I am pasting the code of the complete program of around 145 lines below
with the part that works correctly and the part that doesn't marked.
Why does the object NOT move in a circle when implemented as a class?
import sys, os, pygame, itertools
from math import sin,cos,pi, radians
from pygame.locals import *
os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (50,50) #Set window position
pygame.init()
clock = pygame.time.Clock()
FPS = 1000
SCREENW = 800 #screen width
SCREENH = 740 #screen height
BLACK = (0, 0, 0)
BLUE = (0, 0, 255)
ORANGE = (128, 100, 30)
FONT1= "Cookie-Regular.ttf"
SCREEN = pygame.display.set_mode((SCREENW, SCREENH), 0, 32) #display screen
clock = pygame.time.Clock()
#-------------------------------------------------------------------------------
def maketext(msg,fontsize, colour = ORANGE, font = FONT1):
mafont = pygame.font.Font(font, fontsize)
matext = mafont.render(msg, True, colour)
matext = matext.convert_alpha()
return matext
#-------------------------------------------------------------------------------
def print_info():
""""""
textcos = maketext(str(round(obj.rect.x, 2)) + " " +
str(round(obj.rect.y, 2)), 30)
SCREEN.blit(textcos, (obj.rect.x, obj.rect.y + 30))
#-------------------------------------------------------------------------------
class object_factory(pygame.sprite.Sprite):
def __init__(self, imagelist, xpos, ypos):
"""Constructor"""
pygame.sprite.Sprite.__init__(self)
self.name = ""
self.frame = 0
self.imagelist = imagelist
self.image = imagelist[self.frame]
self.mask = pygame.mask.from_surface(self.image) # pixelmask
self.rect = self.image.get_rect()
self.rect.x = xpos
self.rect.y = ypos
self.timer = 0
self.timerlimit = 10
#----------------------------------------------------------------------
#def move(self): # wallsprites, Herosprite, looptime
#self.rect.x += self.speedx
#self.rect.y += self.speedy
#----------------------------------------------------------------------
def update(self):
""""""
self.image = self.imagelist[self.frame]
if self.timer >= self.timerlimit:
self.frame += 1
if self.frame >= len(self.imagelist):
self.frame = 0
self.timer = 0
self.timer += 1
plat = pygame.image.load("plt0.png").convert_alpha()
star = pygame.image.load("gemp0.png").convert_alpha()
## declare the sprite group
platforms = pygame.sprite.Group()
boxes = pygame.sprite.Group()
rotcenx = SCREENW/2
rotceny = SCREENH/2
radius = 200
angle = radians(90) #pi/4 # starting angle 45 degrees
omega = radians(5) #Angular velocity
m = rotcenx + radius * cos(angle) #Starting position x
n = rotceny - radius * sin(angle) #Starting position y
for _ in itertools.repeat(None, 1):
midx = SCREENW/2
midy = SCREENH/2
radius1 = 200
angle1 = radians(180) #pi/4 # starting angle 45 degrees
angular_v = radians(5) #Angular velocity
a = midx + (radius1 * cos(angle1)) #Starting position x
b = midy - (radius1 * sin(angle1)) #Startinh position y
plat = object_factory([plat], a, b)
plat.radius = radius1
plat.angle = angle1
plat.angular_vel = angular_v
platforms.add(plat)
while True:
ms = clock.tick(FPS) # milliseconds passed since last frame
SCREEN.fill((BLACK))
## THIS CODE WORKS MOVES THE OBJECT IN A CIRCLE
SCREEN.blit(star, (m, n)) # Draw current x,y
angle = angle + omega # New angle, we add angular velocity
m = m + radius * omega * cos(angle + pi / 2) # New x
n = n - radius * omega * sin(angle + pi / 2) # New y
##---------------------------------------------------------------
# show object anchored to center of rotation
pygame.draw.line(SCREEN, ORANGE, (rotcenx, rotceny), (m, n))
text = maketext(str(radius), 30)
SCREEN.blit(text, (m, n - 40))
text = maketext((str(round(m, 2)) + " " + str(round(n, 2))), 30)
SCREEN.blit(text, (m, n + 40)) # Draw current x,y
## THIS CODE DOES NOT MOVE THE OBJECT IN A CIRCLE
for plat in platforms:
plat.angle = plat.angle + plat.angular_vel
plat.rect.x = plat.rect.x + plat.radius * plat.angular_vel *
cos(plat.angle + pi / 2)
plat.rect.y = plat.rect.y - plat.radius * plat.angular_vel *
sin(plat.angle + pi / 2)
##------------------------------------------------------------------------
pygame.draw.line(SCREEN, ORANGE, (midx, midy), (plat.rect.x,
plat.rect.y))
pygame.draw.circle(SCREEN, BLUE, (rotcenx, rotceny), radius1, 2)
platforms.update()
platforms.draw(SCREEN)
pygame.event.pump()
keys = pygame.key.get_pressed()
for event in pygame.event.get():
if event.type == QUIT or (event.type == KEYDOWN and event.key ==
K_ESCAPE):
pygame.quit()
sys.exit()
pygame.display.update()
pygame.time.wait(100)
On Tue, Apr 28, 2015 at 6:22 PM, diliup gabadamudalige <[email protected]>
wrote:
> Looking at the code on this page lines 47 & 48
>
>
> http://programarcadegames.com/python_examples/show_file.php?file=sprite_circle_movement.py
>
> is there a way to do
> self.rect.x +*= some value*
> self.rect.y += some value
>
> rather than
>
> self.rect.x = self.radius * math.sin(self.angle) + self.center_x
> self.rect.y = self.radius * math.cos(self.angle) + self.center_y
>
> ?
>
> I tired it in the code attached and strangely it works ok but only OUTSIDE
> THE class. When I implement the exact code in a class it does something
> weird. I can't find where I have gone wrong.
>
> Please help.
>
> Many thanks in advance.
>
> Diliup Gabadamudalige
>
>
>
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--
Diliup Gabadamudalige
http://www.diliupg.com
http://soft.diliupg.com/
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and all copies from your system and notify the sender immediately by return
e-mail. Any unauthorized reading, reproducing, printing or further
dissemination of this e-mail or its contents is strictly prohibited and may
be unlawful. Internet communications cannot be guaranteed to be timely,
secure, error or virus-free. The sender does not accept liability for any
errors or omissions.
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