code: public void setVec3(String key, float x, float y, float z)
      {
          checkKeyIsUniform(key);
          NativeLight.setVec3(getNative(), key, x, y, z);
      }
docs: Set the value for a floating point vector of length 3.
  @param key name of uniform to set.
  @param x new X value
  @param y new Y value
  @param z new Z value
  @see #getVec3
  @see #getFloatVec(String)