'how to control snake with only two keys i.e left and right
currently, i'm using all four keys to steer the snake left, right, up and down. I'm wondering how can i only use left and right key to move the snake around.
if event.key == pygame.K_LEFT:
snake.direction = 2
elif event.key == pygame.K_RIGHT:
snake.direction = 3
elif event.key == pygame.K_UP:
snake.direction = 0
elif event.key == pygame.K_DOWN:
snake.direction = 1
def move(self):
if self.direction is 0:
self.dy = -self.block
self.dx = 0
if self.direction is 1:
self.dy = self.block
self.dx = 0
if self.direction is 2:
self.dy = 0
self.dx = -self.block
if self.direction is 3:
self.dy = 0
self.dx = self.block
self.x += self.dx
self.y += self.dy
can anyone guide me how to do that?
Solution 1:[1]
Define the directions as follows:
- 0: move up
- 1: move right
- 2: move down
- 3: move right
def move(self):
if self.direction is 0:
self.dy = -self.block
self.dx = 0
if self.direction is 1:
self.dy = 0
self.dx = self.block
if self.direction is 2:
self.dy = 0
self.dx = -self.block
if self.direction is 3:
self.dy = self.block
self.dx = 0
self.x += self.dx
self.y += self.dy
When right is pressed then add 1 to snake.direction and when left is pressed the subtract 1. Use the % (modulo) operator (see Binary arithmetic operations) to ensure tha the result is in rage [0, 3]:
if event.key == pygame.K_LEFT:
snake.direction = (snake.direction - 1) % 4
if event.key == pygame.K_RIGHT:
snake.direction = (snake.direction + 1) % 4
Solution 2:[2]
if event.key == pygame.K_LEFT:
if snake.direction == 0
snake.direction = 2
elif snake.direction == 2
snake.direction = 1
elif snake.direction == 1
snake.direction = 3
elif snake.direction == 3
snake.direction = 0
elif event.key == pygame.K_RIGHT:
if snake.direction == 0
snake.direction = 3
elif snake.direction == 3
snake.direction = 1
elif snake.direction == 1
snake.direction = 2
elif snake.direction == 2
snake.direction = 0
def move(self):
if self.direction is 0:
self.dy = -self.block
self.dx = 0
if self.direction is 1:
self.dy = self.block
self.dx = 0
if self.direction is 2:
self.dy = 0
self.dx = -self.block
if self.direction is 3:
self.dy = 0
self.dx = self.block
self.x += self.dx
self.y += self.dy
This should rotate your snake based on the direction it was traveling before.
Solution 3:[3]
Rather than set the direction based on keypress, have the left and right keys adjust the direction by adding or subtracting from the current direction.
I've also changed the move function so that the directions are in clockwise order.
if event.key == pygame.K_LEFT:
snake.direction -= 1
elif event.key == pygame.K_RIGHT:
snake.direction += 1
if snake.direction > 3:
snake.direction = 0
elif snake.direction < 0:
snake.direction = 3
def move(self):
if self.direction is 0:
self.dy = -self.block
self.dx = 0
if self.direction is 1:
self.dy = 0
self.dx = -self.block
if self.direction is 2:
self.dy = self.block
self.dx = 0
if self.direction is 3:
self.dy = 0
self.dx = self.block
self.x += self.dx
self.y += self.dy
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Rabbid76 |
| Solution 2 | Dharman |
| Solution 3 | Green-Avocado |