turret.py

import math
import pygame
import sys

pygame.init()

screen = pygame.display.set_mode((800,400))
pygame.display.set_caption('Game Title')

clock = pygame.time.Clock()
angle=0
turretLen = 75
moveAmt = 0
x1=100
y1=100

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    keys = pygame.key.get_pressed()

    if keys[pygame.K_LEFT]:
        angle -= 5
    if keys[pygame.K_RIGHT]:
        angle += 5
    print(angle)
    if keys[pygame.K_UP]:
        moveAmt += 1
    if keys[pygame.K_DOWN]:
        moveAmt -= 1
        if moveAmt <= 0:
            moveAmt = 0

    moveAmt = moveAmt*.95

    x1 += math.cos(math.radians(angle))*moveAmt
    y1 += math.sin(math.radians(angle))*moveAmt

    x2 = math.cos(math.radians(angle))*turretLen
    y2 = math.sin(math.radians(angle))*turretLen

    screen.fill((70,70,70))

    pygame.draw.circle(screen, 'red', (x1,y1), 50, 1)
    pygame.draw.line(screen, 'blue', (x1,y1), (x1+x2,y1+y2), 3)

    pygame.display.update()     ## vs. flip()
    clock.tick(60)