webgl+canvas实现GLSL 着色器振荡梯度动画效果代码-html代码-BFW代码库

代码语言：html

所属分类：动画

代码描述：webgl+canvas实现GLSL 着色器振荡梯度动画效果代码

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

<!DOCTYPE html>
<html lang="en" >

<head>
  <meta charset="UTF-8">
  
<link type="text/css" rel="stylesheet" href="//repo.bfw.wiki/bfwrepo/css/reset.min.css">
  
  
<style>
html, body {
  width: 100%; height: 100%; 
  overflow: hidden;
}
canvas {
  display: block;
  width: 100vw; height: 100vh;
  background: #000;
}
</style>

  
</head>

<body translate="no">
  <canvas id="c"></canvas>

<!-- Vertex Shader -->
<script id="vertex-shader" type="x-shader/x-vertex">
    attribute vec2 a_position;
    void main() {
        gl_Position = vec4(a_position, 0, 1);
    }
</script>

<!-- Fragment Shader -->
<script id="fragment-shader" type="x-shader/x-fragment">
    precision mediump float;
    uniform vec3 iResolution;
    uniform float iTime;
    uniform int iFrame;
    uniform sampler2D iChannel0;


    float adjustValue(float value, float progress) {
      float offset = 0.7;

      return tan(value * (1.0 - progress) + offset * progress);
    }

    float whiteNoise(vec2 uv) {
      float x = (uv.x + 0.1) * (uv.y + 0.1);
      return fract(sin(x) * 43758.5453123);
    }

    float fBm(vec2 uv) {
      float sum = 0.0;
      float scale = 1.0;
      float amplitude = 1.0;
      for (int i = 0; i < 4; ++i) {
        sum += whiteNoise(uv * scale) * amplitude;
        scale *= 2.0;
        amplitude *= 0.5;
      }
      return sum;
    }

    void main()
    {
        float grainTileSize = 5.0; // the bigger the number, the finer the grain
        float grainTileOpacity = 0.15; // the opacity of the grain tile
        float frequency = 0.5; // The higher the value, the faster the oscillation
        float amplitude = 0.4; // The range within which to oscillate
        float widthFactor = 3.0; // the width of the color
        float centerValue = 0.15; // center position of the middle color
        bool animateGrain = true;
        float angle = 1.03; // Angle in radians

        vec4 bgColor = vec4(0.0, 0.0, 0.0, 0.0);
        vec4 colors[7];
        colors[0] = vec4(0.0 / 255.0, 0.0 / 255.0, 0.0 / 255.0, 1.0);      // #000000
        colors[1] = vec4(44.0 / 255.0, 56.0 / 255.0, 195.0 / 255.0, 1.0);  // #2C38C3
        colors[2] = vec4(190.0 / 255.0, 191.0 / 255.0, 212.0 / 255.0, 0.78); // rgba(190, 191, 212, 0.78)
        colors[3] = vec4(190.0 / 255.0, 191.0 / 255.0, 212.0 / 255.0, 0.94); // rgba(190, 191, 212, 0.94)
        colors[4] = vec4(206.0 / 255.0, 195.0 / 255.0, 155.0 / 255.0, 0.94); // rgba(206, 195, 155, 0.94)
        colors[5] = vec4(197.0 / 255.0, 158.0 / 255.0, 37.0 / 255.0, 1.0); // #C59E25
        colors[6] = vec4(113.0 / 255.0, 0.0 / 255.0, 64.0 / 255.0, 1.0);  // #710040

        // Gradient stop values for each color
        float originalValues[7];
        originalValues[0] = 0.026;
        originalValues[1] = 0.1027;
        originalValues[2] = 0.1656;
        originalValues[3] = 0.2207;
        originalValues[4] = 0.2579;
        originalValues[5] = 0.319;
        originalValues[6] = 0.4154;

        float gradientStops[7];
        float adjustedValues[7];
        const int MAX_COLORS = 7; // Number of colors


        // Normalized coordinates ([0,1])
        vec2 uv = gl_FragCoord.xy/iResolution.xy;

        // Center the coordinates
        vec2 centeredCoord = uv - vec2(0.5);

        float pulse = amplitude * sin(frequency * iTime) + amplitude;

        float progress = ((1.0 - pulse) / 2.0) + (uv.x * pulse);


        // Rotation matrix
        float cosA = cos(angle);
        float sinA = sin(angle);
        mat2 rotation = mat2(cosA, -sinA, sinA, cosA);

        // Apply rotation to the centered coordinates
        vec2 rotatedCoord = rotation * centeredCoord;

        // Calculate gradient based on rotated x-coordinate
        float gradient = rotatedCoord.x + 0.5;

        // Define colors
        float bgGradientEnd = adjustValue(0.0, progress);


        for(int i = 0; i < MAX_COLORS; i++) {
        // Reverse the order and adjust the original values
          adjustedValues[i] = 0.5 - originalValues[6 - i];
        // Center around centerValue and apply the width factor
          gradientStops[i] = adjustValue(centerValue + (adjustedValues[i] - centerValue) * widthFactor, progress);
        }


        // Interpolate colors based on gradient
        vec4 color = bgColor;

        // Loop through all color stops
        for (int i = 0; i < MAX_COLORS; i++) {
            if (gradient >= gradientStops[i] && gradient < gradientStops[i + 1]) {
                float t = (gradient - gradientStops[i]) / (gradientStops[i + 1] - gradientStops[i]);
                color = mix(colors[i], colors[i + 1], t);
                //color = mix(colors[i], colors[i + 1], smoothstep(gradientStops[i], gradientStops[i + 1], gradient));

                break; // Exit loop once color is determined
            }
        }


        // Handle edge case for the first color stop
        if (gradient >= gradientStops[MAX_COLORS - 1]) {
            //color = mix(bgColor, colors[0], (gradient - bgGradientEnd) / (gradientStops[0] - bgGradien.........完整代码请登录后点击上方下载按钮下载查看