Howdy,
Put your background image in a sprite object and add a mask attribute, just
like you do for Blok objects.
Then test for collisions with pygame.sprite.collide_mask.
Gumm
On Mon, Dec 13, 2010 at 1:27 AM, Petrovski
<peter.b...@tweakedsolutions.nl>wrote:
> Hi,
>
> I´m having some trouble with detecting collisions between 2 masks.
>
> What i´m trying to do is create a sort of a terrain with a polygon,
> then drop a box that should keep dropping until it hits the "terrain".
>
> With the following code I get 2 masks that when checked with
> mask.count() are greater than 0.
>
> Problem is they are not detecting each other. I tried both
> pygame.mask.from_threshold and pygame.mask.from_surface to make a mask
> of the polygon. For overlapping detection I tried Mask.overlap_area
> and Mask.overlap. Both did not work.
>
> Any help would be greatly appreciated
>
> This is my code:
> +-------------------------Main class:
> import pygame
> import Blok
> from pygame.locals import *
>
> def main():
>
> pygame.init()
>
> screen = pygame.display.set_mode((750, 500))
> pygame.display.set_caption('Spike 2')
>
> #Backgrounds
> background2 = pygame.Surface(screen.get_size())
> background2 = background2.convert()
> background2.fill((0, 0, 250))
>
> background = pygame.Surface(screen.get_size())
> background = background.convert()
> background.fill((0, 0, 250))
> background.set_colorkey((0, 0, 250), RLEACCEL)
>
> #Make the terrain polygon
> area = [(0, 300), (290, 475), (450, 200), (550,475),(750,350),
> (750,500),(0,500)]
> colour = (250, 0, 0)
> pygame.draw.polygon(background, colour, area)
>
> clock = pygame.time.Clock()
> zoneObjectSprites = pygame.sprite.RenderPlain()
>
> while 1:
> clock.tick(60)
>
> for event in pygame.event.get():
> if event.type == QUIT:
> return
> elif event.type == KEYDOWN and event.key == K_ESCAPE:
> return
> if event.type == MOUSEBUTTONDOWN:
> if event.button == 3:
> #spawn a box at the cursor position
> mX, mY = pygame.mouse.get_pos()
> Blok.Blok(mX,mY).add(zoneObjectSprites)
>
> #Blue background and terrain
> screen.blit(background2, (0, 0))
> screen.blit(background, (0, 0))
>
> #Get the mask of the terrain
> #terrainmask = pygame.mask.from_threshold(background, colour,
> (1, 1, 1))
> terrainmask = pygame.mask.from_surface(background)
>
> #print the mask count to see if its big enough
> print terrainmask.count()
> for object in zoneObjectSprites:
> object.gravity(terrainmask)
> zoneObjectSprites.draw(screen)
> pygame.display.flip()
>
> #this calls the 'main' function when this script is executed
> if __name__ == '__main__': main()
>
>
> +-------------------------Blok class:
> class Blok(pygame.sprite.Sprite):
>
> def __init__(self, X, Y):
> pygame.sprite.Sprite.__init__(self)
> self.image, self.rect = load_image('blok1.bmp',-1)
> screen = pygame.display.get_surface()
> self.area = screen.get_rect()
> self.rect.center = X, Y
> self.gravityForce = 3
> self.mask = pygame.mask.from_surface(self.image,255)
> print self.mask.count()
>
> def gravity(self,terrainmask):
> dy = self.mask.overlap(terrainmask,(0,0))
> print dy
>
> #did we hit the ground?
> if dy is not None:
> print 'hit ground'
> else:
> newpos = self.rect.move((0, self.gravityForce))
> self.rect = newpos
>
> #kill object if it goes offscreen
> if self.rect.top > 500:
> self.kill()
>
