float) width / height;

// 设置视口(OpenGL场景的大小)
gl.glViewport(0, 0, width, height);

// 设置投影矩阵为透视投影
gl.glMatrixMode(GL10.GL_PROJECTION);

// 重置投影矩阵（置为单位矩阵）
gl.glLoadIdentity();

// 创建一个透视投影矩阵（设置视口大小）
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
}

public void onSurfaceCreated(GL10 gl, EGLConfig config)
{
// TODO Auto-generated method stub

// 告诉系统需要对透视进行修正
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);

// 设置清理屏幕的颜色
gl.glClearColor(0, 0, 0, 1);

// 启用深度缓存
gl.glEnable(GL10.GL_DEPTH_TEST);
}

}

(2)创建一个GLSurfaceView

package com.example.mychapter2;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;

public class ChapterMain extends Activity
{
private GLSurfaceView mGLSurfaceView;

/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);

// 实例化GLSurfaceView
mGLSurfaceView = new GLSurfaceView(this);

// 设置渲染器
mGLSurfaceView.setRenderer(new GLRender());

setContentView(mGLSurfaceView);
}

protected void onResume()
{
super.onResume();
mGLSurfaceView.onResume();
}

protected void onPause()
{
super.onPause();
mGLSurfaceView.onPause();
}
}