Search code examples
three.jslight

Three.js: How to add and remove lights at run time?


I am trying hard for couple days, what is wrong in my code? Three.js does not update lights. I help will be apprecitared which may solve my problem.

I tried a lot of combinations of the following code but I din not get any success.

function LightFunc(Light){

      scene.remove(spotLight1);
      scene.remove(spotLight2);
      cubeMaterial.needsUpdate=true;
      planeMaterial.needsUpdate=true;

      if (document.getElementById('Light1').checked) {
        spotLight1 = new THREE.SpotLight(0xffffff);
        spotLight1.position.set(15,30,50);
        spotLight1.castShadow = true;
        scene.add(spotLight1);
      }
      if (document.getElementById('Light2').checked) {
        spotLight2 = new THREE.SpotLight(0xffffff);
        spotLight2.position.set(15,30,-50);
        spotLight2.castShadow = true;
        scene.add(spotLight2);
      }
      }

    // step1: how to create scene
    var scene = new THREE.Scene();

    // step2: how to create camera
    var camera = new THREE.PerspectiveCamera(45, 4/3, .1, 500)
    camera.position.set(40,40,40);
    camera.lookAt(scene.position);

    // step3: how to create renderer
    var renderer = new THREE.WebGLRenderer();
    renderer.setClearColor(0xdddddd);
    renderer.setSize(800, 600);
    renderer.shadowMap.enabled = true;
    renderer.shadowMap.type = THREE.PCFSoftShadowMap;

    // step4: how to create axis
    var axis = new THREE.AxesHelper(10);
    scene.add(axis);

    // step5: how to create color
    var color = new THREE.Color("rgb(255, 0, 0)");

    // step6: how to create grid
    var grid = new THREE.GridHelper(50,5,color,0x000000);
    scene.add(grid);

    // step7: how to create cube
    var cubeGeo = new THREE.BoxGeometry(5,5,5);
    var cubeMaterial = new THREE.MeshLambertMaterial({color:0xff3300});
    var cube = new THREE.Mesh(cubeGeo,cubeMaterial);
    cube.position.set(2.5,2.5,2.5);
    cube.castShadow = true;
    cube.receiveShadow = false;
    scene.add(cube);

    // step8: how to create plane
    var planeGeo = new THREE.PlaneGeometry(30,30,30);
    var planeMaterial = new THREE.MeshLambertMaterial({color:0x00ff00});
    var plane = new THREE.Mesh(planeGeo,planeMaterial);
    plane.rotation.x = -.5*Math.PI;
    plane.receiveShadow = true;
    scene.add(plane);

    // step9: how to create spot lights

    var spotLight1 = new THREE.SpotLight(0xffffff);
    spotLight1.position.set(15,30,50);
    spotLight1.castShadow = true;
    scene.add(spotLight1);

    var spotLight2 = new THREE.SpotLight(0xffffff);
    spotLight2.position.set(15,30,-50);
    spotLight2.castShadow = true;
    scene.add(spotLight2);

    var canvas = document.getElementById("canvas");
    canvas.appendChild(renderer.domElement);
    renderer.render(scene,camera);
<html>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r123/three.min.js"></script>
    <body>
      <div id="canvas" width="800px" height="600px"></div>
      <div>
        <input type="checkbox" id="Light1" name="Light1" value="Light1" onchange="LightFunc();" checked >
        <label for="Light1"> Light1</label><br>
        <input type="checkbox" id="Light2" name="Light2" value="Light2" onchange="LightFunc();" checked >
        <label for="Light2"> Light2</label><br>
      </div>
    </body> 
</html>

I am trying hard for couple days, what is wrong in my code? Three.js does not update lights. I help will be apprecitared which may solve my problem.

I tried a lot of combinations of the following code but I din not get any success.


Solution

  • Since you are not having an animation loop in your scene, you have to render it again when changing the light settings.

    function LightFunc(Light){
    
          scene.remove(spotLight1);
          scene.remove(spotLight2);
          cubeMaterial.needsUpdate=true;
          planeMaterial.needsUpdate=true;
    
          if (document.getElementById('Light1').checked) {
            spotLight1 = new THREE.SpotLight(0xffffff);
            spotLight1.position.set(15,30,50);
            spotLight1.castShadow = true;
            scene.add(spotLight1);
          }
          if (document.getElementById('Light2').checked) {
            spotLight2 = new THREE.SpotLight(0xffffff);
            spotLight2.position.set(15,30,-50);
            spotLight2.castShadow = true;
            scene.add(spotLight2);
          }
          renderer.render(scene,camera); // FIX
          }
    
        // step1: how to create scene
        var scene = new THREE.Scene();
    
        // step2: how to create camera
        var camera = new THREE.PerspectiveCamera(45, 4/3, .1, 500)
        camera.position.set(40,40,40);
        camera.lookAt(scene.position);
    
        // step3: how to create renderer
        var renderer = new THREE.WebGLRenderer();
        renderer.setClearColor(0xdddddd);
        renderer.setSize(800, 600);
        renderer.shadowMap.enabled = true;
        renderer.shadowMap.type = THREE.PCFSoftShadowMap;
    
        // step4: how to create axis
        var axis = new THREE.AxesHelper(10);
        scene.add(axis);
    
        // step5: how to create color
        var color = new THREE.Color("rgb(255, 0, 0)");
    
        // step6: how to create grid
        var grid = new THREE.GridHelper(50,5,color,0x000000);
        scene.add(grid);
    
        // step7: how to create cube
        var cubeGeo = new THREE.BoxGeometry(5,5,5);
        var cubeMaterial = new THREE.MeshLambertMaterial({color:0xff3300});
        var cube = new THREE.Mesh(cubeGeo,cubeMaterial);
        cube.position.set(2.5,2.5,2.5);
        cube.castShadow = true;
        cube.receiveShadow = false;
        scene.add(cube);
    
        // step8: how to create plane
        var planeGeo = new THREE.PlaneGeometry(30,30,30);
        var planeMaterial = new THREE.MeshLambertMaterial({color:0x00ff00});
        var plane = new THREE.Mesh(planeGeo,planeMaterial);
        plane.rotation.x = -.5*Math.PI;
        plane.receiveShadow = true;
        scene.add(plane);
    
        // step9: how to create spot lights
    
        var spotLight1 = new THREE.SpotLight(0xffffff);
        spotLight1.position.set(15,30,50);
        spotLight1.castShadow = true;
        scene.add(spotLight1);
    
        var spotLight2 = new THREE.SpotLight(0xffffff);
        spotLight2.position.set(15,30,-50);
        spotLight2.castShadow = true;
        scene.add(spotLight2);
    
        var canvas = document.getElementById("canvas");
        canvas.appendChild(renderer.domElement);
        renderer.render(scene,camera);
    <html>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r123/three.min.js"></script>
        <body>
          <div id="canvas" width="800px" height="600px"></div>
          <div>
            <input type="checkbox" id="Light1" name="Light1" value="Light1" onchange="LightFunc();" checked >
            <label for="Light1"> Light1</label><br>
            <input type="checkbox" id="Light2" name="Light2" value="Light2" onchange="LightFunc();" checked >
            <label for="Light2"> Light2</label><br>
          </div>
        </body> 
    </html>