Scrolling Background Explanation

Overview

In sprint 2 we decided to design the game background and finish the implementation according to the Gamestory. Current background image is here.

Code implementation

BackgroundRenderComponent

Under the com/deco2800/game/rendering package. We created a new BackgroundRenderComponent.java class. The aim of creating this class is to create an object which can render the background image texture.

1. The texture path is required in the constructor. This will be efficient for adding different background images(p.s. could be helpful in multiple maps)

    public BackgroundRenderComponent(String texturePath) {
        this.texturePath = texturePath;
    }

2.Considering that the background image needs to be rendered repeatedly during the game. We came out with the solution by creating a global variable private float horizontaland set it default to zero. Then create a public function to allow changing the horizontal variable manually.

    /**
     * Set the horizontal start point for the background texture
     * @param x horizontal value
     */
    public void setHorizontal(float x) {
        horizontal = x;
    }

Then, override the following function so that the background image can be drew from different horizontal start point.

    @Override
    public void draw(SpriteBatch batch) {
        batch.draw(texture, -30, 0, 30, 15);
        batch.draw(texture, horizontal, 0, 30, 15);
    }

3.Under com/deco2800/game/areas/ForestGameArea.java, two core functions have been added. The showBackground() can be called to render the background from the beginning.

    private void showBackground() {
        Entity gameBg = new Entity();
        gameBg.addComponent(new BackgroundRenderComponent("images/background.png"));
        spawnEntity(gameBg);
    }

And the showScrollingBackground(int counter) need to be passed into a count number, which will render the background again and again.

    public void showScrollingBackground(int counter) {
        Entity gameBg = new Entity();
        BackgroundRenderComponent newBg = new BackgroundRenderComponent("images/background.png");
        newBg.setHorizontal(30f * counter);
        gameBg.addComponent(newBg);
        spawnEntity(gameBg);
    }

4.Under the render() function in com/deco2800/game/screens/MainGameScreen.java, the background will be rendered repeatedly until the loop terminate.

    ...
    // infinite loop for terrain and obstacles
    if(screenVector.x > (2*counter+1)*10) {
      counter+=1;
      forestGameArea.showScrollingBackground(counter);
    ...