Question

每个人，

我正在尝试为映射到平面上的基于Canvas的纹理设置动画，就像广告牌一样。我已经提到了包括 material.needsUpdate ＆amp; texture.needsUpdate ，但我仍然无法让纹理变得生动。我还包括一个旋转的立方体，所以我知道动画例程在某种程度上起作用。

以下是代码：


    
      
      
        if ( window.innerWidth === 0 ) { window.innerWidth = parent.innerWidth; window.innerHeight = parent.innerHeight; }

            var camera, scene, renderer;
            var mesh, geometry, material;
            var light, sign, animTex;
            var canvas, context;

            init();
            animate();

            function init() {

                camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 1200 );
                camera.position.z = 700;

                scene = new THREE.Scene();

                material = new THREE.MeshLambertMaterial(
                    { color: 0x885522
                    , wireframe: false
                     , overdraw: false
                    } );
                geometry = new THREE.CubeGeometry( 80, 120, 100, 1,1,1);
                mesh = new THREE.Mesh( geometry, material );

                sign = createSign();

                light = new THREE.DirectionalLight(0xFFFFFF, 3.0);
                light.position = new THREE.Vector3(5,10,7);
                light.target = new THREE.Vector3(0,0,0);

                scene.add( mesh );
                scene.add( sign );
                scene.add( light );

                renderer = new THREE.CanvasRenderer();
                renderer.setSize( window.innerWidth, window.innerHeight );
                document.body.appendChild( renderer.domElement );

            }
            function createSign() {
                canvas = document.createElement("canvas");
                context = canvas.getContext("2d");
                canvas.width = 200;
                canvas.height = 200;
                context = canvas.getContext("2d");              
                var texture = new THREE.Texture(canvas);
                texture.needsUpdate = true;
                var material = new THREE.MeshBasicMaterial({ map : texture, overdraw: true });
                material.needsUpdate = true;
                var mesh = new THREE.Mesh(new THREE.PlaneGeometry(200, 200), material);
                mesh.doubleSided = true;
                return mesh;
            }

            function animate() {

                var time = Date.now()*0.01;
                var sinTime = Math.sin ( time * 0.05 ) * 100;
                var cosTime = Math.cos ( time * 0.05 ) * 100;

                mesh.rotation.y = sinTime*0.01;

                requestAnimationFrame( animate );
                context.fillStyle="black";
                context.fillRect(0,0,canvas.width,canvas.height);
                context.fillStyle="white";
                context.fillRect ( (canvas.width/2) + sinTime, (canvas.height/2) + cosTime, 20, 20 )
                renderer.render( scene, camera );
            }

这会运行，但我似乎无法更新Canvas纹理材质。我忽略了什么？非常感谢任何指针！

Answer 1

在render()电话前放置此权利：

sign.material.map.needsUpdate = true;

小提琴：http://jsfiddle.net/pPKVa/

Answer 2

每次使用纹理时（每个渲染循环）needsUpdate标志都会重置（为假），因此需要在渲染循环中设置为true（在渲染调用之前，或者它为＆＃39） ;将是一个框架关闭）。因此，在您的示例中，将sign.material.map.needsUpdate = true放在renderer.render( scene, camera )之前。 texture.needsUpdate = true不需要。

此外，您只需在纹理上设置material.needsUpdate = true标记，因为材质属性不会发生变化。

在THREE.js动画画布广告牌

2 个答案: