Resolve Pygame Object Duplication During Movement

Learn why your `Pygame` objects might be duplicating during movement and discover an effective solution to correct it.
---
This video is based on the question https://stackoverflow.com/q/74107941/ asked by the user 'Zero' ( https://stackoverflow.com/u/14914065/ ) and on the answer https://stackoverflow.com/a/74108097/ provided by the user 'svfat' ( https://stackoverflow.com/u/2419628/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Pygame movement causes the object to duplicate

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Fixing Object Duplication in Pygame: A Simple Guide

When diving into game development with Pygame, encountering issues is not uncommon. One such problem is when an object appears to duplicate instead of moving. If you're working with a simple movement script and notice that your block isn't moving as expected, this guide is for you! Let’s explore the issue and how to resolve it effectively.

The Problem: Object Duplication

In your Pygame project, you’ve created a block designed to move across the screen when specific keys are pressed. However, rather than moving smoothly, the block duplicates itself, causing visual confusion. Each time a movement key is pressed, a new block is drawn in the new location, while the old block remains, leading to a cluttered display of rectangles.

Your Code Overview

Here is a simplified look at the critical part of your original code, which causes the duplication issue:

[[See Video to Reveal this Text or Code Snippet]]

In this loop, pygame.draw.rect() is executed within the event loop without properly managing the previous rectangle's position, which results in multiple rectangles being drawn on the screen.

The Solution: Use a Single Rectangle Instance

To solve this duplication problem, you need to maintain a single instance of the rectangle and move it accordingly. Here’s how you can adjust your code:

Step-by-Step Code Correction

Define the Rectangle:
Create a rectangle using pygame.Rect(), and store it in a variable. This allows you to refer back to it later instead of creating a new rectangle each frame.

[[See Video to Reveal this Text or Code Snippet]]

Update Rectangle Position:
Instead of changing posx and posy, you will use the rectangle's built-in method move_ip() to update its position directly. This way, you will retain the rectangle instance while moving it.

[[See Video to Reveal this Text or Code Snippet]]

Draw the Rectangle:
Move the pygame.draw.rect() call outside the event loop, ensuring it only draws the rectangle once per frame.

[[See Video to Reveal this Text or Code Snippet]]

Complete Code Fix

With all the above changes, your corrected code block should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you've successfully corrected the duplication issue in your Pygame project. Remember, the key takeaway here is to manage your game objects effectively by reusing the same instance rather than creating multiple instances unnecessarily. This not only ensures cleaner visuals but also improves your game's performance. Happy coding!

Видео Resolve Pygame Object Duplication During Movement канала vlogize