Android OpenGL 教程——窗口初始化&绘制矩形

**Android OpenGL 教程——窗口初始化&绘制矩形**

在本教程中，我们将学习如何使用 Android 的 OpenGL 库来创建一个简单的窗口，并在其中绘制一个矩形。

###1. 创建新项目首先，我们需要在 Android Studio 中创建一个新的项目。选择 "Empty Activity" 模板，填写必要信息，然后点击 "Next" 和 "Finish" 按钮。

###2. 添加 OpenGL 库在项目的 build.gradle 文件中添加以下代码：

groovydependencies {
 implementation 'com.android.support:appcompat-v7:28.0.0'
 implementation 'com.android.support:support-v4:28.0.0'
 implementation 'com.google.android.gms:play-services-base:16.1.0'
 implementation 'com.google.android.gms:play-services-gcm:16.1.0'
 implementation 'com.google.android.gms:play-services-ads:17.2.0'
}

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

public class MyGLSurfaceView extends GLSurfaceView {
 public MyGLSurfaceView(Context context) {
 super(context);
 setEGLContextClientVersion(2.0); // OpenGL ES2.0 setRenderer(new MyRenderer());
 }
}

javaimport android.opengl.GLSurfaceView;
import javax.microedition.khronos.opengles.GL10;

public class MyRenderer implements GLSurfaceView.Renderer {
 @Override public void onSurfaceCreated(GL10 gl, javax.microedition.khronos.opengles.GLU glu) {
 // Initialize OpenGL context gl.glClearColor(0.0f,0.0f,0.0f,1.0f); // Set background color to black }

 @Override public void onSurfaceChanged(GL10 gl, int width, int height) {
 // Update viewport size gl.glViewport(0,0, width, height);
 }

 @Override public void onDrawFrame(GL10 gl) {
 // Draw a rectangle gl.glClear(GL10.GL_COLOR_BUFFER_BIT); // Clear screen gl.glMatrixMode(GL10.GL_PROJECTION);
 gl.glLoadIdentity();
 gl.glOrthof(0.0f,1.0f,0.0f,1.0f, -5.0f,5.0f); // Set up orthographic projection gl.glMatrixMode(GL10.GL_MODELVIEW);
 gl.glLoadIdentity();

 float[] vertices = {
0.2f,0.9f,
0.8f,0.9f,
0.8f,0.1f,
0.2f,0.1f };

 gl.glVertexPointer(2, GL10.GL_FLOAT,0, vertices);

 int[] colors = {
255,0,0, // Red0,255,0, // Green0,0,255, // Blue255,255,0 // Yellow };

 gl.glColorPointer(4, GL10.GL_UNSIGNED_BYTE,0, colors);

 gl.glDrawArrays(GL10.GL_QUADS,0,4);
 }
}

javaimport android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
 @Override protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 MyGLSurfaceView glSurfaceView = new MyGLSurfaceView(this);
 setContentView(glSurfaceView);
 }
}