Hi again,
i have a new problem to solve concerning my little car game. Actually i
thought i did it but i just stopped a bug in my code.
In fact, i decided to not move the car but to scroll the screen. I only move
the car when the player reach one of the four edges of the map. I keep the
'virtual' position of the car on the circuit and i use them to determinate
how i need to stop scrolling the screen and start moving the car.
Here is the code :
def update(self):
> """
> Called every frames, update car's state.
> """
>
> self.rect = self.image.get_rect(center = (self.x,
> self.y))
>
>
> #x and y components
>
>
> speedx = math.sin(self.angle * (math.pi/180)) *
> self.speed
>
> speedy = math.cos(self.angle * (math.pi/180)) * self.speed
> *
> -1
>
>
> #update the virtual positions
>
>
> self.virtual_x +=
> speedx
>
> self.virtual_y +=
> speedy
>
>
> #check if the car is not out of the scrolling space on X
> if self.virtual_x < MAP_SIZE_X - SCREEN_SIZE_X/2 and
> self.virtual_x > SCREEN_SIZE_X/2:
> self.offset_x += speedx #move the screen
>
> else:
> self.x += speedx #move the car
>
> #do the same for Y
> if self.virtual_y < MAP_SIZE_Y - SCREEN_SIZE_Y/2 and
> self.virtual_y > SCREEN_SIZE_Y/2:
> self.offset_y += speedy
>
> else:
> self.y += speedy
>
> self.image = pygame.transform.rotate(self.original,
> self.angle * -1)
>
And i use self.offset_x and self.offset_y with the area parameters of the
blit function to blit my circuit :
screen.blit(circuit, (0, 0), area = (self.offset_x, self.offset_y,
> SCREEN_SIZE_X, SCREEN_SIZE_y))
However, i noticed than i should consider the fact than my car move 'speedx'
and 'speedy' pixels each frames. So actually, when i reach the left side of
the circuit (for example), the self.offset_x value is never 0 and always
increase each time the scrolling stop. I think to that since hours and i
still don't find solutions...
I thought to do something like :
#check if the car is not out of the scrolling space on X
> if self.virtual_x < MAP_SIZE_X - SCREEN_SIZE_X/2 and
> self.virtual_x > SCREEN_SIZE_X/2:
> self.offset_x += speedx #move the screen
>
> else:
> if self.virtual_x < SCREEN_SIZE_X/2:
> self.offset_x = 0
>
> if self.virtual_x > MAP_SIZE_X - SCREEN_SIZE_X/2:
> self.offset_x = MAP_SIZE_X - SCREEN_SIZE_X
>
> self.x += speedx #move the car
>
But i'm not sure i'm doing well since after playing sometimes i feel the car
virtual position no more match with the screen position.
I'm a bit lost and if anyone know what i'm doing wrong or if someone know a
better way to implement scrolling in car game, i would be happy to hear that
:)
Thanks for reading me.
PS : here is a code of a little application i use for testing scrolling
method : http://pastebin.com/deMv0TpB
