js实现canvas液态鼠标跟随动画效果代码-html代码-BFW代码库

代码语言：html

所属分类：动画

代码描述：js实现canvas液态鼠标跟随动画效果代码

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<html>
<head>
    <style>
        body {
            background: #555555;
            margin: 0;
        }

        canvas {
            position: fixed;
        }
    </style>

</head>
<body>
    <canvas id="webgl" width="574" height="611" style="width: 574px; height: 611px;"></canvas>

    <script id="vertexShader" type="x-shader/x-vertex">
        attribute vec4 a_position;

        uniform mat4 u_modelViewMatrix;
        uniform mat4 u_projectionMatrix;

        void main() {
            gl_Position = a_position;
        }
    </script>
    <script id="fragmentShader" type="x-shader/x-fragment">
        #extension GL_OES_standard_derivatives: enable
        precision highp float;

        uniform vec2 u_resolution;
        uniform vec2 u_mouse;
        uniform vec2 u_oldmouse;
        uniform float u_time;
        uniform sampler2D u_noise;

        uniform int u_frame;

        uniform sampler2D u_b_buffer;
        uniform bool u_buffer_pass;

        #define PI 3.141592653589793

        vec2 getScreenSpace() {
            vec2 uv = (gl_FragCoord.xy - 0.5 * u_resolution.xy) / min(u_resolution.y, u_resolution.x);

            return uv;
        }

        float sdSegment(in vec2 p, in vec2 a, in vec2 b) {
            vec2 pa = p-a,
            ba = b-a;
            float h = clamp(dot(pa, ba)/dot(ba, ba), 0.0, 1.0);
            return length(pa - ba*h);
        }

        vec4 render_effect() {
            vec2 uv = getScreenSpace();
            vec2 oldmouse = u_oldmouse.xy;
            vec2 mouse = u_mouse.xy;

            return vec4(vec3(smoothstep(.02, .0, sdSegment(uv, oldmouse, mouse))), 1.);
        }

        vec4 blurBuffer(vec2 uv) {
            vec3 pixs = vec3(1./u_resolution.xy, 0.)*5.;

            vec4 sample = texture2D(u_b_buffer, uv + pixs.zy);
            sample += texture2D(u_b_buffer, uv - pixs.zy);
            sample += texture2D(u_b_buffer, uv + pixs.xz);
            sample += texture2D(u_b_buffer, uv - pixs.xz);

            sample *= .25;

            return sample;
        }

        void main() {
            vec4 tex = texture2D(u_b_buffer, gl_FragCoord.xy/u_resolution.xy);
            tex = blurBuffer(gl_FragCoord.xy/u_resolution.xy);
            if (u_buffer_pass) {
                gl_FragColor = (tex * .9995 + render_effect());
            } else {
                float f = sin(min(10., tex.r));
                f = smoothstep(0., 1., tex.r);
                float tex1 = texture2D(u_b_buffer, gl_FragCoord.xy/u_resolution.xy - 20./u_resolution.xy).r;
                float f1 = sin(min(10., tex1));
                f1 = smoothstep(0., 1., tex1);
                float s = f;
                s = 1. - pow(s, .3);
                s = s*3.;
                float r = smoothstep(0.6, .8, f) - s;
                float g = smoothstep(0.5, .5+fwidth(f), f) - s;
                float b = smoothstep(0.1, .4, f1) - s;
                float sh = clamp(r-b, 0., 1.);
                // sh = smoothstep(0., .8, sh);
                gl_FragColor = vec4(vec3(r-sh*.5), 1.);
            }
        }

    </script>
    <script>
        function _defineProperty(obj, key, value) {
            if (key in obj) {
                Object.defineProperty(obj, key, {
                    value: value, enumerable: true, configurable: true, writable: true
                });
            } else {
                obj[key] = value;
            }return obj;
        } /**
        * A basic Web GL class. This provides a very basic setup for GLSL shader code.
        * Currently it doesn't support anything except for clip-space 3d, but this was
        * done so that we could start writing fragments right out of the gate. My
        * Intention is to update it with particle and polygonal 3d support later on.
        *
        * @class WTCGL
        * @author Liam Egan <liam@wethecollective.com>
        * @version 0.0.8
        * @created Jan 16, 2019
        */
        class WTCGL {

            /**
            * The WTCGL Class constructor. If construction of the webGL context fails
            * for any reason this will return null.
            *
            * @TODO make the dimension properties properly optional
            * @TODO provide the ability to allow for programmable buffers
            *
            * @constructor
            * @param {HTMLElement} el The canvas element to use as the root
            * @param {string} vertexShaderSource The vertex shader source
            * @param {string} fragmentShaderSource The fragment shader source
            * @param {number} [width] The width of the webGL context. This will default to the canvas dimensions
            * @param {number} [height] The height of the webGL context. This will default to the canvas dimensions
            * @param {number} [pxratio=1] The pixel aspect ratio of the canvas
            * @param {boolean} [styleElement] A boolean indicating whether to apply a style property to the canvas (resizing the canvas by the inverse of the pixel ratio)
            * @param {boolean} [webgl2] A boolean indicating whether to try to create a webgl2 context instead of a regulart context
            */
            constructor(el, vertexShaderSource, fragmentShaderSource, width, height, pxratio, styleElement, webgl2, params = {}) {
                this.run = this.run.bind(this);

                this._onRun = () => {};

                // Destructure if an object is aprovided instead a series of parameters
                if (el instanceof Object && el.el) {
                    ({
                        el, vertexShaderSource, fragmentShaderSource, width, height, pxratio, webgl2, styleElement
                    } = el);
                }

                // If the HTML element isn't a canvas, return null
                if (!el instanceof HTMLElement || el.nodeName.toLowerCase() !== 'canvas') {
                    console.log('Provided element should be a canvas element');
                    return null;
                }

                this._el = el;
                // The context should be either webgl2, webgl or experimental-webgl
                if (webgl2 === true) {
                    this.isWebgl2 = true;
                    this._ctx = this._el.getContext("webgl2", this.webgl_params) || this._el.getContext("webgl", this.webgl_params) || this._el.getContext("experimental-webgl", this.webgl_params);
                } else {
                    this.isWebgl2 = false;
                    this._ctx = this._el.getContext("webgl", Object.assign({}, this.webgl_params, params)) || this._el.getContext("experimental-webgl", Object.assign({}, this.webgl_params, params));
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