BabylonJS - 创建屏幕截图

要捕获当前正在工作的屏幕，无法使用打印屏幕按键以高分辨率截取屏幕截图。BabylonJS 提供了 createscreenshot API，可帮助您实现此目的。它将文件保存为 png 格式，并且不会牺牲图像质量。

语法

要截取屏幕截图，我们需要提供引擎、相机和尺寸，如下所示。

BABYLON.Tools.CreateScreenshot(engine, camera, { width: 1024, height: 300 }, function (data) {
    var img = document.createElement("img");
    img.src = data;
    document.body.appendChild(img);
});

添加一个按钮，当用户点击该按钮时，会调用屏幕截图 API。

对传递给屏幕截图 API 的引擎进行了更改。

var engine = new BABYLON.Engine(canvas, true, {
preserveDrawingBuffer: true, stencil: true
});

需要将 preserveDrawingBuffer 和 stencil 等选项设置为 true。

按钮添加方式如下 −

ssButton = document.createElement("input");
document.body.appendChild (ssButton);

为上面的按钮添加单击事件，并调用 createscreenshot。它将在屏幕末尾更新屏幕截图。用于图像 src 的数据已创建屏幕截图 url。

演示

<!doctype html>
<html>
   <head>
      <meta charset = "utf-8">
      <title>BabylonJs - Basic Element-Creating Scene</title>
      <script src = "babylon.js"></script>
      <style>
         canvas {width: 100%; height: 100%;}
      </style>
   </head>

   <body>
      <canvas id = "renderCanvas"></canvas>
      <script type = "text/javascript">
         var canvas = document.getElementById("renderCanvas");
         var engine = new BABYLON.Engine(canvas, true, { preserveDrawingBuffer: true, stencil: true });	
         var createScene  = function() {
            var scene = new BABYLON.Scene(engine);
            
            // Setup environment
            var light = new BABYLON.HemisphericLight("light1", new BABYLON.Vector3(1, 0.5, 0), scene);
            
            var camera = new BABYLON.ArcRotateCamera("ArcRotateCamera", 1, 0.8, 20, new BABYLON.Vector3(0, 0, 0), scene);
            camera.attachControl(canvas, true);

            var gmat = new BABYLON.StandardMaterial("mat1", scene);
            gmat.alpha = 1.0;
            
            //gmat.diffuseColor = new BABYLON.Color3(1, 0, 0);
            var texture = new BABYLON.Texture("images/mat.jpg", scene);
            gmat.diffuseTexture = texture;

            var ground = BABYLON.MeshBuilder.CreateGround("ground", {width: 150, height:15}, scene);
            ground.material = gmat;

            var mat = new BABYLON.StandardMaterial("mat1", scene);
            mat.alpha = 1.0;
            mat.diffuseColor = new BABYLON.Color3(1, 0, 0);
            
            var texture = new BABYLON.Texture("images/rugby.jpg", scene);
            mat.diffuseTexture = texture;

            var sphere = BABYLON.MeshBuilder.CreateSphere("sphere", {diameter: 2, diameterX: 3}, scene);
            sphere.position= new BABYLON.Vector3(15,1,0);
            sphere.material = mat;

            var faceColors = new Array();
            faceColors[1] = new BABYLON.Color4(0,1,0,1);   // green front

            var matcone = new BABYLON.StandardMaterial("mat1", scene);
            matcone.alpha = 1.0;
            matcone.diffuseColor = new BABYLON.Color3(0.9, 0, 2);
            
            var texture = new BABYLON.Texture("images/cone.jpg", scene);
            matcone.diffuseTexture = texture;

            var cone = BABYLON.MeshBuilder.CreateCylinder("cone", {diameterTop: 0, tessellation: 4}, scene);
            cone.position= new BABYLON.Vector3(12,1,0);
            cone.material = matcone;

            var matplane = new BABYLON.StandardMaterial("matplane", scene);
            matplane.alpha = 1.0;
            matplane.diffuseColor = new BABYLON.Color3(0.9, 0, 2);
            
            var texture = new BABYLON.Texture("images/board.jpg", scene);
            matplane.diffuseTexture = texture;
            var plane = BABYLON.MeshBuilder.CreatePlane("plane", {width: 5, height : 5}, scene);
            plane.position= new BABYLON.Vector3(9,2.5,0);
            plane.material = matplane;		
            
            var disc = BABYLON.MeshBuilder.CreateDisc("disc", {tessellation: 3}, scene);
            disc.position= new BABYLON.Vector3(5,1,0);		

            var mattorus = new BABYLON.StandardMaterial("matoct", scene);
            mattorus.alpha = 1.0;
            
            var texture = new BABYLON.Texture("images/ring.jpg", scene);
            mattorus.diffuseTexture = texture;
            
            var torus = BABYLON.MeshBuilder.CreateTorus("torus", {thickness: 0.5}, scene);		
            torus.position= new BABYLON.Vector3(3,1,0);
            torus.material = mattorus;

            var matoct = new BABYLON.StandardMaterial("matoct", scene);
            matoct.alpha = 1.0;
            
            var texture = new BABYLON.Texture("images/d1.png", scene);
            matoct.diffuseTexture = texture;
            var octahedron = BABYLON.MeshBuilder.CreatePolyhedron("oct", {type: 1, size: 3}, scene);
            
            octahedron.position= new BABYLON.Vector3(-2,5,0);
            octahedron.material = matoct;	

            var matico = new BABYLON.StandardMaterial("matico", scene);
            matico.alpha = 1.0;
            
            var texture = new BABYLON.Texture("images/diamond.jpg", scene);
            matico.diffuseTexture = texture;		
            
            var icosphere = BABYLON.MeshBuilder.CreateIcoSphere("ico", {radius: 5, radiusY: 3, subdivisions: 2}, scene);
            icosphere.position= new BABYLON.Vector3(-13,3,0);		
            icosphere.material = matico;		
            
            //add screenshot button
            var ssButton = document.getElementById("takescreenshot");
            if (ssButton == null) {
               ssButton = document.createElement("input");
               document.body.appendChild(ssButton);
            }
            
            ssButton.id = "takescreenshot";
            ssButton.type = "button";
            ssButton.style.position = "fixed";
            ssButton.style.right = "0px";
            ssButton.style.top = "100px";
            ssButton.value = "create screenshot";
            
            ssButton.onclick = function () {
               BABYLON.Tools.CreateScreenshot(engine, camera, { width: 1024, height: 300 },
               function (data) {
                  var img = document.createElement("img");
                  img.src = data;
                  document.body.appendChild(img);
               });
            };			
            return scene;
         }
         var scene = createScene();
         engine.runRenderLoop(function() {
            scene.render();
         });	
      </script>
   </body>
</html>