yiwenl

vec4 when_eq(vec4 x, vec4 y) {
  return 1.0 - abs(sign(x - y));
}

vec4 when_neq(vec4 x, vec4 y) {
  return abs(sign(x - y));
}

vec4 when_gt(vec4 x, vec4 y) {
  return max(sign(x - y), 0.0);

yiwenl

vec2 rotate(vec2 v, float a) {
	float s = sin(a);
	float c = cos(a);
	mat2 m = mat2(c, s, -s, c);
	return m * v;
}

yiwenl

const dropArea = window;

const preventDefaults = (e)=> {
	e.preventDefault()
	e.stopPropagation();
}

;['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
	dropArea.addEventListener(eventName, preventDefaults, false);
})

yiwenl

// compression.js
const defaultPrecision = 10;

const encode = (a, b, mPrecision=defaultPrecision) => {
	const precision = mPrecision;
	const base = Math.floor(Math.sqrt(Math.pow(93, precision)));

	let lat = a, lng = b;
	let lng935 = Math.floor( ( parseFloat(lng) +180)*base/360 );
	let lat935 = Math.floor( ( parseFloat(lat) +90)*base/180 );

yiwenl

// saveImage.js

const dataURLtoBlob = (dataurl) => {
    var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
    while(n--){
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], {type:mime});
}

yiwenl

// fov in Radians, camera position in [x, y, z]
const fovHeight = Math.tan(camera.fov / 2) * camera.position[2]  
const fovWidth = fovHeight * camera.aspectRatio

yiwenl

float map(float value, float start, float end, float newStart, float newEnd) {
  float percent = (value - start) / (end - start);
  if (percent < 0.0) {
    percent = 0.0;
  }
  if (percent > 1.0) {
    percent = 1.0;
  }
  float newValue = newStart + (newEnd - newStart) * percent;
  return newValue;

yiwenl

// bezier curve with 2 control points
// A is the starting point, B, C are the control points, D is the destination
// t from 0 ~ 1
vec3 bezier(vec3 A, vec3 B, vec3 C, vec3 D, float t) {
  vec3 E = mix(A, B, t);
  vec3 F = mix(B, C, t);
  vec3 G = mix(C, D, t);

  vec3 H = mix(E, F, t);
  vec3 I = mix(F, G, t);

yiwenl

vec3 align(vec3 pos, vec3 dir) {
    vec3 initDir = vec3(1.0, 0.0, 0.0);
    vec3 axis = cross(dir, initDir);
    float angle = acos(dot(dir, initDir));
    return rotate(pos, axis, angle);
}

yiwenl

uniform float zNear = 0.1;
uniform float zFar = 500.0;

// depthSample from depthTexture.r, for instance
float linearDepth(float depthSample)
{
    depthSample = 2.0 * depthSample - 1.0;
    float zLinear = 2.0 * zNear * zFar / (zFar + zNear - depthSample * (zFar - zNear));
    return zLinear;
}