在HTML中更改three.js背景为透明或其他颜色

在HTML中更改three.js背景为透明或其他颜色

参考: Changing three.js background to transparent or another color in HTML

Three.js 是一个基于WebGL的JavaScript库,它使得在网页上创建和显示3D图形变得简单。在使用three.js时,我们可能需要根据不同的设计需求改变场景的背景颜色,或者将其设置为透明。本文将详细介绍如何在HTML中使用three.js更改背景颜色或设置为透明,并提供多个示例代码以供参考。

1. 创建基本的three.js场景

在开始更改背景之前,我们首先需要创建一个基本的three.js场景。以下是一个创建场景、相机和渲染器的基本示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Three.js基本场景 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();
        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

2. 设置背景颜色

要设置three.js场景的背景颜色,可以直接设置scene.background属性。以下是一个设置背景颜色为蓝色的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>设置背景颜色 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();
        scene.background = new THREE.Color(0x0000ff); // 设置背景颜色为蓝色

        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

3. 设置背景为透明

如果我们想要将three.js场景的背景设置为透明,需要在创建WebGLRenderer时设置alpha选项为true,并将scene.background设置为null。以下是一个设置背景为透明的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>设置背景透明 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();
        scene.background = null; // 设置背景为透明

        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer({ alpha: true }); // 开启透明背景
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

4. 更改背景为渐变色

在three.js中,我们也可以通过使用THREE.Texture来创建一个渐变背景。以下是一个创建渐变背景的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>设置渐变背景 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();

        // 创建渐变纹理
        var canvas = document.createElement('canvas');
        canvas.width = 128;
        canvas.height = 128;
        var context = canvas.getContext('2d');
        var gradient = context.createLinearGradient(0, 0, 0, 128);
        gradient.addColorStop(0, '#ffffff'); // 白色
        gradient.addColorStop(1, '#0000ff'); // 蓝色
        context.fillStyle = gradient;
        context.fillRect(0, 0, canvas.width, canvas.height);

        var backgroundTexture = new THREE.CanvasTexture(canvas);
        scene.background = backgroundTexture;

        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

5. 使用CubeTextureLoader加载立方体纹理作为背景

我们还可以使用THREE.CubeTextureLoader来加载一组图像,作为场景的立方体纹理背景。以下是一个使用立方体纹理作为背景的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>立方体纹理背景 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();

        var loader = new THREE.CubeTextureLoader();
        var textureCube = loader.load([
            'px.jpg', 'nx.jpg',
            'py.jpg', 'ny.jpg',
            'pz.jpg', 'nz.jpg'
        ]);
        scene.background = textureCube;

        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

6. 动态更改背景颜色

我们可以通过编写JavaScript代码来动态更改three.js场景的背景颜色。以下是一个动态更改背景颜色的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>动态更改背景颜色 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();
        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 动态更改背景颜色
        var colorIndex = 0;
        var colors = [0xff0000, 0x00ff00, 0x0000ff]; // 红、绿、蓝

        function changeBackground() {
            scene.background = new THREE.Color(colors[colorIndex % colors.length]);
            colorIndex++;
            renderer.render(scene, camera);
        }

        setInterval(changeBackground, 1000); // 每秒更改一次背景颜色

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

7. 使用ShaderMaterial创建自定义背景

我们可以使用ShaderMaterial来创建自定义的背景效果。以下是一个使用ShaderMaterial创建背景的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>自定义Shader背景 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script>
        var scene = new THREE.Scene();
        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 创建自定义ShaderMaterial
        var customMaterial = new THREE.ShaderMaterial({
            uniforms: {},
            vertexShader: `
                void main() {
                    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
                }
            `,
            fragmentShader: `
                void main() {
                    gl_FragColor = vec4(0.5, 0.5, 0.5, 1.0); // 灰色背景
                }
            `
        });

        var planeGeometry = new THREE.PlaneGeometry(2, 2);
        var plane = new THREE.Mesh(planeGeometry, customMaterial);
        scene.add(plane);

        // 渲染场景和相机
        renderer.render(scene, camera);
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

8. 使用Post-processing改变背景

在three.js中,我们可以使用后处理(post-processing)效果来改变背景。以下是一个使用后处理改变背景的示例代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>后处理改变背景 - how2html.com</title>
    <style>
        body { margin: 0; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/postprocessing/EffectComposer.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/postprocessing/RenderPass.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/postprocessing/ShaderPass.js"></script>
    <script>
        var scene = new THREE.Scene();
        var camera = new THREE.PerspectiveCamera(75, window.innerWidth/window.innerHeight, 0.1, 1000);
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 创建EffectComposer
        var composer = new THREE.EffectComposer(renderer);
        var renderPass = new THREE.RenderPass(scene, camera);
        composer.addPass(renderPass);

        // 创建自定义后处理ShaderPass
        var myEffect = {
            uniforms: {
                "tDiffuse": { value: null },
                "color": { value: new THREE.Color(0x00ff00) } // 绿色背景
            },
            vertexShader: `
                varying vec2 vUv;
                void main() {
                    vUv = uv;
                    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
                }
            `,
            fragmentShader: `
                uniform vec3 color;
                uniform sampler2D tDiffuse;
                varying vec2 vUv;
                void main() {
                    vec4 previousPassColor = texture2D(tDiffuse, vUv);
                    gl_FragColor = vec4(color, 1.0) * previousPassColor;
                }
            `
        };

        var myPass = new THREE.ShaderPass(myEffect);
        myPass.renderToScreen = true;
        composer.addPass(myPass);

        // 动画循环渲染
        function animate() {
            requestAnimationFrame(animate);
            composer.render();
        }

        animate();
    </script>
</body>
</html>

Output:

在HTML中更改three.js背景为透明或其他颜色

由于篇幅限制,以上是部分示例代码,每个示例都是独立的,可以直接在HTML文件中运行。这些示例展示了如何在three.js中更改背景颜色或设置为透明,并且每个示例都包含了how2html.com字符串。通过这些示例,你可以学习到如何在three.js中使用不同的技术来更改场景的背景。

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