【Android】第3章（25）示例24--OpenGL绘制功能

分类：C#、Android、VS2015、百度地图应用； 创建日期：2016-02-04 一、简介 百度地图SDK为广大开发者开放了OpenGL绘制接口，帮助开发者在地图上实现更灵活的样式绘制，丰富地图使用效果体验。 二、运行截图 简介：介绍如何使用OpenGL在地图上实现自定义绘制

分类：C#、Android、VS2015、百度地图应用； 创建日期：2016-02-04

一、简介

百度地图SDK为广大开发者开放了OpenGL绘制接口，帮助开发者在地图上实现更灵活的样式绘制，丰富地图使用效果体验。

 

二、运行截图

简介：介绍如何使用OpenGL在地图上实现自定义绘制。

详述：

（1）利用OpenGL绘制基本折线；

（2）利用OpenGL在地图上进行纹理绘制；

本示例运行截图如下：

三、设计步骤

1、添加demo24_opengl.xml文件

在layout文件夹下添加该文件，然后将代码改为下面的内容：

<span style="color: #0000ff;"></span><span style="color: #ff00ff;">xml version="1.0" encoding="utf-8"</span><span style="color: #0000ff;">?></span>
<span style="color: #0000ff;"><span style="color: #800000;">RelativeLayout </span><span style="color: #ff0000;">xmlns:android</span><span style="color: #0000ff;">="http://schemas.android.com/apk/res/android"</span><span style="color: #ff0000;">
    android:layout_width</span><span style="color: #0000ff;">="fill_parent"</span><span style="color: #ff0000;">
    android:layout_height</span><span style="color: #0000ff;">="fill_parent"</span><span style="color: #ff0000;">
    android:orientation</span><span style="color: #0000ff;">="vertical"</span> <span style="color: #0000ff;">></span>
  <span style="color: #0000ff;"><span style="color: #800000;">com.baidu.mapapi.map.TextureMapView
      </span><span style="color: #ff0000;">android:id</span><span style="color: #0000ff;">="@+id/bmapView"</span><span style="color: #ff0000;">
      android:layout_width</span><span style="color: #0000ff;">="match_parent"</span><span style="color: #ff0000;">
      android:layout_height</span><span style="color: #0000ff;">="fill_parent"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">RelativeLayout</span><span style="color: #0000ff;">></span></span></span>

2、添加Demo24OpenGL.cs文件

在SrcSdkDemos文件夹下添加该文件，然后将代码改为下面的内容：

<span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.App;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.OS;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Com.Baidu.Mapapi.Map;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Com.Baidu.Mapapi.Model;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Graphics;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Util;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> System.Collections.Generic;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> javax.Microedition.Khronos.Opengles;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Java.Nio;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Opengl;

</span><span style="color: #0000ff;">namespace</span><span style="color: #000000;"> BdMapV371Demos.SrcSdkDemos
{
    </span><span style="color: #808080;">///</span> <span style="color: #808080;"><summary></summary></span>
    <span style="color: #808080;">///</span><span style="color: #008000;"> 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
    </span><span style="color: #808080;">///</span> <span style="color: #808080;"></span>
    [Activity(Label = <span style="color: #800000;">"</span><span style="color: #800000;">@string/demo_name_opengl</span><span style="color: #800000;">"</span><span style="color: #000000;">)]
    </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">class</span><span style="color: #000000;"> Demo24OpenGL : Activity, BaiduMap.IOnMapDrawFrameCallback
    {
        </span><span style="color: #008000;">//</span><span style="color: #008000;"> 地图相关</span>
        <span style="color: #0000ff;">PRivate</span><span style="color: #000000;"> TextureMapView mMapView;
        </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> BaiduMap mBaiduMap;
        </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> Bitmap bitmap;
        </span><span style="color: #0000ff;">private</span> LatLng latlng1 = <span style="color: #0000ff;">new</span> LatLng(<span style="color: #800080;">39.97923</span>, <span style="color: #800080;">116.357428</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">private</span> LatLng latlng2 = <span style="color: #0000ff;">new</span> LatLng(<span style="color: #800080;">39.94923</span>, <span style="color: #800080;">116.397428</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">private</span> LatLng latlng3 = <span style="color: #0000ff;">new</span> LatLng(<span style="color: #800080;">39.96923</span>, <span style="color: #800080;">116.437428</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">private</span> IList<latlng><span style="color: #000000;"> latLngPolygon;
        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">float</span><span style="color: #000000;">[] vertexs;
        </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> FloatBuffer vertexBuffer;
        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span> textureId = -<span style="color: #800080;">1</span><span style="color: #000000;">;
        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">readonly</span> <span style="color: #0000ff;">string</span> LTAG = <span style="color: #800000;">"</span><span style="color: #800000;">Demo24OpenGL</span><span style="color: #800000;">"</span><span style="color: #000000;">;

        </span><span style="color: #0000ff;">protected</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnCreate(Bundle savedInstanceState)
        {
            </span><span style="color: #0000ff;">base</span><span style="color: #000000;">.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.demo24_opengl);
            mMapView </span>= FindViewById<texturemapview><span style="color: #000000;">(Resource.Id.bmapView);
            mBaiduMap </span>=<span style="color: #000000;"> mMapView.Map;
            latLngPolygon </span>= <span style="color: #0000ff;">new</span> List<latlng><span style="color: #000000;">()
            {
                latlng1,latlng2,latlng3
            };
            mBaiduMap.SetOnMapDrawFrameCallback(</span><span style="color: #0000ff;">this</span><span style="color: #000000;">);
            bitmap </span>=<span style="color: #000000;"> BitmapFactory.DecodeResource(Resources,
                Resource.Drawable.ground_overlay);
        }

        </span><span style="color: #0000ff;">protected</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnPause()
        {
            mMapView.OnPause();
            </span><span style="color: #0000ff;">base</span><span style="color: #000000;">.OnPause();
        }
        </span><span style="color: #0000ff;">protected</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnResume()
        {
            mMapView.OnResume();
            textureId </span>= -<span style="color: #800080;">1</span><span style="color: #000000;">;
            </span><span style="color: #0000ff;">base</span><span style="color: #000000;">.OnResume();
        }

        </span><span style="color: #0000ff;">protected</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnDestroy()
        {
            mMapView.OnDestroy();
            </span><span style="color: #0000ff;">base</span><span style="color: #000000;">.OnDestroy();
        }

        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnMapDrawFrame(IGL10 gl, MapStatus drawingMapStatus)
        {
            </span><span style="color: #0000ff;">if</span> (mBaiduMap.Projection != <span style="color: #0000ff;">null</span><span style="color: #000000;">)
            {
                calPolylinePoint(drawingMapStatus);
                drawPolyline(gl, Color.Argb(</span><span style="color: #800080;">255</span>, <span style="color: #800080;">255</span>, <span style="color: #800080;">0</span>, <span style="color: #800080;">0</span>), vertexBuffer, <span style="color: #800080;">10</span>, <span style="color: #800080;">3</span><span style="color: #000000;">,
                        drawingMapStatus);
                drawTexture(gl, bitmap, drawingMapStatus);
            }
        }
        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> calPolylinePoint(MapStatus mspStatus)
        {
            PointF[] polyPoints </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> PointF[latLngPolygon.Count];
            vertexs </span>= <span style="color: #0000ff;">new</span> <span style="color: #0000ff;">float</span>[<span style="color: #800080;">3</span> *<span style="color: #000000;"> latLngPolygon.Count];
            </span><span style="color: #0000ff;">int</span> i = <span style="color: #800080;">0</span><span style="color: #000000;">;
            </span><span style="color: #0000ff;">foreach</span> (LatLng xy <span style="color: #0000ff;">in</span><span style="color: #000000;"> latLngPolygon)
            {
                polyPoints[i] </span>=<span style="color: #000000;"> mBaiduMap.Projection.ToOpenGLLocation(xy, mspStatus);
                vertexs[i </span>* <span style="color: #800080;">3</span>] =<span style="color: #000000;"> polyPoints[i].X;
                vertexs[i </span>* <span style="color: #800080;">3</span> + <span style="color: #800080;">1</span>] =<span style="color: #000000;"> polyPoints[i].Y;
                vertexs[i </span>* <span style="color: #800080;">3</span> + <span style="color: #800080;">2</span>] = <span style="color: #800080;">0.0f</span><span style="color: #000000;">;
                i</span>++<span style="color: #000000;">;
            }
            </span><span style="color: #0000ff;">for</span> (<span style="color: #0000ff;">int</span> j = <span style="color: #800080;">0</span>; j )
            {
                Log.Debug(LTAG, <span style="color: #800000;">"</span><span style="color: #800000;">vertexs[</span><span style="color: #800000;">"</span> + j + <span style="color: #800000;">"</span><span style="color: #800000;">]: </span><span style="color: #800000;">"</span> +<span style="color: #000000;"> vertexs[j]);
            }
            vertexBuffer </span>=<span style="color: #000000;"> makeFloatBuffer(vertexs);
        }

        </span><span style="color: #0000ff;">private</span> FloatBuffer makeFloatBuffer(<span style="color: #0000ff;">float</span><span style="color: #000000;">[] fs)
        {
            ByteBuffer bb </span>= ByteBuffer.AllocateDirect(fs.Length * <span style="color: #800080;">4</span><span style="color: #000000;">);
            bb.Order(ByteOrder.NativeOrder());
            FloatBuffer fb </span>=<span style="color: #000000;"> bb.AsFloatBuffer();
            fb.Put(fs);
            fb.Position(</span><span style="color: #800080;">0</span><span style="color: #000000;">);
            </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> fb;
        }

        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">void</span> drawPolyline(IGL10 gl, <span style="color: #0000ff;">int</span><span style="color: #000000;"> color, FloatBuffer lineVertexBuffer,
                </span><span style="color: #0000ff;">float</span> lineWidth, <span style="color: #0000ff;">int</span><span style="color: #000000;"> pointSize, MapStatus drawingMapStatus)
        {

            gl.GlEnable(GL10.GlBlend);
            gl.GlEnableClientState(GL10.GlVertexArray);

            gl.GlBlendFunc(GL10.GlSrcAlpha, GL10.GlOneMinusSrcAlpha);

            </span><span style="color: #0000ff;">float</span> colorA = Color.GetAlphaComponent(color) /<span style="color: #000000;"> 255f;
            </span><span style="color: #0000ff;">float</span> colorR = Color.GetRedComponent(color) /<span style="color: #000000;"> 255f;
            </span><span style="color: #0000ff;">float</span> colorG = Color.GetGreenComponent(color) /<span style="color: #000000;"> 255f;
            </span><span style="color: #0000ff;">float</span> colorB = Color.GetBlueComponent(color) /<span style="color: #000000;"> 255f;

            gl.GlVertexPointer(</span><span style="color: #800080;">3</span>, GL10.GlFloat, <span style="color: #800080;">0</span><span style="color: #000000;">, lineVertexBuffer);
            gl.GlColor4f(colorR, colorG, colorB, colorA);
            gl.GlLineWidth(lineWidth);
            gl.GlDrawArrays(GL10.GlLineStrip, </span><span style="color: #800080;">0</span><span style="color: #000000;">, pointSize);

            gl.GlDisable(GL10.GlBlend);
            gl.GlDisableClientState(GL10.GlVertexArray);
        }

        </span><span style="color: #808080;">///</span> <span style="color: #808080;"><summary></summary></span>
        <span style="color: #808080;">///</span><span style="color: #008000;"> 使用opengl坐标绘制
        </span><span style="color: #808080;">///</span> <span style="color: #808080;"></span>
        <span style="color: #808080;">///</span> <span style="color: #808080;"><param name="gl"></span>
        <span style="color: #808080;">///</span> <span style="color: #808080;"><param name="bitmap"></span>
        <span style="color: #808080;">///</span> <span style="color: #808080;"><param name="drawingMapStatus"></span>
        <span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> drawTexture(IGL10 gl, Bitmap bitmap, MapStatus drawingMapStatus)
        {
            PointF p1 </span>=<span style="color: #000000;"> mBaiduMap.Projection.ToOpenGLLocation(latlng2,
                    drawingMapStatus);
            PointF p2 </span>=<span style="color: #000000;"> mBaiduMap.Projection.ToOpenGLLocation(latlng3,
                    drawingMapStatus);
            ByteBuffer byteBuffer </span>= ByteBuffer.AllocateDirect(<span style="color: #800080;">4</span> * <span style="color: #800080;">3</span> * <span style="color: #800080;">4</span><span style="color: #000000;">);
            byteBuffer.Order(ByteOrder.NativeOrder());
            FloatBuffer vertices </span>=<span style="color: #000000;"> byteBuffer.AsFloatBuffer();
            vertices.Put(</span><span style="color: #0000ff;">new</span> <span style="color: #0000ff;">float</span>[] { p1.X, p1.Y, <span style="color: #800080;">0.0f</span>, p2.X, p1.Y, <span style="color: #800080;">0.0f</span><span style="color: #000000;">, p1.X,
                p2.Y, </span><span style="color: #800080;">0.0f</span>, p2.X, p2.Y, <span style="color: #800080;">0.0f</span><span style="color: #000000;"> });

            ByteBuffer indicesBuffer </span>= ByteBuffer.AllocateDirect(<span style="color: #800080;">6</span> * <span style="color: #800080;">2</span><span style="color: #000000;">);
            indicesBuffer.Order(ByteOrder.NativeOrder());
            ShortBuffer indices </span>=<span style="color: #000000;"> indicesBuffer.AsShortBuffer();
            indices.Put(</span><span style="color: #0000ff;">new</span> <span style="color: #0000ff;">short</span>[] { <span style="color: #800080;">0</span>, <span style="color: #800080;">1</span>, <span style="color: #800080;">2</span>, <span style="color: #800080;">1</span>, <span style="color: #800080;">2</span>, <span style="color: #800080;">3</span><span style="color: #000000;"> });

            ByteBuffer textureBuffer </span>= ByteBuffer.AllocateDirect(<span style="color: #800080;">4</span> * <span style="color: #800080;">2</span> * <span style="color: #800080;">4</span><span style="color: #000000;">);
            textureBuffer.Order(ByteOrder.NativeOrder());
            FloatBuffer texture </span>=<span style="color: #000000;"> textureBuffer.AsFloatBuffer();
            texture.Put(</span><span style="color: #0000ff;">new</span> <span style="color: #0000ff;">float</span>[] { <span style="color: #800080;">0</span><span style="color: #000000;">, 1f, 1f, 1f, 0f, 0f, 1f, 0f });

            indices.Position(</span><span style="color: #800080;">0</span><span style="color: #000000;">);
            vertices.Position(</span><span style="color: #800080;">0</span><span style="color: #000000;">);
            texture.Position(</span><span style="color: #800080;">0</span><span style="color: #000000;">);

            </span><span style="color: #008000;">//</span><span style="color: #008000;"> 生成纹理</span>
            <span style="color: #0000ff;">if</span> (textureId == -<span style="color: #800080;">1</span><span style="color: #000000;">)
            {
                </span><span style="color: #0000ff;">int</span>[] textureIds = <span style="color: #0000ff;">new</span> <span style="color: #0000ff;">int</span>[<span style="color: #800080;">1</span><span style="color: #000000;">];
                gl.GlGenTextures(</span><span style="color: #800080;">1</span>, textureIds, <span style="color: #800080;">0</span><span style="color: #000000;">);
                textureId </span>= textureIds[<span style="color: #800080;">0</span><span style="color: #000000;">];
                Log.Debug(LTAG, </span><span style="color: #800000;">"</span><span style="color: #800000;">textureId: </span><span style="color: #800000;">"</span> +<span style="color: #000000;"> textureId);
                gl.GlBindTexture(GL10.GlTexture2d, textureId);
                GLUtils.TexImage2D(GL10.GlTexture2d, </span><span style="color: #800080;">0</span>, bitmap, <span style="color: #800080;">0</span><span style="color: #000000;">);
                gl.GlTexParameterf(GL10.GlTexture2d, GL10.GlTextureMinFilter, GL10.GlNearest);
                gl.GlTexParameterf(GL10.GlTexture2d, GL10.GlTextureMagFilter, GL10.GlNearest);
                gl.GlBindTexture(GL10.GlTexture2d, </span><span style="color: #800080;">0</span><span style="color: #000000;">);
            }

            gl.GlEnable(GL10.GlTexture2d);
            gl.GlEnableClientState(GL10.GlVertexArray);
            gl.GlEnableClientState(GL10.GlTextureCoordArray);
            gl.GlEnable(GL10.GlBlend);
            gl.GlBlendFunc(GL10.GlSrcAlpha, GL10.GlOneMinusSrcAlpha);
            gl.GlColor4f(</span><span style="color: #800080;">1.0f</span>, <span style="color: #800080;">1.0f</span>, <span style="color: #800080;">1.0f</span>, <span style="color: #800080;">1.0f</span><span style="color: #000000;">);

            </span><span style="color: #008000;">//</span><span style="color: #008000;"> 绑定纹理ID</span>
<span style="color: #000000;">            gl.GlBindTexture(GL10.GlTexture2d, textureId);
            gl.GlVertexPointer(</span><span style="color: #800080;">3</span>, GL10.GlFloat, <span style="color: #800080;">0</span><span style="color: #000000;">, vertices);
            gl.GlTexCoordPointer(</span><span style="color: #800080;">2</span>, GL10.GlFloat, <span style="color: #800080;">0</span><span style="color: #000000;">, texture);
            gl.GlDrawElements(GL10.GlTriangleStrip, </span><span style="color: #800080;">6</span><span style="color: #000000;">, GL10.GlUnsignedShort, indices);
            gl.GlDisable(GL10.GlTexture2d);
            gl.GlDisableClientState(GL10.GlVertexArray);
            gl.GlDisableClientState(GL10.GlTextureCoordArray);
            gl.GlDisable(GL10.GlBlend);
        }
    }
}</span></latlng></texturemapview></latlng>

3、修改MainActivity.cs文件

在MainActivity.cs文件的demos字段定义中，去掉【示例24】下面的注释。

运行观察效果。