WebGL自學課程(10):通過OpenStreetMap獲取資料繪製地球
阿新 • • 發佈:2019-01-26
好久沒寫部落格了,今天再寫一篇。前幾天想通過OpenStreetMap訪問資料來繪製一個最最最最最簡單的WebGoogleEarth的雛形,這個Demo比較簡單,只是簡單的獲取OpenStreetMap某一個切片層級下面的所有的切片,然後按照正確的貼圖方式繪製在地球上,也就是說這個Demo沒有考慮圖層的動態管理等等。最後將渲染的程式碼以EarthOSM類的形式封裝到了自己的World.js中,可以用滑鼠進行三維互動,World.js的連結地址是http://blog.csdn.net/sunqunsunqun/article/details/7885639.
下面是截圖:
下面是放大後的截圖:
以下是前端程式碼:
<!DOCTYPE HTML> <html> <head> <title>WebGL Terrain Map</title> <meta http-equiv="Content-Type" content="text/html"/> <meta name="charset" content="utf-8"/> <style type="text/css"> html, body { margin: 0; padding: 0; width: 100%; height: 100% ;font-family:"Times New Roman",Georgia,Serif;} div { margin: 0; padding: 0 } .head{width:100%; height:25px; background-color:#5998DD;color:#ffffff;font-size:13px; line-height:25px;border-top-left-radius:5px;border-top-right-radius:5px;-webkit-border-top-left-radius:5px; -webkit-border-top-right-radius:5px;-moz-border-radius-topleft:5px;-moz-border-radius-topright:5px;} .tip{font-size:8px;display:block;height:8px;margin-left:3px;margin-top:9px;} </style> <script src='http://serverapi.arcgisonline.com/jsapi/arcgis/?v=3.1' data-dojo-config='parseOnLoad: true'> <script type="text/javascript" src="World0.3.4.js"></script> <script type="text/javascript" src="CanvasEventHandler.js"></script> <script type="text/javascript"> var vertexShaderContent,fragmentShaderContent,camera,scene,renderer,earthOSM; function getShaderContent(shaderType){ var shaderUrl; if(shaderType == "VERTEX_SHADER"){ shaderUrl = "VertexShader.txt"; } else if(shaderType == "FRAGMENT_SHADER"){ shaderUrl = "FragmentShader.txt"; } var xhrArgs = { url:shaderUrl, handleAs:"text", sync:true, preventCache:true, load:function(data){ if(shaderType == "VERTEX_SHADER"){ vertexShaderContent = data; } else if(shaderType == "FRAGMENT_SHADER"){ fragmentShaderContent = data; } }, error:function(error){ alert("獲取ShaderContent出錯!"); } }; dojo.xhrGet(xhrArgs); } function startWebGL(){ getShaderContent("VERTEX_SHADER"); getShaderContent("FRAGMENT_SHADER"); renderer = new World.WebGLRenderer(dojo.byId("canvasId"),vertexShaderContent,fragmentShaderContent); //World.enableAmbientLight(); //World.enableParallelLlight(new World.Vector(0,-30,-50),new World.Vertice(0,0,0.8)); World.disableAmbientLight(); World.disableParallelLlight(); camera = new World.PerspectiveCamera(90,1,1.0,200.0); camera.look(new World.Vertice(0,0,60),new World.Vertice(0,0,0)); scene = new World.Scene(); earthOSM = new World.EarthOSM(40,5); scene.add(earthOSM); renderer.bindScene(scene); renderer.bindCamera(camera); renderer.setIfAutoRefresh(true); } function initEvents(){ dojo.connect(dojo.byId("canvasId"),"mousedown",onMouseDown); dojo.connect(dojo.byId("canvasId"),"onmouseup",onMouseUp); dojo.connect(dojo.byId("canvasId"),'mousewheel',onMouseWheel); dojo.connect(dojo.byId("canvasId"),'DOMMouseScroll',onMouseWheel); } function initAll(){ initEvents(); startWebGL(); } dojo.addOnLoad(initAll); </script> </head> <body> <canvas id="canvasId" width="625" height="625"></canvas> </body> </html>
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