Python: How to make drawn elements snap to grid in pygame

by

You have to align the position to the grids size. Use the floor division operator (//) to divide the coordinates by the size of a cell and compute the integral index in the grid:

x, y = pygame.mouse.get_pos()

ix = x // sizebtwn
iy = y // sizebtwn

Multiply the result by the size of a cell to compute the coordinate:

self.cx, self.cy = ix * sizebtwn, iy * sizebtwn

Minimal example:

import pygame
pygame.init()

screen = pygame.display.set_mode((200, 200))
clock = pygame.time.Clock()

def drawgrid(w, rows, surface):
    sizebtwn = w // rows 
    for i in range(0, w, sizebtwn):
        x, y = i, i
        pygame.draw.line(surface, (255, 255, 255), (x, 0), (x, w))
        pygame.draw.line(surface, (255, 255, 255), (0, y), (w, y))

class Cube:
    def update(self, sizebtwn):
        x, y = pygame.mouse.get_pos()
        ix = x // sizebtwn
        iy = y // sizebtwn
        self.cx, self.cy = ix * sizebtwn, iy * sizebtwn
        self.square = pygame.Rect(self.cx, self.cy, sizebtwn, sizebtwn)
    def draw(self, surface):
        click = pygame.mouse.get_pressed()
        if click[0]:
            pygame.draw.rect(surface, (255, 255, 255), self.square)

cube = Cube()

run = True
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    cube.update(screen.get_width() // 10)

    screen.fill(0)
    drawgrid(screen.get_width(), 10, screen)
    cube.draw(screen)
    pygame.display.flip()

More Related Contents:

  1. Pygame with Multiple Windows
  2. Why is nothing drawn in PyGame at all?
  3. Countdown timer in Pygame
  4. Pygame doesn’t let me use float for rect.move, but I need it
  5. How can i shoot a bullet with space bar?
  6. How to convert the background color of image to match the color of Pygame window?
  7. Is this bad programming practice in tkinter?
  8. Add pygame module in PyCharm IDE
  9. Running a process in pythonw with Popen without a console
  10. Why is my pygame display not responding while waiting for input?
  11. How can I crop an image with Pygame?
  12. Is it possible to change sprite colours in Pygame?
  13. How can I made a collision mask?
  14. How to simulate Jumping in Pygame for this particular code
  15. Difference between pygame.display.update and pygame.display.flip
  16. Pygame Tic Tak Toe Logic? How Would I Do It
  17. Program freezing during the execution of a function in Tkinter
  18. pygame platformer – How can I make the bottom solid?
  19. pygame sprite wall collision [duplicate]
  20. How do I scale a PyGame image (Surface) with respect to its center?
  21. How to easily print ascii-art text? [closed]
  22. Pygame: Draw single pixel
  23. How to draw images and sprites in pygame?
  24. How to install PyGame on Python?
  25. pygame audio playback speed
  26. In Pygame, normalizing game-speed across different fps values
  27. Pygame: Centering text system font text
  28. Converting .py to .ui file [duplicate]
  29. What is the difference between super() with arguments and without arguments?
  30. How do I change the volume of the sound or music in PyGame?

Leave a Comment