【Android】第3章（25）示例24--OpenGL绘制功能

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >  <com.baidu.mapapi.map.TextureMapView      android:id="@+id/bmapView"      android:layout_width="match_parent"      android:layout_height="fill_parent" /></RelativeLayout>

using Android.App;using Android.OS;using Com.Baidu.Mapapi.Map;using Com.Baidu.Mapapi.Model;using Android.Graphics;using Android.Util;using System.Collections.Generic;using javax.Microedition.Khronos.Opengles;using Java.Nio;using Android.Opengl;namespace BdMapV371Demos.SrcSdkDemos{    /// <summary>    /// 此demo用来展示如何在地图绘制的每帧中再额外绘制一些用户自己的内容    /// </summary>    [Activity(Label = "@string/demo_name_opengl")]    public class Demo24OpenGL : Activity, BaiduMap.IOnMapDrawFrameCallback    {        // 地图相关        PRivate TextureMapView mMapView;        private BaiduMap mBaiduMap;        private Bitmap bitmap;        private LatLng latlng1 = new LatLng(39.97923, 116.357428);        private LatLng latlng2 = new LatLng(39.94923, 116.397428);        private LatLng latlng3 = new LatLng(39.96923, 116.437428);        private IList<LatLng> latLngPolygon;        private float[] vertexs;        private FloatBuffer vertexBuffer;        private int textureId = -1;        private readonly string LTAG = "Demo24OpenGL";        protected override void OnCreate(Bundle savedInstanceState)        {            base.OnCreate(savedInstanceState);            SetContentView(Resource.Layout.demo24_opengl);            mMapView = FindViewById<TextureMapView>(Resource.Id.bmapView);            mBaiduMap = mMapView.Map;            latLngPolygon = new List<LatLng>()            {                latlng1,latlng2,latlng3            };            mBaiduMap.SetOnMapDrawFrameCallback(this);            bitmap = BitmapFactory.DecodeResource(Resources,                Resource.Drawable.ground_overlay);        }        protected override void OnPause()        {            mMapView.OnPause();            base.OnPause();        }        protected override void OnResume()        {            mMapView.OnResume();            textureId = -1;            base.OnResume();        }        protected override void OnDestroy()        {            mMapView.OnDestroy();            base.OnDestroy();        }        public void OnMapDrawFrame(IGL10 gl, MapStatus drawingMapStatus)        {            if (mBaiduMap.Projection != null)            {                calPolylinePoint(drawingMapStatus);                drawPolyline(gl, Color.Argb(255, 255, 0, 0), vertexBuffer, 10, 3,                        drawingMapStatus);                drawTexture(gl, bitmap, drawingMapStatus);            }        }        public void calPolylinePoint(MapStatus mspStatus)        {            PointF[] polyPoints = new PointF[latLngPolygon.Count];            vertexs = new float[3 * latLngPolygon.Count];            int i = 0;            foreach (LatLng xy in latLngPolygon)            {                polyPoints[i] = mBaiduMap.Projection.ToOpenGLLocation(xy, mspStatus);                vertexs[i * 3] = polyPoints[i].X;                vertexs[i * 3 + 1] = polyPoints[i].Y;                vertexs[i * 3 + 2] = 0.0f;                i++;            }            for (int j = 0; j < vertexs.Length; j++)            {                Log.Debug(LTAG, "vertexs[" + j + "]: " + vertexs[j]);            }            vertexBuffer = makeFloatBuffer(vertexs);        }        private FloatBuffer makeFloatBuffer(float[] fs)        {            ByteBuffer bb = ByteBuffer.AllocateDirect(fs.Length * 4);            bb.Order(ByteOrder.NativeOrder());            FloatBuffer fb = bb.AsFloatBuffer();            fb.Put(fs);            fb.Position(0);            return fb;        }        private void drawPolyline(IGL10 gl, int color, FloatBuffer lineVertexBuffer,                float lineWidth, int pointSize, MapStatus drawingMapStatus)        {            gl.GlEnable(GL10.GlBlend);            gl.GlEnableClientState(GL10.GlVertexArray);            gl.GlBlendFunc(GL10.GlSrcAlpha, GL10.GlOneMinusSrcAlpha);            float colorA = Color.GetAlphaComponent(color) / 255f;            float colorR = Color.GetRedComponent(color) / 255f;            float colorG = Color.GetGreenComponent(color) / 255f;            float colorB = Color.GetBlueComponent(color) / 255f;            gl.GlVertexPointer(3, GL10.GlFloat, 0, lineVertexBuffer);            gl.GlColor4f(colorR, colorG, colorB, colorA);            gl.GlLineWidth(lineWidth);            gl.GlDrawArrays(GL10.GlLineStrip, 0, pointSize);            gl.GlDisable(GL10.GlBlend);            gl.GlDisableClientState(GL10.GlVertexArray);        }        /// <summary>        /// 使用opengl坐标绘制        /// </summary>        /// <param name="gl"></param>        /// <param name="bitmap"></param>        /// <param name="drawingMapStatus"></param>        public void drawTexture(IGL10 gl, Bitmap bitmap, MapStatus drawingMapStatus)        {            PointF p1 = mBaiduMap.Projection.ToOpenGLLocation(latlng2,                    drawingMapStatus);            PointF p2 = mBaiduMap.Projection.ToOpenGLLocation(latlng3,                    drawingMapStatus);            ByteBuffer byteBuffer = ByteBuffer.AllocateDirect(4 * 3 * 4);            byteBuffer.Order(ByteOrder.NativeOrder());            FloatBuffer vertices = byteBuffer.AsFloatBuffer();            vertices.Put(new float[] { p1.X, p1.Y, 0.0f, p2.X, p1.Y, 0.0f, p1.X,                p2.Y, 0.0f, p2.X, p2.Y, 0.0f });            ByteBuffer indicesBuffer = ByteBuffer.AllocateDirect(6 * 2);            indicesBuffer.Order(ByteOrder.NativeOrder());            ShortBuffer indices = indicesBuffer.AsShortBuffer();            indices.Put(new short[] { 0, 1, 2, 1, 2, 3 });            ByteBuffer textureBuffer = ByteBuffer.AllocateDirect(4 * 2 * 4);            textureBuffer.Order(ByteOrder.NativeOrder());            FloatBuffer texture = textureBuffer.AsFloatBuffer();            texture.Put(new float[] { 0, 1f, 1f, 1f, 0f, 0f, 1f, 0f });            indices.Position(0);            vertices.Position(0);            texture.Position(0);            // 生成纹理            if (textureId == -1)            {                int[] textureIds = new int[1];                gl.GlGenTextures(1, textureIds, 0);                textureId = textureIds[0];                Log.Debug(LTAG, "textureId: " + textureId);                gl.GlBindTexture(GL10.GlTexture2d, textureId);                GLUtils.TexImage2D(GL10.GlTexture2d, 0, bitmap, 0);                gl.GlTexParameterf(GL10.GlTexture2d, GL10.GlTextureMinFilter, GL10.GlNearest);                gl.GlTexParameterf(GL10.GlTexture2d, GL10.GlTextureMagFilter, GL10.GlNearest);                gl.GlBindTexture(GL10.GlTexture2d, 0);            }            gl.GlEnable(GL10.GlTexture2d);            gl.GlEnableClientState(GL10.GlVertexArray);            gl.GlEnableClientState(GL10.GlTextureCoordArray);            gl.GlEnable(GL10.GlBlend);            gl.GlBlendFunc(GL10.GlSrcAlpha, GL10.GlOneMinusSrcAlpha);            gl.GlColor4f(1.0f, 1.0f, 1.0f, 1.0f);            // 绑定纹理ID            gl.GlBindTexture(GL10.GlTexture2d, textureId);            gl.GlVertexPointer(3, GL10.GlFloat, 0, vertices);            gl.GlTexCoordPointer(2, GL10.GlFloat, 0, texture);            gl.GlDrawElements(GL10.GlTriangleStrip, 6, GL10.GlUnsignedShort, indices);            gl.GlDisable(GL10.GlTexture2d);            gl.GlDisableClientState(GL10.GlVertexArray);            gl.GlDisableClientState(GL10.GlTextureCoordArray);            gl.GlDisable(GL10.GlBlend);        }    }}