Collision

Player Hit-box In the last tutorials we created a hit-box for our saw and our spike. However, we have yet to create one for our player. Since our player jumps and slides this will make things a bit more difficult.

We will need to modify the player draw() method to add hit-boxes:

class player():
    ...    
    def draw(self, win):     
        if self.jumping:
            self.y -= self.jumpList[self.jumpCount] * 1.3
            win.blit(self.jump[self.jumpCount//18], (self.x,self.y))
            self.jumpCount += 1
            if self.jumpCount > 108:
                self.jumpCount = 0
                self.jumping = False
                self.runCount = 0
            self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10) # NEW
        elif self.sliding or self.slideUp:
            if self.slideCount < 20:
                self.y += 1
                self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10) # NEW
            elif self.slideCount == 80:
                self.y -= 19
                self.sliding = False
                self.slideUp = True
            # NEW ELIF STATEMENT
            elif self.slideCount > 20 and self.slideCount < 80: # NEW
                self.hitbox = (self.x,self.y+3,self.width-8,self.height-35) # NEW
                
            if self.slideCount >= 110:
                self.slideCount = 0
                self.runCount = 0
                self.slideUp = False
                self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10) # NEW
            win.blit(self.slide[self.slideCount//10], (self.x,self.y))
            self.slideCount += 1
            
        else:
            if self.runCount > 42:
                self.runCount = 0
            win.blit(self.run[self.runCount//6], (self.x,self.y))
            self.runCount += 1
            self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-13) # NEW
 
        pygame.draw.rect(win, (255,0,0),self.hitbox, 2) # NEW - Draws hitbox

Player Falling

When the player collides with an object we want it to appear as though they are falling. To do this we need to again modify the player class. We will add a falling attribute and add a check in our draw method so that we can draw a different image if the player is falling.

class player(object):
    run = [pygame.image.load(os.path.join('images', str(x) + '.png')) for x in range(8,16)]
    jump = [pygame.image.load(os.path.join('images', str(x) + '.png')) for x in range(1,8)]
    slide = [pygame.image.load(os.path.join('images', 'S1.png')),pygame.image.load(os.path.join('images', 'S2.png')),pygame.image.load(os.path.join('images', 'S2.png')),pygame.image.load(os.path.join('images', 'S2.png')), pygame.image.load(os.path.join('images', 'S2.png')),pygame.image.load(os.path.join('images', 'S2.png')), pygame.image.load(os.path.join('images', 'S2.png')), pygame.image.load(os.path.join('images', 'S2.png')), pygame.image.load(os.path.join('images', 'S3.png')), pygame.image.load(os.path.join('images', 'S4.png')), pygame.image.load(os.path.join('images', 'S5.png'))]
    fall = pygame.image.load(os.path.join('images','0.png')) # NEW
    jumpList = [1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-3,-3,-3,-3,-3,-3,-3,-3,-3,-3,-3,-3,-4,-4,-4,-4,-4,-4,-4,-4,-4,-4,-4,-4]
    def __init__(self, x, y, width, height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.jumping = False
        self.sliding = False
        self.falling = False # NEW
        self.slideCount = 0
        self.jumpCount = 0
        self.runCount = 0
        self.slideUp = False

    def draw(self, win):
        if self.falling: # NEW
            win.blit(self.fall, (self.x, self.y + 30)) # NEW
                
        elif self.jumping:
            self.y -= self.jumpList[self.jumpCount] * 1.3
            win.blit(self.jump[self.jumpCount//18], (self.x,self.y))
            self.jumpCount += 1
            if self.jumpCount > 108:
                self.jumpCount = 0
                self.jumping = False
                self.runCount = 0
            self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10)
        elif self.sliding or self.slideUp:
            if self.slideCount < 20:
                self.y += 1
                self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10)
            elif self.slideCount == 80:
                self.y -= 19
                self.sliding = False
                self.slideUp = True
            elif self.slideCount > 20 and self.slideCount < 80:
                self.hitbox = (self.x,self.y+3,self.width-8,self.height-35)
                
            if self.slideCount >= 110:
                self.slideCount = 0
                self.runCount = 0
                self.slideUp = False
                self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-10)
            win.blit(self.slide[self.slideCount//10], (self.x,self.y))
            self.slideCount += 1
            
        else:
            if self.runCount > 42:
                self.runCount = 0
            win.blit(self.run[self.runCount//6], (self.x,self.y))
            self.runCount += 1
            self.hitbox = (self.x+ 4,self.y,self.width-24,self.height-13)
 
        #pygame.draw.rect(win, (255,0,0),self.hitbox, 2)

Collision

Now that we have all of our hit-boxes setup we need to determine if objects have collided with one another. The first step to doing this is to add a method to both our saw and spike class called collide().

class saw:
    ...
    def collide(self, rect):
        if rect[0] + rect[2] > self.hitbox[0] and rect[0] < self.hitbox[0] + self.hitbox[2]:
            if rect[1] + rect[3] > self.hitbox[1]:
                return True
        return False

class spike(saw):
    ...
    def collide(self, rect):
        if rect[0] + rect[2] > self.hitbox[0] and rect[0] < self.hitbox[0] + self.hitbox[2]:
            if rect[1] < self.hitbox[3]:
                return True
        return False

Now that we have our collide methods completed we need to use them to check for collision with the player. We will do this from the game loop. Since we already have a for loop that moves each of our objects we will also check for collision in that loop.

if obstacle.collide(runner.hitbox):
    runner.falling = True

# This should go inside of the "for obstacle in obstacles" loop