Merge "Fix the grid artifacts in simplex noise" into main

            return dest;

        }

        // Return range [-1, 1].

        // Integer mod. GLSL es 1.0 doesn't have integer mod :(

        int imod(int a, int b) {

            return a - (b * (a / b));

        }

        ivec3 imod(ivec3 a, int b) {

            return ivec3(imod(a.x, b), imod(a.y, b), imod(a.z, b));

        }

        // Integer based hash function with the return range of [-1, 1].

        vec3 hash(vec3 p) {

            p = fract(p * vec3(.3456, .1234, .9876));

            p += dot(p, p.yxz + 43.21);

            p = (p.xxy + p.yxx) * p.zyx;

            return (fract(sin(p) * 4567.1234567) - .5) * 2.;

            ivec3 v = ivec3(p);

            v = v * 1671731 + 10139267;

            v.x += v.y * v.z;

            v.y += v.z * v.x;

            v.z += v.x * v.y;

            ivec3 v2 = v / 65536; // v >> 16

            v = imod((10 - imod((v + v2), 10)), 10); // v ^ v2

            v.x += v.y * v.z;

            v.y += v.z * v.x;

            v.z += v.x * v.y;

            // Use sin and cos to map the range to [-1, 1].

            return vec3(sin(float(v.x)), cos(float(v.y)), sin(float(v.z)));

        }

        // Skew factors (non-uniform).