code: public void setVec2(String key, float x, float y)
      {
          checkKeyIsUniform(key);
          NativeShaderData.setVec2(getNative(), key, x, y);
      }
docs: Set the value for a floating point vector of length 2.
  @param key name of uniform to set.
  @param x new X value
  @param y new Y value
  @see #getVec2
  @see #getFloatVec(String)