用BabylonJS获得黑色截图

Question

我很难拍截图。如果您跟随tut，at：png，您会看到它们只提供了一行BABYLON.Tools.CreateScreenshot(engine, camera, size);

尺寸和相机是你可以改变的变量。当我实现这一点时，我会得到一个黑色的截图。我最初认为，它可能是在页面呈现之前获取一个屏幕快照，所以我添加了一个简单的循环，并添加了一个警告框，以等待在屏幕截图执行之前加载的场景。但出于某种原因我还是得到了一个黑色的截图。谢谢你的意见:D

var canvas = document.querySelector("#renderCanvas");
var engine = new BABYLON.Engine(canvas, true);

//Needed for the CreateScene Function
var createScene = function () {
var scene = new BABYLON.Scene(engine);

// Setup camera
var camera = new BABYLON.ArcRotateCamera("Camera", 0, 10, 0, BABYLON.Vector3.Zero(), scene);
camera.setPosition(new BABYLON.Vector3(-10, 10, 25));
camera.attachControl(canvas, true);

// Lights
var light0 = new BABYLON.PointLight("Omni0", new BABYLON.Vector3(0, 10, 5), scene);
var light1 = new BABYLON.PointLight("Omni1", new BABYLON.Vector3(0, -10, 5), scene);
var light2 = new BABYLON.PointLight("Omni2", new BABYLON.Vector3(10, 0, 5), scene);
var light3 = new BABYLON.DirectionalLight("Dir0", new BABYLON.Vector3(1, -1, 2), scene);
var light4 = new BABYLON.SpotLight("Spot0", new BABYLON.Vector3(0, 5, -10), new BABYLON.Vector3(0, -1, 0), 0.8, 3, scene);
var light5 = new BABYLON.HemisphericLight("Hemi0", new BABYLON.Vector3(0, 1, 0), scene);

var material = new BABYLON.StandardMaterial("kosh", scene);
var sphere = BABYLON.Mesh.CreateSphere("Sphere", 16, 3, scene);
var cylinder = BABYLON.Mesh.CreateCylinder("cylinder", 7.5, 3, 6, 6, 1, scene);
var box = BABYLON.Mesh.CreateBox("box", 6.0, scene);

// Creating light sphere
var lightSphere0 = BABYLON.Mesh.CreateSphere("Sphere0", 16, .5, scene);
var lightSphere1 = BABYLON.Mesh.CreateSphere("Sphere1", 16, 0.5, scene);
var lightSphere2 = BABYLON.Mesh.CreateSphere("Sphere2", 16, 0.5, scene);

//Shifting position up of Sphere
sphere.position.y = 5;
box.position.y = -2;

//generating shadows
var shadowGenerator = new BABYLON.ShadowGenerator(1024, light3);
shadowGenerator.getShadowMap().renderList.push(box);
shadowGenerator.getShadowMap().renderList.push(sphere);
shadowGenerator.getShadowMap().renderList.push(cylinder);

//Colors
lightSphere0.material = new BABYLON.StandardMaterial("red", scene);
lightSphere0.material.diffuseColor = new BABYLON.Color3(0, 0, 0);
lightSphere0.material.specularColor = new BABYLON.Color3(0, 0, 0);
lightSphere0.material.emissiveColor = new BABYLON.Color3(1, 0, 0);

lightSphere1.material = new BABYLON.StandardMaterial("green", scene);
lightSphere1.material.diffuseColor = new BABYLON.Color3(0, 0, 0);
lightSphere1.material.specularColor = new BABYLON.Color3(0, 0, 0);
lightSphere1.material.emissiveColor = new BABYLON.Color3(0, 1, 0);

lightSphere2.material = new BABYLON.StandardMaterial("blue", scene);
lightSphere2.material.diffuseColor = new BABYLON.Color3(0, 0, 0);
lightSphere2.material.specularColor = new BABYLON.Color3(0, 0, 0);
lightSphere2.material.emissiveColor = new BABYLON.Color3(0, 0, 1);

// Sphere material
material.diffuseColor = new BABYLON.Color3(1, 1, 1);
sphere.material = material;

// Lights colors
light0.diffuse = new BABYLON.Color3(1, 0, 0);
light0.specular = new BABYLON.Color3(1, 0, 0);

light1.diffuse = new BABYLON.Color3(0, 1, 0);
light1.specular = new BABYLON.Color3(0, 1, 0);

light2.diffuse = new BABYLON.Color3(0, 0, 1);
light2.specular = new BABYLON.Color3(0, 0, 1);

light3.diffuse = new BABYLON.Color3(1, 1, 1);
light3.specular = new BABYLON.Color3(1, 1, 1);

light4.diffuse = new BABYLON.Color3(1, 0, 0);
light4.specular = new BABYLON.Color3(1, 1, 1);

light5.diffuse = new BABYLON.Color3(1, 1, 1);
light5.specular = new BABYLON.Color3(1, 1, 1);
light5.groundColor = new BABYLON.Color3(0, 0, 0);

//Adding the SkyBox
var skybox = BABYLON.Mesh.CreateBox("skyBox", 100.0, scene);
var skyboxMaterial = new BABYLON.StandardMaterial("skyBox", scene);
skyboxMaterial.backFaceCulling = false;
skyboxMaterial.reflectionTexture = new BABYLON.CubeTexture("../textures/TropicalSunnyDay", scene);
skyboxMaterial.reflectionTexture.coordinatesMode = BABYLON.Texture.SKYBOX_MODE;
skyboxMaterial.diffuseColor = new BABYLON.Color3(0, 0, 0);
skyboxMaterial.specularColor = new BABYLON.Color3(0, 0, 0);
skyboxMaterial.disableLighting = true;
skybox.material = skyboxMaterial;

// Animations
var alpha = 0;
scene.beforeRender = function () {
    light0.position = new BABYLON.Vector3(10 * Math.sin(alpha), 0, 10 * Math.cos(alpha));
    light1.position = new BABYLON.Vector3(10 * Math.sin(alpha), 0, -10 * Math.cos(alpha));
    light2.position = new BABYLON.Vector3(10 * Math.cos(alpha), 0, 10 * Math.sin(alpha));

    lightSphere0.position = light0.position;
    lightSphere1.position = light1.position;
    lightSphere2.position = light2.position;

    lightSphere0.position.y = 5;
    lightSphere1.position.y = 5;
    lightSphere2.position.y = 5;

    alpha += 0.01;
};

//ground
var ground = BABYLON.Mesh.CreateGround("ground1", 100, 100, 2, scene);
ground.receiveShadows = true;

var materialGround = new BABYLON.StandardMaterial("grassTexture", scene);
materialGround.diffuseColor = new BABYLON.Color3(1,1,1);
materialGround.diffuseTexture = new 
BABYLON.Texture("../textures/grass.png",scene);
ground.material = materialGround;



//wait loop for the screenshot
size = { width: 600, height: 400};
var i = 1;
function myLoop () {
    setTimeout(function () {
        alert('Taking Screenshot!');
        //Creating png screenshot
        BABYLON.Tools.CreateScreenshot(engine, camera, size);
        i++;
        if (i < 1) {
            myLoop();
        }
    }, 2000)
}

myLoop();

//Returning the scene
return scene;
};

var scene = createScene();
engine.runRenderLoop(function () {
    scene.render();
});
window.addEventListener("resize", function () {
    engine.resize();
});

Answer 1

DeltaKosh在htmlgameDevs帮了我的忙。他说，当您为屏幕快照或呈现PNG文件创建引擎时，您必须这样定义它：

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

我还添加了一个循环，等待一秒钟，直到场景呈现后才拍摄截图。

 var scene = createScene();
 var booleanR = false;
 var size = 512;
 engine.runRenderLoop(function () {
    scene.render();
 });

 function myLoop () {
     setTimeout(function () {
        if(booleanR == false){
             BABYLON.Tools.CreateScreenshot(engine, camera, size);
             booleanR = true;
      }
   }, 1000)
}

这是他回复的链接：http://www.html5gamedevs.com/topic/32765-getting-a-black-screenshot-with-babylonjs/?tab=comments#comment-187819