CODEWITHSUNDEEP
pythoneventspygamemask
Djanito
Djanito

Reputation: 197

Detect mouse event on masked image pygame

I create a clicker game and I have a transparent image (that I set in Mask for Pixel Perfect Collision ) but when I also click on the transparent part, the MOUSEBUTTONDOWN event is detected.

Actually, my code in the Player Class is:

self.image = pygame.image.load(str(level) + ".png").convert_alpha()
self.mask = pygame.mask.from_surface(self.image)
self.image_rect = self.image.get_rect(center=(WW, HH))

and this, in the main loop:

x, y = event.pos
if my_player.image_rect.collidepoint(x, y):
    my_player.click()

So I would like the click event to be triggered only when I click on the colored part of the image and not on the transparent background.

Thanks,

Upvotes: 3

Views: 1752

Answers (1)

sloth
sloth

Reputation: 101052

In addition to my_player.image_rect.collidepoint(x, y), check also for Mask.get_at:

get_at()

Returns nonzero if the bit at (x,y) is set.
get_at((x,y)) -> int

Note that you have to translate the global mouse position to the position on the mask.

Here's a runnable example:

import pygame

pygame.init()
screen = pygame.display.set_mode((800, 600))
class Cat:
    def __init__(self):
        self.image = pygame.image.load('cat.png').convert_alpha()
        self.image = pygame.transform.scale(self.image, (300, 200))
        self.rect = self.image.get_rect(center=(400, 300))
        self.mask = pygame.mask.from_surface(self.image)
running = True
cat = Cat()
while running:
    for e in pygame.event.get():
        if e.type == pygame.QUIT:
            running = False

    pos = pygame.mouse.get_pos()
    pos_in_mask = pos[0] - cat.rect.x, pos[1] - cat.rect.y
    touching = cat.rect.collidepoint(*pos) and cat.mask.get_at(pos_in_mask)

    screen.fill(pygame.Color('red') if touching else pygame.Color('green'))
    screen.blit(cat.image, cat.rect)
    pygame.display.update()

enter image description here

Also, self.image_rect should be named self.rect by convention. It's not absolutly necessary; but it's still a good idea and enables you to work with pygame's Sprite class (not shown in the example).

Upvotes: 7

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