Creating an Inventory Display System in Pygame for a Stardew Valley-Style Game

In this guide, we'll implement an inventory overlay that displays the player's current selected tool and seed at the bottom of the game screen, similar to the inventory system in Stardew Valley.

Implementation Approach

First, we'll create a new file named inventory_display.py that will contain an InventoryDisplay class. This class will be responsible for loading all possible tool and seed graphics and displaying the currently selected items on the screen.

Code Implementation

Let's start by creating the inventory_display.py file with the following content:

import pygame
from game_settings import *

class InventoryDisplay:
    def __init__(self, player):
        # Get the game display surface
        self.screen = pygame.display.get_surface()
        
        # Store reference to player object
        self.player = player
        
        # Dictionary to store tool graphics
        self.tool_graphics = {}
        
        # Dictionary to store seed graphics
        self.seed_graphics = {}
        
        # Path to overlay graphics
        graphics_path = '../assets/inventory/'
        
        # Load all tool graphics
        for tool in player.available_tools:
            # Load and convert the image
            tool_image = pygame.image.load(graphics_path + tool + '.png').convert_alpha()
            self.tool_graphics[tool] = tool_image
            
        # Load all seed graphics
        for seed in player.available_seeds:
            # Load and convert the image
            seed_image = pygame.image.load(graphics_path + seed + '.png').convert_alpha()
            self.seed_graphics[seed] = seed_image
    
    def render(self):
        # Get the currently selected tool's image
        current_tool = self.tool_graphics[self.player.active_tool]
        
        # Set position for tool display (bottom center)
        tool_position = current_tool.get_rect(midbottom=INVENTORY_POSITIONS['tool'])
        
        # Draw the tool on screen
        self.screen.blit(current_tool, tool_position)
        
        # Get the currently selected seed's image
        current_seed = self.seed_graphics[self.player.active_seed]
        
        # Set position for seed display (bottom center)
        seed_position = current_seed.get_rect(midbottom=INVENTORY_POSITIONS['seed'])
        
        # Draw the seed on screen
        self.screen.blit(current_seed, seed_position)

The key new method here is screen.blit(), which is used to draw images onto the screen at specified positions. It takes two parameters: the image to draw and the position coordinates. For example, self.screen.blit(image, (0, 0)) would draw the image at the top-left corner of the screen.

Next, we need to modify the game_level.py file to integrate this inventory display system:

import pygame
from game_settings import *
from player import Player
from inventory_display import InventoryDisplay

class GameLevel:
    def __init__(self):
        # Get the game display surface (same as in main.py)
        self.screen = pygame.display.get_surface()
        
        # Create sprite group
        self.all_sprites = pygame.sprite.Group()
        
        # Initialize game elements
        self.setup()
        
        # Create inventory display instance
        self.inventory_display = InventoryDisplay(self.player)
    
    def setup(self):
        # Create player instance
        self.player = Player((640, 360), self.all_sprites)
    
    def update(self, time_delta):
        # Clear screen with black background
        self.screen.fill('black')
        
        # Draw all sprites
        self.all_sprites.draw(self.screen)
        
        # Update all sprites
        self.all_sprites.update(time_delta)
        
        # Render inventory display
        self.inventory_display.render()

The changes involve importing the InventoryDisplay class, creating an instence of it after the player is set up, and calling its render() method in the update loop. Since the inventory needs to be drawn every frame, it's included in the update function.