Chuck's Academy

HTML5 Canvas

Adding a HUD and Scoreboard

In this chapter, we will learn how to implement a HUD (Heads-Up Display) in the canvas. A HUD is essential for displaying important information to the player, such as the score, level, and other game states. This allows players to understand their progress and the situation in the game at all times.

Displaying the Score on the Canvas

One of the most important parts of a HUD is the scoreboard or score. This allows the player to see their progress or performance. We will use the fillText function to draw the score on the canvas.

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"In this example, we create a drawScore function that uses fillText to display the score in the top-left corner of the canvas. In the draw function, we call drawScore each time the canvas is updated, ensuring that the score is visible and updated at all times."

Adding a Timer to the HUD

We can add a timer to the HUD to display the elapsed game time or set a time limit. For this, we use setInterval to update the time and fillText to display it on the screen.

Example: Upward Count Timer

This example shows how to create a timer that counts time in seconds from the start of the game.

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"In this code, we use setInterval to increment the time by one every second, simulating a timer. In the drawTimer function, we display the accumulated time on the screen. We call drawTimer within the main draw function so that the timer is always visible on the HUD."

Displaying a Game State

In addition to scores and time, we can display the game state on the HUD, such as 'Playing', 'Paused', or 'Game Over'. This information is useful for the player to understand the game phase they are in.

Example: State Message

We can use a variable to define the current game state and display this state on the screen.

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"In this example, we create a gameState variable to store the current game state, such as 'Playing', 'Paused', or 'Game Over'. The drawGameState function displays this state in the top-right corner of the canvas. We change the value of gameState in the pauseGame and endGame functions, according to the game conditions."

Exercise: Completing the HUD

To practice, try combining all the HUD elements into a complete interface that includes score, timer, and game state. You can also add a lives counter or any other informative element to enrich the HUD.

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"Here, we combine all the HUD elements into a single drawHUD function that displays the score, time, and game state. We call drawHUD within the main draw function to keep the HUD updated on the canvas."

Conclusion

In this chapter, we have learned to create a HUD to display key game information on the canvas. The HUD enhances the player's experience by keeping them informed about their progress and game status.


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