Fragment shader on plane with modified vertices

Question

I have a PlaneGeometry and I\'m randomly animating the vertices in order to create random spikes. I use this FragmentShader :

void main() {
       vec3 light = v         


        

Answer 1

Your "spikes" do not have different vertex normals because you didn't change the vertex normals; they are all ( 0, 1, 0 ). This is something you could have checked yourself in the console.

Also, when you modify the vertices of a quad ( a face of the plane ), the four vertices are likely no longer planar. This will cause you all sorts of problems. ( google non-planar quads. )

You can avoid these problems by triangulating the PlaneGeometry first:

THREE.GeometryUtils.triangulateQuads( geometry );

Be advised that this function recomputes vertex normals. Have a look at the source so you understand what it is doing.

three.js r.58