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SFML Pong Help

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Started by SoulHeart February 05, 2012 02:50 AM

4 comments, last by BeerNutts 12 years, 2 months ago

SoulHeart

101

Author

February 05, 2012 02:50 AM

I need some advice for a loop in my pong game.



#include "Play.h"

void Play::Show(sf::RenderWindow& window3)

{

    sf::Event GEvent;

    //load background image

    sf::Image image4;

    image4.LoadFromFile("PlayBack.jpg");

    //load grey bar

    sf::Image image5;

    image5.LoadFromFile("GreyBar.jpg");

    //setup grey bar

    sf::Sprite GBar(image5);

    GBar.Resize(800,50);

    //setup background image

    sf::Sprite PlayBack(image4);

    PlayBack.Resize(800,600);

    //load paddle

    sf::Image image6;

    image6.LoadFromFile("paddle.png");

    //setup paddle

    sf::Sprite ppaddle(image6);

    ppaddle.Rotate(90);

    //load ball

    sf::Image image7;

    image7.LoadFromFile("ball.png");

    //setup ball

    sf::Sprite ball(image7);

    ball.SetPosition(350, 300);

    while(window3.GetEvent(GEvent))

    {

	    int x = GEvent.MouseMove.Y;

		    if(x < 140)

		    {

			    x = 140;

		    }

		    if(GEvent.MouseMove.Y || GEvent.MouseMove.X)

		    {

			    ppaddle.SetPosition(15, x );

		    }

    }

    window3.Draw(PlayBack);

    window3.Draw(GBar);

    window3.Draw(ppaddle);

    window3.Draw(ball);

    window3.Display();

}

The Paddle moves fine, but if the cursor is in certain spots, the sprite will disappear idk why. Is that the right loop to update the game? Also, I need help with ball movement. I like to have the user click for the ball to start moving. I couldn't get the ball to move and I'm guessing i will need a different loop or maybe even a whole new function.Thanks for any advice you can give me.

Eridan

100

February 05, 2012 08:11 AM

I'm not sure exactly how your functions are defined, but It looks to me like the drawing functions should be inside the game loop. The way you have them, nothing will get drawn until the game is over.

I would try doing this:



    while(window3.GetEvent(GEvent))

    {

            int x = GEvent.MouseMove.Y;

                    if(x < 140)

                    {

                            x = 140;

                    }

                    if(GEvent.MouseMove.Y || GEvent.MouseMove.X)

                    {

                            ppaddle.SetPosition(15, x );

                    }

        window3.Draw(PlayBack);

        window3.Draw(GBar);

        window3.Draw(ppaddle);

        window3.Draw(ball);

        window3.Display();

    }

You can ignore me if ppaddle.SetPosition contains drawing functions, but I suspect it doesn't. I'm not sure what your other issue is, but this change should help get things moving. I'll edit this if I see anything else.

BeerNutts

4,410

February 05, 2012 05:54 PM

I'm not sure exactly how your functions are defined, but It looks to me like the drawing functions should be inside the game loop. The way you have them, nothing will get drawn until the game is over.

I would try doing this:
...

You can ignore me if ppaddle.SetPosition contains drawing functions, but I suspect it doesn't. I'm not sure what your other issue is, but this change should help get things moving. I'll edit this if I see anything else.

Eridan, that's not correct. That while loops will exit when there's not any input to be read. it doesn't draw when game over. And, this Show function isn't the main game loop.

Soulheart, ignore what Eridan said. Here are a few suggestions I have for you.

#1, you should not be loading the image every time you call show. SFML image loading should be done once per image. So, you should load the image, then assign the Sprite. You can have the Sprites as member variable, or pass them in the function, or have them grouped in their own class and pass in the class.

#2, You're Show should be separate from checking User input. So, you should check user input, and adjust the location of your paddle, and then, in a different function, draw the images. By having the sprites defined outside these functions, they can be updated in different functions.

As for the cursor, I'm not exactly sure what the deal is with that.

If you want the game to start with a click, then, you could have different States. So, you have a WAITING_FOR_START state. In your CheckUserInput function, if you're in the WAITING_FOR_START state, and the user clicks the mouse, you shoot the ball out. You would then change the State to GAME_PLAYING. When the Game is over, you can change it to GAME_OVER, and in your CheckUserInput, you would ask if the user wants to play again. that's the general idea.

My Gamedev Journal: 2D Game Making, the Easy Way

---(Old Blog, still has good info): 2dGameMaking
-----
"No one ever posts on that message board; it's too crowded." - Yoga Berra (sorta)

SoulHeart

101

Author

February 05, 2012 09:04 PM

ok thanks. I'll see what I can work up

SoulHeart

101

Author

February 05, 2012 10:23 PM

So is this a good way to set up the game loop?

Main.cpp



//include....

//Make The game state

enum GameState



int main()

{

	//Load images, fonts, etc.....

	//Starts the Game

	Game::Start();

	//shouldn't get here but if it does return 0

	return 0;

}

Game.cpp



//include........

//Starts the game

void Start()

{

	//GState = anything but Uninitialized, return

	if(GState != Uninitialized)

		return;

	//Creates game window

	GameW.Create(sf::VideoMode(800, 600, 32),"Pang!", sf::Style::Fullscreen);

	//show Splashscreen

	GState = FirstState;

	//while the game isn't exiting run the game loop

	while(!IsExiting())

	{

		GameLoop();

	}

	GameW.Close();

}

//exiting loop

bool IsExiting()

{

	if(GState == Exiting)

		return true;

	else

		return false;

}

//Game loop

void GameLoop()

{

	//GState Switch

	switch(GState)

	{

		case //GState

		{

			//Run certain function

			break;

		}

	}

}

void Play()

{

//show/update the game

Show();

//get input and set changes(but not show them)

Input();  

}

Is this a good foundation?
Please help me out if it isn't.

BeerNutts

4,410

February 06, 2012 06:17 PM

It's a start. You'll want to call Input(), and then Show() somewhere within your Game Loop. You will probably want an Update(), which updates all the objects in your game.

So, basically, Input() get the input from the user, and applies the proper settings to the paddle (ie, if used is pressing LEFT, then the velocity of the Paddle is set to a negative X value).
Update updates the ball, and the paddles, based on the velocities, and if collision checks (ball hits paddle or off screen, or paddle hits edge of screen).

And, Show draws all the objects on the screen. All the State stuff can be handle multiple ways, just find one that you are comfortable with. I won't say what you've done is the best solution, but, it's a good start, and, as you go, you'll learn bettre ways of doing things.

My Gamedev Journal: 2D Game Making, the Easy Way

---(Old Blog, still has good info): 2dGameMaking
-----
"No one ever posts on that message board; it's too crowded." - Yoga Berra (sorta)

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