Pygame Lua Integration: Simplifying Game Development

pygame-lua-bindings attempts to map the most useful pygame functions in lua. Houses a neat system for Streamlined access to the pygame mainloop and events. The following demo gives an example on how simple this is:

Demo

Lua (using pygame to lua bindings):

clear_canvas()
draw_text(50, 50, "Hello Pygame from lua!", "Arial", 30, 'red')

Compare to vanilla pygame:

import pygame
pygame.init()
screen = pygame.display.set_mode((800, 600))
font = pygame.font.SysFont('Arial', 30)
red = (124, 0, 0)
green = (0, 255, 0)
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    screen.fill((0, 0, 0))
    screen.blit(font.render('Hello Pygame from python!', True, red), (50, 50))
    pygame.display.flip()
pygame.quit()

More in depth examples can be found on the wiki.

Main loop handling from within lua

Assumes the use of high-level abstractions to register event handlers and inject control functions into the main loop. The following snake game provides a clear visualization of this process start to finish.

-- Game constants
local SCREEN_WIDTH, SCREEN_HEIGHT, TILE_SIZE = 800, 600, 20

-- Initialize game state
local snake = 
local food = {x = 15, y = 15}
local direction = {x = 1, y = 0}
local score = 0
local input_locked = false  -- Lock for input processing

-- Draw function
local function draw_game()
    clear_canvas()

    -- Draw snake
    for _, s in ipairs(snake) do
        draw_rectangle(s.x * TILE_SIZE, s.y * TILE_SIZE, TILE_SIZE, TILE_SIZE, "#00FF00")
    end

    -- Draw food
    draw_rectangle(food.x * TILE_SIZE, food.y * TILE_SIZE, TILE_SIZE, TILE_SIZE, "#FF0000")

    -- Draw score
    draw_text(10, SCREEN_HEIGHT - 30, "Score: " .. score, "Arial", 20, "#FFFFFF")

    flip_display()
end

-- Event handling
register_event_handler('on_keydown', function(event)
    if input_locked then return end  -- Ignore inputs if locked
    local key_map = {
        [K_RIGHT] = {1, 0},   -- Right arrow
        [K_LEFT] = {-1, 0},  -- Left arrow
        [K_UP] = {0, -1},  -- Up arrow
        [K_DOWN] = {0, 1}    -- Down arrow
    }
    local dir = key_map[event.key]
    if dir and (dir[1] ~= -direction.x and dir[2] ~= -direction.y) then
        direction = {x = dir[1], y = dir[2]}
        input_locked = true  -- Lock input until next update
    end
end)

-- Game logic
function process_events()
    for _, e in ipairs(get_events()) do
        if e.type == "QUIT" then
            stop_main_loop()
        end
    end
end

function update_position()
    -- Move snake
    local head = {x = snake[1].x + direction.x, y = snake[1].y + direction.y}

    -- Check collision with walls or self
    if head.x < 0 or head.x >= SCREEN_WIDTH / TILE_SIZE or
       head.y < 0 or head.y >= SCREEN_HEIGHT / TILE_SIZE or
       (#snake >= 4 and (function()
            for _, s in ipairs(snake) do
                if s.x == head.x and s.y == head.y then
                    return true
                end
            end
            return false
       end)()) then
        stop_main_loop()
    end

    -- Move snake
    table.insert(snake, 1, head)

    -- Check for food collision
    if head.x == food.x and head.y == food.y then
        score = score + 1
        food = {x = math.random(0, SCREEN_WIDTH / TILE_SIZE - 1), y = math.random(0, SCREEN_HEIGHT / TILE_SIZE - 1)}
    else
        table.remove(snake)
    end

    input_locked = false  -- Unlock input after updating
end

-- Register functions and start the loop
register_function("process_events", process_events)
register_function("update_position", update_position)
register_function("draw", draw_game)
start_main_loop()

Bound methods

All bound methods and their usage can be found on the wiki page. This project is just for fun, not to re-invent the wheel.

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