CODEWITHSUNDEEP
pythonpygameshapely
Arda Yılmaz
Arda Yılmaz

Reputation: 159

Pygame rotated rect problems

I have a problem about rotated rect collision.

Here is my Car class:

class Car:
def __init__(self,x,y):
    self.x = x
    self.y = y
    self.default_image = pygame.image.load("car.png")
    self.image = self.default_image
    self.w = self.image.get_size()[0]
    self.h = self.image.get_size()[1]
    self.right_image = pygame.transform.rotate(self.default_image, -10)
    self.left_image = pygame.transform.rotate(self.default_image, 10)
    self.rot = 0
def render(self):
    screen.blit(self.image,self.getRect())
def getRect(self):
    return self.default_image.get_rect(center=(self.x,self.y))
def getMask(self):
    return Polygon(calculate(self.getRect(),self.rot))
def right(self):
    self.rot = -10
    self.image = self.right_image
def left(self):
    self.rot = 10
    self.image = self.left_image
def default(self):
    self.rot = 0
    self.image = self.default_image
def drawHitbox(self):
    pygame.draw.lines(screen,(242, 236, 12),True,calculate(self.getRect(),self.rot),1)

Here is my 'calculate' function:

def calculate(irect,angle):
    pivot = math.Vector2(irect[0],irect[1])
    p0 = (math.Vector2(irect.topleft) - pivot).rotate(-angle) + pivot 
    p1= (math.Vector2(irect.topright) - pivot).rotate(-angle) + pivot 
    p2 = (math.Vector2(irect.bottomright) - pivot).rotate(-angle) + pivot 
    p3 = (math.Vector2(irect.bottomleft) - pivot).rotate(-angle) + pivot
    return [p0,p1,p2,p3]

Here is my code to check collison:

for i in vehicles:
        i.render()
        if i.getMask().intersects(car.getMask()):
            death = True

I made a function to draw hitbox of car. But car and hitbox are different when angle of car isn't 0.

enter image description here enter image description here enter image description here

I am using shapely polygon to make rotated rects.

My english isn't very well, I tried to tell you as much as I could.

Upvotes: 1

Views: 99

Answers (1)

Rabbid76
Rabbid76

Reputation: 210968

The image is rotated around it's center. You'll also need to rotate the rectangle around its center Therefore, the pivot point needs to be the center of the rectangle, not its top left point:

pivot = math.Vector2(irect[0],irect[1])

pivot = math.Vector2(irect.center)

calculate function:

def calculate(irect,angle):
    pivot = math.Vector2(irect.center)
    p0 = (math.Vector2(irect.topleft) - pivot).rotate(-angle) + pivot 
    p1= (math.Vector2(irect.topright) - pivot).rotate(-angle) + pivot 
    p2 = (math.Vector2(irect.bottomright) - pivot).rotate(-angle) + pivot 
    p3 = (math.Vector2(irect.bottomleft) - pivot).rotate(-angle) + pivot
    return [p0,p1,p2,p3]

Upvotes: 2

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