使用open GL ES 绘制三角形
首先自定义一个GLSurfaceView
class MyGLSurceView extends GLSurfaceView { public MyGLSurceView(Context context, AttributeSet attrs) {
super(context, attrs);
} public MyGLSurceView(Context context) {
super(context);
} }
再定义一个给GLSurfaceView进行渲染的渲染器Renderer,他是GLSurfaceView的内部接口类。
class MyRenderer implements GLSurfaceView.Renderer { @Override
public void onDrawFrame(GL10 gl) {
//清除缓存颜色区域
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
//设置模型视图
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();//加载单位矩阵
//眼睛放置的位置
//GL10 gl, float eyeX, float eyeY, float eyeZ, 眼睛放置的位置
//float centerX, float centerY, float centerZ, 相机放置的位置
//float upX, float upY, float upZ 相机的朝向
GLU.gluLookAt(gl, 0, 0, 5, 0, 0, 0, 0, 1, 0);
//定义三角形的点x,y,z
float[] coords = {
0f,0.5f,0f,
-0.5f,-0.5f,0f,
0.5f,-0.5f,0f
};
//存到内存缓存区
ByteBuffer buffer = ByteBuffer.allocateDirect(coords.length *4);
buffer.order(ByteOrder.nativeOrder());
//放置顶点坐标
FloatBuffer floatBuf = buffer.asFloatBuffer();
floatBuf.put(coords);//将点存放到floatBuffer里面
buffer.position(0);//指针指向0
//制定绘制点的颜色
gl.glColor4f(1f, 0f, 0f, 1f);
//开始绘制点
//3 三维点, type数据类型,0跨度,顶点缓冲区
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, buffer);
//设置绘制三角形
gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3); } @Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
//设置视口区域
gl.glViewport(0, 0, width, height);
//设置绘制模式
gl.glMatrixMode(GL10.GL_PROJECTION);
//设置为单例矩阵
gl.glLoadIdentity();
float ration = (float)width/(float)height;
//设置平截头体 左,右,下,上,近平面,远平面
gl.glFrustumf(-1f, 1f, -ration, ration, 3, 7); } @Override
public void onSurfaceCreated(GL10 gl, EGLConfig arg1) {
//设置清屏颜色
gl.glClearColor(1, 1, 1, 1);
//启动绘制顶点数组
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
} }
public class MainActivity extends Activity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MyGLSurceView glSurceView = new MyGLSurceView(this);
glSurceView.setRenderer(new MyRenderer());
setContentView(glSurceView);
}
}
运行效果图如下: