android地图sdk | 百度地图api sdk-凯发k8官方旗舰厅

百度地图sdk为开发者开放了opengl绘制接口，以帮助开发者在地图上实现灵活的样式绘制，丰富地图的显示效果和使用体验。
自v4.2.0起，百度地图sdk支持opengles 2.0，请开发者调用onmapdrawframecallback接口的onmapdrawframe(mapstatus drawingmapstatus)方法来进行绘制，在地图渲染每一帧的过程中，以及每次需要重绘地图时（如添加覆盖物），该接口都会被调用。
自v4.2.0起，旧版的onmapdrawframe(gl10 gl, mapstatus drawingmapstatus)方法废弃。

下面代码以在地图上绘制3d立方体为例，介绍如何使用opengl绘制接口。

privateclasscubeshader{
    int mvertex;
    int mmvpmatrix;
    int mcolor;
    int mprogram;
publiccubeshader(){
}
string vertexshader ="precision highp float;\n"
"        attribute vec3 mvertex;//顶点数组,三维坐标\n"
"        attribute vec4 mcolor;//颜色数组,三维坐标\n"
"        uniform mat4 mmvpmatrix;//mvp矩阵\n"
"        varying vec4 color;//\n"
"        void main(){\n"
"            gl_position = mmvpmatrix * vec4(mvertex, 1.0);\n"
"            color = mcolor;\n"
"        }";
string fragmentshader ="//有颜色 没有纹理\n"
"        precision highp float;\n"
"        varying vec4 color;//\n"
"        void main(){\n"
"            gl_fragcolor = color;\n"
"        }";
publicvoidinit(){
        int vertexlocation =gles20.glcreateshader(gles20.gl_vertex_shader);
gles20.glshadersource(vertexlocation, vertexshader);
gles20.glcompileshader(vertexlocation);
        int fragmentlocation =gles20.glcreateshader(gles20.gl_fragment_shader);
gles20.glshadersource(fragmentlocation, fragmentshader);
gles20.glcompileshader(fragmentlocation);
        mprogram =gles20.glcreateprogram();
gles20.glattachshader(mprogram, vertexlocation);
gles20.glattachshader(mprogram, fragmentlocation);
gles20.gllinkprogram(mprogram);
        mvertex  =gles20.glgetattriblocation(mprogram,"mvertex");
        mmvpmatrix =gles20.glgetuniformlocation(mprogram,"mmvpmatrix");
        mcolor =gles20.glgetattriblocation(mprogram,"mcolor");
}
}

1、声明所需数据及属性

// 3d立方体顶点绘制顺序列表
private short[] mdrawindices ={
0,4,5,0,5,1,1,5,6,1,6,2,2,6,7,2,7,3,3,7,4,3,4,0,4,7,6,4,6,5,3,0,1,3,1,2
};
// 3d立方体8个顶点颜色值
private float[] mvertexcolors ={
        1f, 1f, 0f, 1f,
        0f, 1f, 1f, 1f,
        1f, 0f, 1f, 1f,
        0f, 0f, 0f, 1f,
        1f, 1f, 1f, 1f,
        1f, 0f, 0f, 1f,
        0f, 1f, 0f, 1f,
        0f, 0f, 1f, 1f
};
// 立方体顶点坐标buffer
privatefloatbuffer mvertextbuffer;
// 顶点绘制顺序buffer
privateshortbuffer mindexbuffer;
// 立方体顶点颜色buffer
privatefloatbuffer mcolorbuffer;
// 3d立方体着色器
privatecubeshader mcubeshader;

2、初始化数据

privatevoidinitcubemodeldata(float width, float height, float depth){
// 对标墨卡托坐标
    width = width *10000/2;
    height = height *10000/2;
    depth = depth *10000/2;
// 立方体8个顶点坐标
    float[] vertices ={
-width,-height,-0,
            width,-height,-0,
            width, height,-0,
-width, height,-0,
-width,-height, depth,
            width,-height, depth,
            width, height, depth,
-width, height, depth,
};
    mvertextbuffer =bytebuffer.allocatedirect(vertices.length*4)
.order(byteorder.nativeorder())
.asfloatbuffer();
    mvertextbuffer.put(vertices).position(0);
// 立方体顶点绘制顺序buffer
bytebuffer bytebuffer =bytebuffer.allocatedirect(mdrawindices.length*4);
    bytebuffer.order(byteorder.nativeorder());
    mindexbuffer = bytebuffer.asshortbuffer();
    mindexbuffer.put(mdrawindices);
    mindexbuffer.position(0);
// 立方体顶点颜色buffer
bytebuffer bytebuffer1 =bytebuffer.allocatedirect(mvertexcolors.length*4);
    bytebuffer1.order(byteorder.nativeorder());
    mcolorbuffer = bytebuffer1.asfloatbuffer();
    mcolorbuffer.put(mvertexcolors);
    mcolorbuffer.position(0);
}

1、创建onmapdrawframecallback实例

baidumap.onmapdrawframecallback callback =newbaidumap.onmapdrawframecallback(){
//废弃
    @override
publicvoidonmapdrawframe(gl10 gl,mapstatus drawingmapstatus){
}
    @override
publicvoidonmapdrawframe(mapstatus drawingmapstatus){
if(null== mbaidumap.getprojection()){
return;
}
drawframefor3dcube(drawingmapstatus,0.2f,0.2f,0.3f);
}
};

2、设置onmapdrawframecallback接口

mbaidumap.setonmapdrawframecallback(callback);

3、绘制方法

/**
 * 绘制3d立方体
 * @param drawingmapstatus
 */
privatevoiddrawcube(mapstatus drawingmapstatus){
if(null== mcubeshader ||null== drawingmapstatus){
return;
}
// step1 初始化数据
    float[] mvpmatrix =newfloat[16];
matrix.setidentitym(mvpmatrix,0);
// 获取投影矩阵
    float[] projectmatrix = mbaidumap.getprojectionmatrix();
// 获取视图矩阵
    float[] viewmatrix = mbaidumap.getviewmatrix();
matrix.multiplymm(mvpmatrix,0, projectmatrix,0, viewmatrix,0);
// 绑定地图移动
pointf p1f = mbaidumap.getprojection().toopengllocation(latlng1, drawingmapstatus);
matrix.translatem(mvpmatrix,0, p1f.x, p1f.y,0);
// 设置缩放比例
    int scale =1;
matrix.scalem(mvpmatrix,0, scale, scale, scale);
// step2 开始绘制设置
gles20.gluseprogram(mcubeshader.mprogram);
gles20.glenable(gles20.gl_depth_test);
// 顶点指针
gles20.glenablevertexattribarray(mcubeshader.mvertex);
gles20.glvertexattribpointer(mcubeshader.mvertex,3,gles20.gl_float,false,0, mvertextbuffer);
// 颜色指针
gles20.glenablevertexattribarray(mcubeshader.mcolor);
gles20.glvertexattribpointer(mcubeshader.mcolor,4,gles20.gl_float,false,0, mcolorbuffer);
gles20.gluniformmatrix4fv(mcubeshader.mmvpmatrix,1,false, mvpmatrix,0);
// 开始画
gles20.gldrawelements(gles20.gl_triangles, mdrawindices.length,gles20.gl_unsigned_short, mindexbuffer);
gles20.gldisablevertexattribarray(mcubeshader.mvertex);
gles20.gldisable(gles20.gl_depth_test);
}

效果如图：