3D / FPS Camera Issues - SDL2 - c++

Question

I got a problem with my code, I'm trying to make a First Person 3D Camera.
I use SDL_GetKeyboardState(NULL) to get the pressed keys.
When I press one of the defined keys nothing happens, why?
Camera (Controll):
void Control(float movevel, float mousevel, bool mi, SDL_Window* window)
{
if (mi) //if the mouse is in the screen
{
int MidX = 640 / 2; //middle of the screen
int MidY = 480 / 2;
SDL_ShowCursor(SDL_DISABLE); //we don't show the cursor
int tmpx, tmpy;
SDL_GetMouseState(&tmpx, &tmpy); //get the current position of the cursor
camYaw += mousevel*(MidX - tmpx); //get the rotation, for example, if the mouse current position is 315, than 5*0.2, this is for Y
camPitch += mousevel*(MidY - tmpy); //this is for X
lockCamera();
//SDL_WarpMouse(MidX, MidY); //move back the cursor to the center of the screen
SDL_WarpMouseInWindow(window, MidX, MidY);
const Uint8* kstate = SDL_GetKeyboardState(NULL);
if (kstate[SDLK_w])
{
if (camPitch != 90 && camPitch != -90)
{ //if we are facing directly up or down, we don't go forward, it will be commented out, when there will be gravity
moveCamera(movevel, 0.0); //move forward
}
moveCameraUp(movevel, 0.0); //move up/down
}
if (kstate[SDLK_s])
{
//same, just we use 180 degrees, so we move at the different direction (move back)
if (camPitch != 90 && camPitch != -90)
{
moveCamera(movevel, 180.0);
}
moveCameraUp(movevel, 180.0);
}
if (kstate[SDLK_a])
{ //move left
moveCamera(movevel, 90.0);
}
if (kstate[SDLK_d])
{ //move right
moveCamera(movevel, 270);
}
}
glRotatef(-camPitch, 1.0, 0.0, 0.0);
glRotatef(-camYaw, 0.0, 1.0, 0.0);
}
Main (Loop)
while (running)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
SDL_Event ev;
while (SDL_PollEvent(&ev))
{
switch (ev.type)
{
case SDL_QUIT:
running = false;
break;
case SDL_KEYDOWN:
int x, y;
SDL_GetMouseState(&x, &y);
Main::handleKeys(ev.key.keysym.scancode, x, y);
break;
}
}
Main::update(window);
Main::render(window);
SDL_GL_SwapWindow(window);
}
Main (Update):
void Main::update(SDL_Window* window)
{
Control(0.2, 0.2, mousein, window);
UpdateCamera(0.2); //move the camera to the new location
}

Answer 1

you should call the glRotatef functions before you translate the camera, otherwise it will be rotated about the origin and not its position

Answer 2

Use SDL_PumpEvents() to update the state array. (From the SDL_GetKeyboardState() wiki).
I believe that if you do:
SDL_PumpEvents();
SDL_GetKeyboardState(NULL);
you should get the results you are looking for. (You need to SDL_PumpEvents every loop as well as SDL_GetKeyboardState obviously)
(EDIT)
Another option:
case SDL_KEYDOWN:
switch(event.key.keysym.sym){
case SDLK_w
(... code)
break;
case SDLK_s:
(... code)
break;
case SDLK_a:
(... code)
break;
case SDLK_d:
(... code)
break;
You can also send the event.key.keysym.sym to a function and use it their ofcourse.