Keyboard Movement

Libraries: GLFW ,SDL2, Qt

GLFW

First create a struct, mapping the keyboard to variables

class KeyboardMovementsController{

  public:
  struct KeyMappings{
    int moveLeft = GLFW_KEY_A;
    int moveRight = GLFW_KEY_D;
    int moveForward = GLFW_KEY_W;
    int moveBackward = GLFW_KEY_S;
    int moveUp = GLFW_KEY_Q;
    int moveDown = GLFW_KEY_E;
    int lookLeft = GLFW_KEY_LEFT;
    int lookRight = GLFW_KEY_RIGHT;
    int lookUp = GLFW_KEY_UP;
    int lookDown = GLFW_KEY_DOWN;
  };

  void moveInPlaneXZ (GLFWwindow *window , float dt, LveGameObject& gameObject);

  KeyMappings keys{}; //create a member variable and initialize it
  float moveSpeed{3.f};
  float lookSpeed{1.5f};

};

Then Implement it

  void KeyboardMovementsController::moveInPlaneXZ (GLFWwindow *window , float dt, LveGameObject& gameObject){

  glm::vec3 rotate{0}; //initialize the rotate as 0

  if (glfwGetKey(window, keys.lookRight) == GLFW_PRESS ) rotate.y += 1.f;
  if (glfwGetKey(window, keys.lookLeft) == GLFW_PRESS ) rotate.y -= 1.f;
  if (glfwGetKey(window, keys.lookUp) == GLFW_PRESS ) rotate.x += 1.f;
  if (glfwGetKey(window, keys.lookDown) == GLFW_PRESS ) rotate.x -= 1.f;

  if (glm::dot(rotate, rotate) > std::numeric_limits<float>::epsilon()){
    gameObject.transform.rotation += lookSpeed * dt * glm::normalize(rotate);
  }

  gameObject.transform.rotation.x = glm::clamp(gameObject.transform.rotation.x , -1.5f, 1.5f);
  gameObject.transform.rotation.y = glm::mod(gameObject.transform.rotation.y , glm::two_pi<float>());

  float yaw = gameObject.transform.rotation.y;
  const glm::vec3 forwardDir{sin(yaw), 0.f, cos(yaw)};
  const glm::vec3 rightDir{forwardDir.z , 0.f, -forwardDir.x}; //the vector perpendicular t o forward direction
  const glm::vec3 upDir{0.f, -1.f, 0.f};
}

glm::two_pi<float>() return constant, the value of 2π
std::numeric_limits<float>::epsilon() return constant. The value is typically very small (around 1.19209e-07 for 32-bit floats).
epsilon(): The difference between 1.0 and the next representable value

for example, the next representable value after 1.0 is 1.00000011920928955078125
so epsilon() is 1.00000011920928955078125 - 1.0 = 0.00000011920928955078125