三维地图实现下雨效果源代码
三维地图服务器 下载地址：http://download.bigemap.com/bm3Dserver.rar （最新版）
安装以上SDK后，启动，启动面板上找到开发使用，如下图源代码：
//注释：安装地图服务器后，下列代码中的 http://bigemap.com 替换成 http://localhost ，其他不变
<!DOCTYPE html>
<html>
<head>
<meta charset='UTF-8'/>
<meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no'/>
<link href='http://bigemap.com:9000/bigemap-gl.js/v1.1.0/Widgets/widgets.css' rel='stylesheet'/>
<script src='http://bigemap.com:9000/bigemap-gl.js/v1.1.0/bigemap-gl.js'></script>
<style>
body {
margin: 0;
padding: 0;
}
#container {
position: absolute;
top: 0;
bottom: 0;
width: 100%;
}
.bmgl-widget-credits{display:none}
</style>
<title>part_test</title>
</head>
<body>
<div id='container'></div>
<script>
bmgl.Config.HTTP_URL = 'http://bigemap.com:9000';
var viewer = new bmgl.Viewer('container', {mapId:'bigemap.googlemap-satellite',requestRenderMode:false});
viewer.camera.setView({
destination: bmgl.Cartesian3.fromDegrees(104, 30, 300000)
});
//定义下雨场景 着色器\\return fract(sin(x*133.3)*13.13);
function FS_Rain() {
return "uniform sampler2D colorTexture;\n\
varying vec2 v_textureCoordinates;\n\
\n\
float hash(float x){\n\
return fract(sin(x*23.3)*13.13);\n\
}\n\
\n\
void main(void){\n\
\n\
float time = czm_frameNumber / 60.0;\n\
vec2 resolution = czm_viewport.zw;\n\
\n\
vec2 uv=(gl_FragCoord.xy*2.-resolution.xy)/min(resolution.x,resolution.y);\n\
vec3 c=vec3(.6,.7,.8);\n\
\n\
float a=-.4;\n\
float si=sin(a),co=cos(a);\n\
uv*=mat2(co,-si,si,co);\n\
uv*=length(uv+vec2(0,4.9))*.3+1.;\n\
\n\
float v=1.-sin(hash(floor(uv.x*100.))*2.);\n\
float b=clamp(abs(sin(20.*time*v+uv.y*(5./(2.+v))))-.95,0.,1.)*20.;\n\
c*=v*b; \n\
\n\
gl_FragColor = mix(texture2D(colorTexture, v_textureCoordinates), vec4(c,1), 0.5); \n\
}\n\
";
}
var collection = viewer.scene.postProcessStages;
var fs_rain = FS_Rain();
var snow = new bmgl.PostProcessStage({
name: 'czm_rain',
fragmentShader: fs_rain
});
collection.add(snow);
</script>
</body>
</html>
效果图;