openGL 简单demo

画一个三角形一个正方形

openGL 简单demo_第1张图片

建立渲染器类

package com.example.demo_opengl;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.IntBuffer;import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.opengles.GL10;import android.opengl.GLSurfaceView.Renderer;public class MyRenderer implements Renderer {int one = 0x10000; // 一定要16进制,16int one1 = 0x10000 / 2; // 一定要16进制,16private IntBuffer triangleBuffer; // 缓冲三角形private int[] triangleVertices = new int[] { 0, one, 0, -one, -one, 0, one,-one, 0 }; // 三角形的三个顶点,上,左下,右下// 正方形private IntBuffer quaterBuffer;private int[] quaterVertices = new int[] { one, one, 0, -one, one, 0, one,-one, 0, -one, -one, 0 }; // 四边形,右上,左上,右下,左下// 正方形2private IntBuffer quaterBuffer2;private int[] quaterVertices2 = new int[] { one1, one1, 10, -one1, one1,10, one1, -one1, 10, -one1, -one1, 10 }; // 四边形,右上,左上,右下,左下@Overridepublic void onSurfaceCreated(GL10 gl, EGLConfig config) {// 初始化三角形// ByteBuffer位于java.nio包中，目前提供了Java基本类型中除Boolean外其他类型的缓冲类型，比如ByteBuffer、DoubleBuffer、FloatBuffer、IntBuffer、LongBuffer和ShortBuffer// 。一个int类占4字节所以要*4ByteBuffer byteBuffer = ByteBuffer.allocateDirect(triangleVertices.length * 4); // 为缓冲区分配空间byteBuffer.order(ByteOrder.nativeOrder());triangleBuffer = byteBuffer.asIntBuffer();triangleBuffer.put(triangleVertices); // 顶点坐标放入intbuffertriangleBuffer.position(0); // 缓冲区指针指向第一个字节位置// 画正方形----------------------------------------------byteBuffer = ByteBuffer.allocateDirect(quaterVertices.length * 4);byteBuffer.order(ByteOrder.nativeOrder());quaterBuffer = byteBuffer.asIntBuffer();quaterBuffer.put(quaterVertices);quaterBuffer.position(0);// 画正方形2----------------------------------------------byteBuffer = ByteBuffer.allocateDirect(quaterVertices2.length * 4);byteBuffer.order(ByteOrder.nativeOrder());quaterBuffer2 = byteBuffer.asIntBuffer();quaterBuffer2.put(quaterVertices2);quaterBuffer2.position(0);}@Overridepublic void onSurfaceChanged(GL10 gl, int width, int height) {// 改变时float ratio = (float) width / height;// OpenGL场景大小gl.glViewport(0, 0, width, height);// 投影矩阵gl.glMatrixMode(GL10.GL_PROJECTION);// 重置投影矩阵gl.glLoadIdentity();// x,y,z轴可以设置的最远距离gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);// 选择模型观察矩阵gl.glMatrixMode(GL10.GL_MODELVIEW);// 重置模型观察矩阵gl.glLoadIdentity();}@Overridepublic void onDrawFrame(GL10 gl) {// 画三角形**************************gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); // 设置这个顶点gl.glLoadIdentity();gl.glTranslatef(1.5f, 0.0f, -6.0f); // 右移1.5,移入屏幕6gl.glVertexPointer(3, GL10.GL_FIXED, 0, triangleBuffer); // 设置三角形顶点坐标(维度,顶点类型,步长,缓存)gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3); // 绘制三角形// 画正方形1********************************//gl.glLoadIdentity();//gl.glTranslatef(-1.0f, 0.0f, -6.0f); // 左移2,移入屏幕6////gl.glVertexPointer(3, GL10.GL_FIXED, 0, quaterBuffer);////gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4); // GL_TRIANGLE_STRIP规则绘制四边形// gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4); //GL_TRIANGLE_FAN规则绘制四边形// 画正方形2********************************gl.glLoadIdentity();//刷新,重置观察矩阵gl.glTranslatef(-4.0f, 0.0f, -6.0f); // 左移4.0,移入屏幕6gl.glVertexPointer(3, GL10.GL_FIXED, 0, quaterBuffer2);gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4); // GL_TRIANGLE_STRIP规则绘制四边形// gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4); //GL_TRIANGLE_FAN规则绘制四边形gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); // 关闭顶点设置}}

在主函数中调用

1.新建GLSurfaceView

2.新建渲染器类MyRenderer()

3.view加载渲染器并显示

package com.example.demo_opengl;import android.opengl.GLSurfaceView;import android.opengl.GLSurfaceView.Renderer;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.MenuItem;import android.support.v4.app.NavUtils;public class MainActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// 新建GLSurfaceView类,渲染器类,载入GLSurfaceView类GLSurfaceView glSurfaceView = new GLSurfaceView(this);Renderer myRenderer = new MyRenderer();glSurfaceView.setRenderer(myRenderer);setContentView(glSurfaceView);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.activity_main, menu);return true;}}

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