Collision in pygame not working (objects collide but code not triggering)

Question

I'm making a Pygame program for a school project. The player character will pass through an enemy sprite without triggering the collision. How do I fix this?

CODE should be run if there is any overlap between the two sprites.

if CharY > thing_starty and CharY < thing_starty + Enemy2_height or CharY+PCHeight > thing_starty and CharY + PCHeight < thing_starty + Enemy2_height:
    if CharX > thing_startx and CharX < thing_startx + Enemy2_width or CharX + PCWidth > thing_startx and CharX + PCWidth < thing_startx + Enemy2_width:
        CODE

Have you tried to print out the values of your variables after each IF block is triggered? — alec_djinn, Jul 01 '19 at 13:15

score 1 · Answer 1 · edited Jul 01 '19 at 14:04

I recommend to use pygame.Rect objects and .colliderect() to check for the collision of two rectangles:

# detects collisions
charRect  = pg.Rect(CharX, CharX, PCWidth, PCHeight)
enemyRect = pg.Rect(thing_startx, thing_starty, Enemy2_width, Enemy2_height)
if charRect.colliderect(enemyRect):
    # [...]
    # CODE

If you want to do the collision detection yourself, then you've got to check if the rectangles are overlapping in both dimensions.

A range [x1, x1+w1] overlaps a range [x2, x2+w2] if the following condition is fulfilled:

intersect = x1 < x2+w2 and x2 < x1+w1

Note, w1 and w2 have to be greater than 0.

Do this for both dimensions:

if CharX < thing_startx + Enemy2_width  and thing_startx < CharX + PCWidht and \
   CharY < thing_starty + Enemy2_height and thing_starty < CharY + PCHeight
    # [...]
    # CODE

Collision in pygame not working (objects collide but code not triggering)

1 Answers1