gistfile1.cpp

  void renderLatencyTestSquare() {
    OVR::Color colorToDisplay;

    // If this returns a non-0 value, we're performing a latency
    // test and must render a colored square underneath the tester 
    // (On the lens axis)
    if (ovrLatencyTest.DisplayScreenColor(colorToDisplay)) {
      latencyTestProgram->use();
      latencyTestProgram->setUniform("Color", Rift::fromOvr(colorToDisplay));

      gl::MatrixStack & mv = gl::Stacks::modelview();
      glDisable(GL_DEPTH_TEST);
      mv.with_push([&]{
        mv.identity().translate(glm::vec3(0, 0, -0.1f)).scale(0.005f);
        GlUtils::renderGeometry(latencyTestQuad, latencyTestProgram);
      });
      glEnable(GL_DEPTH_TEST);
    }
  }