## gerstnerWave (`lygia`/`generative`/`gerstnerWave`)

Gerstner Wave generator based on this tutorial https://catlikecoding.com/unity/tutorials/flow/waves/

Dependencies:

Use:

``````<vec3> gerstnerWave (<vec2> uv, <vec2> dir, <float> steepness, <float> wavelength, <float> _time [, inout <vec3> _tangent, inout <vec3> _binormal] )
``````
``````<vec3> gerstnerWave (<vec2> uv, <vec2> dir, <float> steepness, <float> wavelength, <float> _time [, inout <vec3> _normal] )
``````

Check it on Github

``````

#ifndef FNC_GERSTNERWAVE
#define FNC_GERSTNERWAVE

vec3 gerstnerWave (in vec2 _uv, in vec2 _dir, in float _steepness, in float _wavelength, in float _time, inout vec3 _tangent, inout vec3 _binormal) {
float k = 2.0 * PI / _wavelength;
float c = sqrt(9.8 / k);
vec2 d = normalize(_dir);
float f = k * (dot(d, _uv) - c * _time);
float a = _steepness / k;

_tangent += vec3(
-d.x * d.x * (_steepness * sin(f)),
d.x * (_steepness * cos(f)),
-d.x * d.y * (_steepness * sin(f))
);
_binormal += vec3(
-d.x * d.y * (_steepness * sin(f)),
d.y * (_steepness * cos(f)),
-d.y * d.y * (_steepness * sin(f))
);
return vec3(
d.x * (a * cos(f)),
a * sin(f),
d.y * (a * cos(f))
);
}

vec3 gerstnerWave (in vec2 _uv, in vec2 _dir, in float _steepness, in float _wavelength, in float _time, inout vec3 _normal) {
vec3 _tangent = vec3(0.0);
vec3 _binormal = vec3(0.0);
vec3 pos = gerstnerWave (_uv, _dir, _steepness, _wavelength, _time, _tangent, _binormal);
_normal = normalize(cross(_binormal, _tangent));
return pos;
}

vec3 gerstnerWave (in vec2 _uv, in vec2 _dir, in float _steepness, in float _wavelength, in float _time) {
vec3 _tangent = vec3(0.0);
vec3 _binormal = vec3(0.0);
return gerstnerWave (_uv, _dir, _steepness, _wavelength, _time, _tangent, _binormal);
}

#endif
``````

Dependencies:

Use:

``````<float3> gerstnerWave (<float2> uv, <float2> dir, <float> steepness, <float> wavelength, <float> _time [, inout <float3> _tangent, inout <float3> _binormal] )
``````
``````<float3> gerstnerWave (<float2> uv, <float2> dir, <float> steepness, <float> wavelength, <float> _time [, inout <float3> _normal] )
``````

Check it on Github

``````

#ifndef FNC_GERSTNERWAVE
#define FNC_GERSTNERWAVE

float3 gerstnerWave (in float2 _uv, in float2 _dir, in float _steepness, in float _wavelength, in float _time, inout float3 _tangent, inout float3 _binormal) {
float k = 2.0 * PI / _wavelength;
float c = sqrt(9.8 / k);
float2 d = normalize(_dir);
float f = k * (dot(d, _uv) - c * _time);
float a = _steepness / k;

_tangent += float3(
-d.x * d.x * (_steepness * sin(f)),
d.x * (_steepness * cos(f)),
-d.x * d.y * (_steepness * sin(f))
);
_binormal += float3(
-d.x * d.y * (_steepness * sin(f)),
d.y * (_steepness * cos(f)),
-d.y * d.y * (_steepness * sin(f))
);
return float3(
d.x * (a * cos(f)),
a * sin(f),
d.y * (a * cos(f))
);
}

float3 gerstnerWave (in float2 _uv, in float2 _dir, in float _steepness, in float _wavelength, in float _time, inout float3 _normal) {
float3 _tangent = float3(0.0, 0.0, 0.0);
float3 _binormal = float3(0.0, 0.0, 0.0);
float3 pos = gerstnerWave (_uv, _dir, _steepness, _wavelength, _time, _tangent, _binormal);
_normal = normalize(cross(_binormal, _tangent));
return pos;
}

float3 gerstnerWave (in float2 _uv, in float2 _dir, in float _steepness, in float _wavelength, in float _time) {
float3 _tangent = float3(0.0, 0.0, 0.0);
float3 _binormal = float3(0.0, 0.0, 0.0);
return gerstnerWave (_uv, _dir, _steepness, _wavelength, _time, _tangent, _binormal);
}

#endif
``````