cocos-creator-template/assets/chunks/common/math/number.chunk

#if __VERSION__ <= 100
bool isnan(float val) {
  return (val < 0.0 || 0.0 < val || val == 0.0) ? false : true;
}
bool isinf(float x) {
  return x == x * 2.0 && x != 0.0;
}
#endif

bool isnans(vec2 val) {
    return isnan(val.x) || isnan(val.y);
}
bool isnans(vec3 val) {
    return isnan(val.x) || isnan(val.y) || isnan(val.z);
}
bool isnans(vec4 val) {
    return isnan(val.x) || isnan(val.y) || isnan(val.z) || isnan(val.w);
}

bool isinfs(vec2 val) {
    return isinf(val.x) || isinf(val.y);
}
bool isinfs(vec3 val) {
    return isinf(val.x) || isinf(val.y) || isinf(val.z);
}
bool isinfs(vec4 val) {
    return isinf(val.x) || isinf(val.y) || isinf(val.z) || isinf(val.w);
}


// intrinsic functions
#if __VERSION__ < 300
  float round(float value)   {
      float f = fract(value);
      return value - f + (f < 0.5 ? 0.0 : 1.0);
  }
  vec2 round(vec2 value) { return vec2(round(value.x), round(value.y)); }
  vec3 round(vec3 value) { return vec3(round(value.x), round(value.y), round(value.z)); }
  vec4 round(vec4 value) { return vec4(round(value.x), round(value.y), round(value.z), round(value.w)); }
#endif

float rsqrt(float value) { return 1.0 / sqrt(value); }
vec2 rsqrt(vec2 value) { return vec2(1.0) / sqrt(value); }
vec3 rsqrt(vec3 value) { return vec3(1.0) / sqrt(value); }
vec4 rsqrt(vec4 value) { return vec4(1.0) / sqrt(value); }


// random number
// seeds value must be between zero to one, otherwise get 0
// such as fract(cc_time.z * FSInput_texcoord)
float rand(vec2 seeds_zero_to_one) {
    return fract(sin(dot(seeds_zero_to_one.xy, vec2(12.9898, 78.233))) * 43758.5453);
}

// like smoothstep, but it's linear interpolation
float linearstep(float minValue, float maxValue, float value) { return saturate((value - minValue) / (maxValue - minValue)); }
vec2 linearstep(vec2 minValue, vec2 maxValue, vec2 value) { return saturate((value - minValue) / (maxValue - minValue)); }
vec3 linearstep(vec3 minValue, vec3 maxValue, vec3 value) { return saturate((value - minValue) / (maxValue - minValue)); }
vec4 linearstep(vec4 minValue, vec4 maxValue, vec4 value) { return saturate((value - minValue) / (maxValue - minValue)); }


#if __VERSION__ <= 100
  mat4 transpose(mat4 v) {
    mat4 tmp;
    tmp[0] = vec4(v[0].x, v[1].x, v[2].x, v[3].x);
    tmp[1] = vec4(v[0].y, v[1].y, v[2].y, v[3].y);
    tmp[2] = vec4(v[0].z, v[1].z, v[2].z, v[3].z);
    tmp[3] = vec4(v[0].w, v[1].w, v[2].w, v[3].w);
    return tmp;
  }
#endif