webgl实现canvas三维纸张椎体旋转效果代码-html代码-BFW代码库

webgl实现canvas三维纸张椎体旋转效果代码

代码语言：html

所属分类：三维

代码描述：webgl实现canvas三维纸张椎体旋转效果代码

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">
  

  
  
  
<style>
* {
    box-sizing: border-box;
  }
  
  html, body {
    margin: 0;
    min-height: 100vh;
    overflow: hidden;
    
    background:
    repeating-radial-gradient(
    circle at center,
      #444 0 10%,
      #111 10% 20%
    );
    
    touch-action: none;
  }
  
  canvas {
    width: 100%;
    height: auto;
    object-fit: contain;
  }
</style>



</head>

<body>
  <canvas id="canvas"></canvas>

  
      <script >
/*********
 * made by Matthias Hurrle (@atzedent)
 */

/** @type {HTMLCanvasElement} */
const canvas = window.canvas;
const gl = canvas.getContext("webgl2");
const dpr = Math.max(1, .5 * window.devicePixelRatio);
/** @type {Map<string,PointerEvent>} */
const touches = new Map();

const vertexSource = `#version 300 es
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif

in vec2 position;

void main(void) {
    gl_Position = vec4(position, 0., 1.);
}
`;
const fragmentSource = `#version 300 es
/*********
* made by Matthias Hurrle (@atzedent)
*/

#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif

uniform float time;
uniform vec2 resolution;
uniform vec2 touch;
uniform int pointerCount;

out vec4 fragColor;

#define T (mod(time+5., 200.))
#define S smoothstep
#define mouse (touch/resolution)
#define rot(a) mat2(cos(a),-sin(a),sin(a),cos(a))
float oct(vec3 p, float s) {
    p = abs(p);

    return (p.x+p.y+p.z-s)*(1./sqrt(3.));
}

float mat=1.;
float map(vec3 p) {
    vec3 q = p;
    q.xz *= rot(-T*.5);
    q.yz *= rot(T*.25);
    float d = 1e5,
    oc0=oct(q, 1.75),
    flr = p.y+3.+sin(T+p.x+sin(p.xz*rot(.5678)).x)*.5;

    d=min(d,oc0);
    d=min(d,flr);
    
    if(d==oc0) mat=.0;
    else mat=1.;

    return d;
}

vec3 norm(vec3 p) {
    vec2 e=vec2(1e-2,0);
    float d=map(p);
    vec3 n=d-vec3(
        map(p-e.xyy),
        map(p-e.yxy),
        map(p-e.yyx)
    );

    return normalize(n);
}

float getshadow(vec3 ro, vec3 rd) {
    const float steps=10., k=64.;
    float shade=1.;

    for(float i=1e-3;i<steps;) {
        float d=map(ro+rd*i);

        if(d<1e-3) {
            shade=5e-3;
            break;
        }

        shade=min(shade, k*d/i);

        i+=d;
    }

    return shade;
}

float getao(vec3 p, vec3 n, float dist) {
    return clamp(map(p+n*dist)/dist,.0,1.);
}

void cam(inout vec3 p) {
    if(pointerCount>0) {
        p.yz*=rot(-clamp(mouse.y,-1.,.5)*acos(-1.)+acos(.0));
        p.xz*=rot(-mouse.x*acos(-1.)*2.);
    } else {
        p.yz*=rot(sin(T*.5)*.25+.25);
        p.xz*=rot(T*.25);
        p.xy*=rot(sin(T*.5)*.25+.25);
    }
}

void main(void) {
    vec2 uv = (
        gl_FragCoord.xy-.5*resolution.xy
    )/min(resolution.x,resolution.y);

    vec3 col = vec3(0),
    ro=vec3(0,0,2.*exp(-cos(T*.25))-10.),
    rd=normalize(vec3(uv,1));

    cam(ro);
    cam(rd);

    vec3 p=ro,
    l=normalize(vec3(1,2,3));

    const float steps=100.,maxd=20.;
    float i=.0, dd=.0, edge=.0;
    bool near=false;

    for(;i<steps;i++) {
        float d=map(p)*.5;

        if(d<1e-3) break;

        if(near && d>3e-2) {
            edge=1.;
            break;
        }

        if(d<2e-2) {
            near=true;
        }

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