3D绘图之OpenGL ES

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1.编写一个实现Renderer接口的类

onSurfaceChanged:设置视口大小,设置投影类型,矩阵模式,切换投影类型等

onSurfaceCreated:一些初始化工作,如设置顶点坐标的值.

onDrawFrame:对开关的操作,绘制3D图形,设置顶点坐标等

 class RectangleRender implements GLSurfaceView.Renderer{        //定义顶点        int one=0x10000;        IntBuffer rectangleBuffer;        int[] rectangleVertices=new int[] {                -one,-one,0,                -one,one,0,                one,-one,0,                one,one,0,        };        @Override        public void onSurfaceCreated(GL10 gl, EGLConfig config) {            //为ByteBuffer对象分配内存空间            ByteBuffer byteBuffer=ByteBuffer.allocateDirect(rectangleVertices.length*4);            //按本地字节顺序使用字节数据            byteBuffer.order(ByteOrder.nativeOrder());            //将ByteBuffer转换成intBuffer对象            rectangleBuffer=byteBuffer.asIntBuffer();            //将定义顶点坐标的int数组放到intBuffer对象中            rectangleBuffer.put(rectangleVertices);            //将IntBuffer对象的内部指针移到第1个字节的位置            rectangleBuffer.position(0);     }        @Override        public void onSurfaceChanged(GL10 gl, int width, int height) {            //计算视口宽度与高度比            float ratio=width/height;            //设置视口大小            gl.glViewport(0,0,width,height);            //改变矩阵模式为投影模式            gl.glMatrixMode(GL10.GL_FOG_MODE);            //将当前矩阵设为单位矩阵            gl.glLoadIdentity();            //设置当前的投影类型为透视投影            gl.glFrustumf(-ratio,ratio,1,1,1,10);            //改变矩阵模式为模型视图矩阵            gl.glMatrixMode(GL10.GL_MODELVIEW);        }        @Override        public void onDrawFrame(GL10 gl) {            //必须清楚屏幕,否则不会清除上次的视图            gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BITS);            //允许使用顶点方式绘制图形            gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);            //将当前矩阵设为单位矩阵            gl.glLoadIdentity();            //将当前位置向z轴负方向移6个单位            gl.glTranslatef(0,0,-6);            //旋转90度            gl.glRotatef(90,0,1,0);            //装载用于绘制图形的顶点坐标//            gl.glVertexPointer(3,GL10.GL_FIXED,0,rete);            //绘制图形            gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,4);            //禁止使用顶点方式绘制图形            gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);         }    }

eg:绘制三角形

1.Triangle类

package com.gst.user.application;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.IntBuffer;import javax.microedition.khronos.opengles.GL10;/** * Created by user on 1/5/16. */public class Triangle {    int one = 0x10000;    private IntBuffer triangleBuffer;    private int[] triangleVertices = new int[]            { 0, one, 0, -one, -one, 0, one, -one, 0 };    public Triangle()    {        ByteBuffer byteBuffer = ByteBuffer.allocateDirect(triangleVertices.length * 4);        byteBuffer.order(ByteOrder.nativeOrder());        triangleBuffer = byteBuffer.asIntBuffer();        triangleBuffer.put(triangleVertices);        triangleBuffer.position(0);    }    public void drawSelf(GL10 gl){        gl.glVertexPointer(3,GL10.GL_FIXED,0,triangleBuffer);        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 3);        gl.glRotatef(180, 0, 0, 1);        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 3);    }}

2.TriangleSurfaceView

package com.gst.user.application;import android.opengl.GLSurfaceView;import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.opengles.GL10;/** * Created by user on 1/5/16. */public class TriangleSurfaceView implements GLSurfaceView.Renderer{    Triangle triangle;    int angle1=0;    int angle2=0;    @Override    public void onSurfaceCreated(GL10 gl, EGLConfig config) {        triangle=new Triangle();    }    @Override    public void onSurfaceChanged(GL10 gl, int width, int height) {        float ratio=(float)width/height;        gl.glViewport(0,0,width,height);        gl.glMatrixMode(GL10.GL_PROJECTION);        gl.glLoadIdentity();        gl.glFrustumf(-ratio * 2, ratio * 2, -2, 2, 1, 10);        gl.glMatrixMode(GL10.GL_MODELVIEW);    }    @Override    public void onDrawFrame(GL10 gl) {        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);        gl.glLoadIdentity();        gl.glTranslatef(0, 0, -2);        gl.glRotatef(angle1++, 0, 0, 1);        triangle.drawSelf(gl);        gl.glLoadIdentity();        angle2-=2;        gl.glRotatef(angle2, 0, 0, 1);        gl.glTranslatef(-3, 0, -4);        gl.glRotatef(45, 0, 0, 1);        triangle.drawSelf(gl);        gl.glLoadIdentity();        gl.glRotatef(angle2, 0, 0, 1);        gl.glTranslatef(3, 0, -4);        gl.glRotatef(45, 0, 0, 1);        triangle.drawSelf(gl);        gl.glLoadIdentity();        gl.glRotatef(angle2, 0, 0, 1);        gl.glTranslatef(0,3,-4);        gl.glRotatef(45,0,0,1);        triangle.drawSelf(gl);        gl.glLoadIdentity();        gl.glRotatef(angle2, 0, 0, 1);        gl.glTranslatef(0,-3,-4);        gl.glRotatef(45,0,0,1);        triangle.drawSelf(gl);        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);    }}

3.在Activity的onCreate方法中显示

 GLSurfaceView glSurfaceView=new GLSurfaceView(this); glSurfaceView.setRenderer(new TriangleSurfaceView()); setContentView(glSurfaceView);

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