Start Game Function –

This function will load up all of the default values for this game, lets take a closer look into what it does.

        private void StartGame()
        {
            // this is the start game function

            Canvas.SetLeft(background, 0); // set the first background to 0
            Canvas.SetLeft(background2, 1262); // set the second background to 1262

            // set the player x to 110 and y to 140
            Canvas.SetLeft(player, 110);
            Canvas.SetTop(player, 140);

            // set the obstacle x to 950 and y to 310
            Canvas.SetLeft(obstacle, 950);
            Canvas.SetTop(obstacle, 310);
            // set run sprite function to 1
            runSprite(1);

            // set the obstacle sprite, load the image from the images folder
            obstacleSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/obstacle.png"));
            obstacle.Fill = obstacleSprite; // assign the obstacle sprite to the obstacle object 

            // set jumping to false
            jumping = false;
            // set game over to false
            gameover = false;
            // set score to 0
            score = 0;
            // set the score text to the score integer
            scoreText.Content = "Score: " + score;

            // start the game timer
            gameTimer.Start();
        }

We start with positioning the background rectangles

Canvas.SetLeft(background, 0); // set the first background to 0

Canvas.SetLeft(background2, 1262); // set the second background to 1262

First we are setting the background LEFT or X position to 0. This is the first background rectangle

Background2 rectangles LEFT or X position is being set to 1262 so right behind the first background. 1262 is the width of the rectangles if you remember from the XAML code. Everything is related from XAML to C#.

Now we set the position of the player

// set the player x to 110 and y to 140

Canvas.SetLeft(player, 110);

Canvas.SetTop(player, 140);

Player left position is being set to 110 pixels

Player top position is being set to 140 pixels.

When the game runs, the player should drop down to the platform and start running.

Set the position for the obstacle rectangle

// set the obstacle x to 950 and y to 310

Canvas.SetLeft(obstacle, 950);

Canvas.SetTop(obstacle, 310);

Set the obstacle rectangles left position to 950 pixels so its off screen when the game starts

Set the obstacle rectangles top position to 310 pixels.

runSprite(1); this line is running the run sprite function with 1 meaning it will start the function and load the first frame of the running animation.

// set the obstacle sprite, load the image from the images folder

obstacleSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/obstacle.png"));

obstacle.Fill = obstacleSprite; // assign the obstacle sprite to the obstacle object

These two lines above is loading the obstacle.png file into the obstacle sprite image brush, and then we are linking the obstacle fill to the obstacle sprite.

// set jumping to false

jumping = false;

// set game over to false

gameover = false;

// set score to 0

score = 0;

// set the score text to the score integer

scoreText.Content = "Score: " + score;

jumping is set to false, game over is set to false because the game just started, score is set to 0 and score texts content is accessed to make sure we are updating it in the beginning of the game with a 0.

gameTimer.Start(); this line is starting the game timer.

Run Sprite Function

We are now in the run sprite function, this function will change the player image and show these sequence of images as a animation. Lets see how its done. The full run sprite function is below there are comment in the code feel free to take a look.

        private void runSprite(double i)
        {
            // this is the run sprite function, this function takes one argument inside its brackets
            // it takes a double variable called i
            // we will use this i to change the images for the player

            // below is the switch statement that will change the player sprite
            // when the i value changes between 1 and 8 it will assign appropriate sprite to the player sprite
            switch (i)
            {

                case 1:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_01.gif"));
                    break;
                case 2:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_02.gif"));
                    break;
                case 3:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_03.gif"));
                    break;
                case 4:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_04.gif"));
                    break;
                case 5:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_05.gif"));
                    break;
                case 6:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_05.gif"));
                    break;
                case 7:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_07.gif"));
                    break;
                case 8:
                    playerSprite.ImageSource = new BitmapImage(new Uri("pack://application:,,,/images/newRunner_08.gif"));
                    break;

            }
            // finally assign the player rectangle to the player sprite
            player.Fill = playerSprite;
        }

This function has one big switch statement inside of it. This switch statement changes the value of the player sprite image brush as the value of I changes. For example, let’s say we run this function and pass in 3

The switch statement will check if there is a case for 3 if so, we go and change the image source of the player sprite object to newRunner_03.gif. if this value was 4 it will get the newRunner_04.gif image and so on.

We are passing the double variable called I through this function and that’s was we are using to make sure we get the right image when its being displayed. End of each case we have a break; keyword. This keyword means if this case was found then we don’t need to check through rest of them we can break the operation here and return to normal the job is done. Out of the switch statement curly brackets we are stating player.Fill = playerSprite; this line as it was used for the background or the obstacle is simply loading the playerSprite texture from the image to the player rectangle fill colour. If your wondering how’s it going to animate like this then remember that spriteInt double variable we made earlier we will use that to pass the value in for I and then it will animate the player rectangle for us.

Go to Page 6 for Game engine event source code