Hello.

I am trying to add a vertex shader dynamically to an animated 3D model in dddance.party

It is safe to say, I have no idea what I am doing : U

```
function AddVertexDisplacement(shader) {
var newUniforms = {
time: {
value: 0
},
step: {
value: 0
},
x_active: {
value: 0
},
x_ampl: {
value: 0
},
y_active: {
value: 0
},
y_ampl: {
value: 0
},
z_active: {
value: 0
},
z_ampl: {
value: 0
},
freq:{
value: 0
}
};
$.extend(shader.uniforms, newUniforms);
console.log(shader.uniforms);
shader.vertexShader = 'uniform float time;\n uniform float step;\n uniform float speed, x_active, y_active, z_active, x_ampl, y_ampl, z_ampl, freq; \n' + shader.vertexShader;
shader.vertexShader = shader.vertexShader.replace(
'#include <begin_vertex>',
[
'float pi = 3.14159265358979323846;',
// 'float theta = sin( step + abs(10.*position.x)) / 10.0;',
// 'float theta2 = sin( step + abs(10.*position.x + pi/2.)) / 10.0;',
// 'theta = position.x/10.;',
// 'float c = cos( theta );',
// 'float s = sin( theta );',
// 'float c2 = cos( theta2 );',
// 'float s2 = sin( theta2 );',
// 'mat3 mx = mat3( 1, 0, 0, 0, c, -s, 0, s, c );',
// 'mat3 my = mat3( c, 0, s, 0, 1, 0, -s, 0, c );',
// 'mat3 mz = mat3(c2, -s2, 0, s2, c2, 0, 0, 0, 1);',
// 'mat3 m = my;',
'vec3 transformed = position;',
// 'transformed = vec3( transformed ) * m*mz;',
'float p = 1.;',
'float q = 1.;',
// 'time *= ',
'float tx = step + 3.*freq*( position.x/(2.*pi));',
'float r = cos(q*tx);',
'float x = r*cos(p*tx);',
'float y = r*sin(p*tx);',
'float z = -sin(q*tx);',
'transformed.x += x_active * x_ampl* x;',
'transformed.y += y_active * y_ampl * y;',
'transformed.z += z_active * z_ampl * z;',
// 'transformed.z += z;',
// 'transformed = transformed.xzy;',
// 'vNormal = vNormal * m;'
].join('\n')
);
```

}

^^ here is my shader

```
var WAVY_MATERIAL0 = new THREE.MeshPhongMaterial({
color: 0xffffff,
shininess: 0,
specular: 0xffffff,
skinning: true
});
dancers[0].wavy_material = WAVY_MATERIAL0;
WAVY_MATERIAL0.onBeforeCompile = (shader) => { // trouble :(
AddVertexDisplacement(shader);
dancers[0].wavy_shader = shader;
};
```

^^ here is my code to setup shader.

```
if( USE_SHADER ){ //set vertex shader on phong materials
avatar.traverse( function ( child ) {
if ( child instanceof THREE.Object3D ) {
if(child.material !== undefined){
dancers[idx].wavy_material.map = child.material.map;
dancers[idx].wavy_material.name = child.material.name;
child.material = dancers[idx].wavy_material;
}
}
});
}
```

^^ here is my code to add shader to model, after it loads.

I tried a few things but get a lot of strange behavior. I know the shader works because I can add it to models that are not loaded dynamically.

This seems very complicated. Maybe someone knows an easy solution here? This onBeforeCompile is bizarre.

Thanks.