michelez

I am struggling to find a function to calculate normals in jit.gl.pix.

Within the codebox I have points as vec(x,y,z) and an algorithm to translate them into a 3d -like rendering. Now I am trying to give these points some lighting. I would like to keep it into the jit.gl.pix world since I want to keep it as neat and efficient as possible.

I think I found something close to what I need in the juilia.quat.raytracer.maxpat (see below): basically calculating a derivative for each point and get the normal from there. I am not sure this would take into account my third dimension for each point, in fact I don't think it would. Any idea how to do this?

        mz = vec(z.x,-z.y,-z.z,-z.w);

        dz0 = concat(dot(mz,dz0), z.x*dz0.yzw + dz0.x*z.yzw);

        dz1 = concat(dot(mz,dz1), z.x*dz1.yzw + dz1.x*z.yzw);

        dz2 = concat(dot(mz,dz2), z.x*dz2.yzw + dz2.x*z.yzw);

I am struggling to find a function to calculate normals in jit.gl.pix.
Within the codebox I have points as vec(x,y,z) and an algorithm to translate them into a 3d -like rendering. Now I am trying to give these points some lighting. I would like to keep it into the jit.gl.pix world since I want to keep it as neat and efficient as possible.
I think I found something close to what I need in the juilia.quat.raytracer.maxpat (see below): basically calculating a derivative for each point and get the normal from there. I am not sure this would take into account my third dimension for each point, in fact I don't think it would. Any idea how to do this?

 

calcNormal(p, c) {
    z = concat(p, (c.y+c.x)*0.3);
	dz0 = vec(1.0,0.0,0.0,0.0);
	dz1 = vec(0.0,1.0,0.0,0.0);
	dz2 = vec(0.0,0.0,1.0,0.0);

	for(i=0; i < 9; i+=1.) {
		mz = vec(z.x,-z.y,-z.z,-z.w);
		// derivative
		dz0 = concat(dot(mz,dz0), z.x*dz0.yzw + dz0.x*z.yzw);
		dz1 = concat(dot(mz,dz1), z.x*dz1.yzw + dz1.x*z.yzw);
		dz2 = concat(dot(mz,dz2), z.x*dz2.yzw + dz2.x*z.yzw);
 

       // z = z2 + c
		nz = concat(
			dot(z, mz),
			2.0*z.x*z.yzw
		);
		z = nz+c;

   return normalize(vec(
		dot(z,dz0),
		dot(z,dz1),
		dot(z,dz2)
	));
}

Hello!
I am struggling to find a function to calculate normals in jit.gl.pix.
Within the codebox I have points as vec(x,y,z) and an algorith