So I'm trying to make a keyboard handler for a side project that I'm making in SDL2. After searching around the web a bit for some help this is what I came up with.
bool Keys[322];
void init() override {
for (bool i : Keys) {
i = false;
}
}
void update() override {
if (CRS::event.type == SDL_KEYDOWN) {
Keys[CRS::event.key.keysym.sym] = true;
}
if (CRS::event.type == SDL_KEYUP) {
Keys[CRS::event.key.keysym.sym] = false;
}
if (Keys[SDLK_w]) {
Transform->Velocity.y = 0; //moves the player up
}
}
This code above works fine most of the time, but the problem occurs whenever I try to use any keys SDL considers a modifier (such as left shift, capslock, ctrl, alt, etc). Whenever I even touch one of those buttons I get a Access violation reading location error. Can anyone tell me why that is? And if I wanted to use shift, capslock, etc how would I go about doing that?
So i've decided to scrap my code after realizing that this probably isn't how I want to implement what I wanted and used the SDL_GetKeyboardStates function instead, which worked like a charm.
Related
I am trying to make a program where you are allowed to select between an option of shapes, and then drawing it. To allow for multiple shapes I created a vector of a class which creates shapes (Shapes are set up with the chosen function). My problem is the mouse click is too long, so it assigns it to everything in the vector, so you can't create a new shape. Is there a problem in my logic, or is there a problem in the code?
Here is my attempt:
for (auto& it : onCanvas) {
if (Mouse::isButtonPressed(Mouse::Left)) {
if (mousepointer.getGlobalBounds().intersects(circleOption.getGlobalBounds())) {
it.chosen(circles);
}
if (mousepointer.getGlobalBounds().intersects(rectOption.getGlobalBounds())) {
it.chosen(rectangle);
}
if (mousepointer.getGlobalBounds().intersects(triOption.getGlobalBounds())) {
it.chosen(triangles);
}
if (mousepointer.getGlobalBounds().intersects(it.shape.getGlobalBounds()) || it.dragging) {
it.shape.setPosition(mousepointer.getPosition());
it.dragging = true;
}
}
if (!Mouse::isButtonPressed) {
it.dragging = false;
}
win.draw(it.shape);
}
Your source-code is a bit incomplete (what is onCanvas and mousepointer). But I guess the problem is that this snippet is called multiple times while your mouse is clicked. To avoid that you can do two thing.
In the first solution you use events, so you only add shapes when the state of the mousebutton changes (you can additionally listen to the MouseButtonReleased to simulate a full click):
if (event.type == sf::Event::MouseButtonPressed)
{
if (event.mouseButton.button == sf::Mouse::Left)
{
// Hit Detection
}
}
or second solution you remember the last state of the button (probably do the mouse check once outside of the for loop):
bool mouse_was_up = true;
if (mouse_was_up && Mouse::isButtonPressed(Mouse::Left)) {
mouse_was_up = false;
for (auto& it : onCanvas) {
// Hit Detection
}
}
else if (!Mouse::isButtonPressed(Mouse::Left))
mouse_was_up = true;
I would rather stick to the first solution because when your click is too short and your gameloop is in another part of the game logic, you can miss the click.
UPDATE:Check my answer for details, pointer error.
I have a function, that is supposed to load a few test assets and blit them onto screen using SDL2. This function throws a segfault immediately before executing any commands, with no clear cause. Keep in mind that some of the variables in this function are globals.
Function contents:
printf("DEBUG");
int menuSelect = 0;
printf("declare");
SDL_Surface* bg = SDL_LoadBMP("menubg.bmp");
printf("bg load");
SDL_Surface* menu1 = TTF_RenderText_Solid(font,"HACKING PROGRAM",whiteclr);
printf("title blip");
SDL_BlitSurface(bg,NULL,screen,NULL);
printf("event");
SDL_Event* event;
printf("menu2");
SDL_Surface* menu2 = TTF_RenderText_Solid(font,"Hack",whiteclr);
printf("rect");
SDL_Rect menu2r = CreateRect(5,30,menu2->w,menu2->h);
printf("free");
SDL_FreeSurface(menu2);
SDL_FreeSurface(menu1);
while(SDL_WaitEvent(event))
{
switch(event->type)
{
case SDL_MOUSEBUTTONDOWN:
if(event->motion.x > menu2r.x && event->motion.x < menu2r.x+menu2r.w && event->motion.y > menu2r.y && event->motion.y < menu2r.y+menu2r.h)
{
SDL_FreeSurface(bg);
return 0;
}
break;
case SDL_MOUSEMOTION:
if(event->motion.x > menu2r.x && event->motion.x < menu2r.x+menu2r.w && event->motion.y > menu2r.y && event->motion.y < menu2r.y+menu2r.h)
{
menuSelect=1;
}
else
{
menuSelect=0;
}
break;
}
if(menuSelect==1)
{
menu2 = TTF_RenderText_Solid(font,"Hack",selectclr);
}
else
{
menu2 = TTF_RenderText_Solid(font,"Hack",selectclr);
}
}
return 0;
Double check the paths on fonts, images, etc. Are they correct in relation to the root directory of the project? They are quite sensitive. To avoid simple mistakes like these: go to point 2.
Apply some basic exception handling. For example:
SDL_Surface* bg = SDL_LoadBMP("menubg.bmp");
if(bg == NULL)
{
// This code will be run when menubg.bmp cannot be loaded.
}
It's good practice to always check the outcome of your statement to make sure it worked as planned.
Use a debugger. GDB is the most popular one; but I personally use DDD, a visual debugger that is run on GDB. It's very lightweight and has both graphical and console input.
Document your code. Even if it's a personal project and you're not going to show it to anyone. Explain what each statement does and why it's needed; you'll get a clearer sense of the code and you may find the problem itself.
Also, it's while(SDL_WaitEvent(&event)) not while(SDL_WaitEvent(event)).
This is actually a stupid error, and something that might happen to anyone who is a newbie to SDL. WaitEvent(SDL_Event*) should be fed &event, as in event should be the event, not a pointer to the event. By changing while(SDL_WaitEvent(event)) to while(SDL_WaitEvent(&event)) and changing SDL_Event* event; to SDL_Event event; this problem is fixed.
For anyone else experiencing any kind of segfault, debugging hard will do the job. The guys here at SO greatly helped me in tracing down and fixing my stupid error, and educated me as a developer.
The code I've written displays the sf::Drawable objects only for the top state of the state stack. Rendering works fine for everything, except the sf::Text type, that does not change the color of the text when button.getText().setFillColor(sf::Color:Red) is called. However, when I construct a button with a red text, whenever I try to set another color to that button, I only get a white text, no matter what color I request.
Here's where I change the color of a button:
void GameState_MainMenu::handleRealTimeInput()
{
for each (TextButton button in mButtons)
{
if (button.isSpriteClicked())
{
button.getText().setFillColor(sf::Color::Red);
button.triggerAction();
sf::Clock wait;
sf::Time timer = sf::Time::Zero;
timer = sf::seconds(0.15f);
while (wait.getElapsedTime() < timer)
{
}
wait.restart();
}
}
}
and this is my Game::render() method:
void Game::render()
{
GameState *currentState = getActiveState();
if (currentState != nullptr)
{
mWindow.clear();
currentState->draw();
}
mWindow.display();
}
Lastly, this is the draw method of the MainMenu state:
void GameState_MainMenu::draw()
{
game->mWindow.draw(game->mBackground);
game->mWindow.draw(mSelector.mSprite);
for each (TextButton button in mButtons)
{
game->mWindow.draw(button.getText());
}
}
It's probably because you have a while loop in the GameState_MainMenu::handleRealTimeInput that the program is getting stuck in.
You can try to use threads, though that way could get pretty messy. I suggest revising your code.
Okay, so I figured out this had something to do with c++'s for each instruction. As soon as I switched to the classic array-like traversal, my buttons started changing colors. I'm not saying this is THE solution, just that it worked for me. If anyone has the same problem, you might want to check that.
I am trying to make my basic loading screen transition over to game level screen. So what i wanted to do is, once the loading screen is active (or has appeared onscreen), I want at this point to start loading my game state. What it is doing at the moment is loading everything at the start, and this does take a while.
So currently my project starts off with a main menu. Then when i press enter, its starts the loading screen. I have my manual state change using keypresses like so:
void Game::update()
{
static bool enterPreviouslyPressed = false;
static bool escapePreviousPressed = false;
const Uint8 *keys = SDL_GetKeyboardState(NULL);
if (keys[::SDL_SCANCODE_ESCAPE] && !escapePreviousPressed && typeid(*fsm->getState()) == typeid(GameState))
{
fsm->setState(menuState);
}
else if (keys[::SDL_SCANCODE_RETURN] && !enterPreviouslyPressed && typeid(*fsm->getState()) == typeid(MainMenuState))
{
fsm->setState(loadingState);
}
else if ((keys[::SDL_SCANCODE_RETURN] && !enterPreviouslyPressed) && typeid(*fsm->getState()) == typeid(LoadScreenState))
{
fsm->setState(gameState);
}
else if (keys[::SDL_SCANCODE_ESCAPE] && !escapePreviousPressed && typeid(*fsm->getState()) == typeid(MainMenuState))
{
exit(0);
}
enterPreviouslyPressed = keys[::SDL_SCANCODE_RETURN] != 0;
escapePreviousPressed = keys[::SDL_SCANCODE_ESCAPE] != 0;
fsm->update();
}
I did this to initially does this so i could change states manually to check that everything works. I was wondering if there was an easy(ish) way, like boolean flags for example or another simpler way to do this. I wasn't able find any tutorials online so wondering if someone knows the best solution as to how to do this. I did see a question on here, kindda similar but I wasn't sure if it answered my question as the person did this in threads which I am not familiar with how to implement. Apologies if I dont seem to have the logic correct - so please advise otherwise.
Looks fairly standard, except I would simplify it by keeping two keyboard state variables declared as class variables, like:
const Uint8 *curKeys = SDL_GetKeyboardState(NULL), *prevKeys;
// ...
void Game::update() {
prevKeys = curKeys;
curKeys = = SDL_GetKeyboardState(NULL);
//and so then compare curKeys to prevkeys
//and ditch the booleans
// ...
}
I'm making a thread software with VTK, where I need to change the model itself in real time, while I need to change his method of rendering. Everything is working fine, but, the problem start with the interactor->start(); , the model data gets updated just fine, but it's only showed on screen when I move The camera. Also I have selected some methods for generating a 3D data from a imagedata file, for that I need to close the vtk window (interactor window) and then the code will reopen it and send the new data generated to it...
I would need something like these:
int force close_window = false; int refresh_interactor = false;
I managed to make the Window close, but only with vtkcommand::Keypressed command, but idk how do I do with a new command :S, I tried the vtkcommand::UserEvent but I didn't found a good information about how to deal with that data (like some way to call it)
the way I'm dealing with VTK is with two threads, the first one, is just about the vtk iren loop, and the second one would manage the models and check if iren requires to be updated.
In my dream code it should be something like this:
=======================================================
bool VTKWindow()
{
...
vtkSmartPointer ator = vtkSmartPointer::New();
iren = vtkSmartPointer::New();
RenWindow = vtkSmartPointer::New();
render->SetBackground(.1, .2, .3);
RenWindow->AddRenderer(renderer);
iren->SetRenderWindow(RenWindow);
if(data_type == voxel_type)
{
Render->AddViewProp(VoxelData);
}
else
{
actor->SetMapper(PolyData);
Render->AddActor(Actor);
}
RenWindow->Render();
iren->Start();
}
void ManageVTK()
{
while true loop...
if(force close_window == true)
do some command to exit the iren loop
if(refresh_interactor == true)
do some command to refresh iren
}
Sorry for the english, it's not my native language, and also sorry about the question format, it's the first time I'm using stackoverflow
It may sounds stupid, but, I found a kind of solution for the problem.
I saw on related links this guy vtkRenderWindowInteractor event loop and threading and, it's almost the same problem...
class VTKNewEvent : public vtkCommand{
public:
vtkTypeMacro(VTKNewEvent , vtkCommand);
static VTKNewEvent * New(){
return new VTKNewEvent ;
}
void Execute(vtkObject * caller, unsigned long vtkNotUsed(eventId), void * vtkNotUsed(callData)){
vtkRenderWindowInteractor *iren = static_cast<vtkRenderWindowInteractor*>(caller);
if (iren_close == true){
iren->GetRenderWindow()->Finalize // Stop the interactor
iren->TerminateApp();
iren_close = false;
}
if (iren_update== true){
renderJanela->Render();
iren_update= false;
}
}
};
bool VTKWindow(){
vtkSmartPointer<VTKNewEvent > IrenRefresh= vtkSmartPointer<VTKNewEvent>::New();
...
iren->CreateRepeatingTimer(1);//this makes that IrenRefresh will be called at every 1ms
iren->AddObserver(vtkCommand::TimerEvent, IrenRefresh);
iren->Start();
...
}
it's simple, but, maybe not the best, but it did Th job, I hope this link will help people that are starting into the VTK world, since threads + rendering loop wasn't a simple job to understand what was going on