Pygame鼠标速度

Question

我是编码新手，pygame 我正在寻找代码来检查鼠标是否以特定速度移动。如果是，那就退出游戏。

if the mouse speed is greater than say 10 pixels per second
     Run = False

Answer 1

你可以通过pygame.mouse.get_pos()函数跟踪鼠标位置的每一帧，当它发生变化时，检查从pygame.time.get_ticks()开始的时间。

类似于：

MAX_SPEED = 50

previous_mouse_position = None
previous_sample_time    = None
...

current_mouse_pos = pygame.mouse.get_pos()
if ( previous_mouse_position != current_mouse_pos ):
    # mouse has moved
    pixels_movement = distance( previous_mouse_position, current_mouse_pos )
    time_now        = pygame.time.get_ticks()
    movement_time   = ( time_now - previous_sample_time ) / 1000  # milliseconds -> seconds
    movement_speed = pixels_movement / movement_time
    if ( movement_speed > MAX_SPEED ):
        doSomething()

elif ( previous_mouse_position == None ):
    # No previous recorded position
    previous_mouse_position = current_mouse_pos
    previous_sample_time    = pygame.time.get_ticks()

当然 euclidian distance between two points 可以很容易地计算出来。

编辑：

import math

def distance( point1, point2 ):
    """ Return the Euclidian distance between two points 
        Ref: https://en.wikipedia.org/wiki/Euclidean_distance#Two_dimensions """
    # NOTE: this code hasn't been tested
    p1x, p1y  = point1
    p2x, p2y  = point2
    x_squared = ( p2x - p1x ) * ( p2x - p1x )
    y_squared = ( p2y - p1y ) * ( p2y - p1y )
    pixel_dist= math.sqrt( x_squared + y_squared )
    return pixel_dist

Answer 2

MOUSEMOTION事件有一个属性rel表示鼠标相对于之前位置移动了多少。使用此属性，我们可以使用毕达哥拉斯定理计算速度（** 表示 Python 中的功率）。因此，在您的事件循环中，您可以执行以下操作：

for event in pygame.event.get():
    if event.type == pygame.MOUSEMOTION:
        dx, dy = event.rel
        speed = (dx ** 2 + dy ** 2) ** (1/2)  # Pythagoras theorem.
        if speed >= MAX_SPEED:
            quit()  # Or show quit screen or whatever.

确保在循环之前定义 MAX_SPEED（例如作为全局变量）。

这种方法的一个问题是第一个事件将具有相对于原点的位置，即如果游戏开始时您的鼠标位于 (100, 100)，则 rel 属性将为 (100 , 100).

由于您可能不想在申请开始时就强制执行您的游戏规则，这应该不是问题。但是，如果您希望游戏在强制执行此规则的情况下打开，则需要跳过第一个 MOUSEMOTION 事件。这可以通过检查布尔值来完成。

# Define this globally (or somewhere where it will only be set on startup).
# Also, use a better name than 'first'. Something that represent the logic for your game. 
first = False


for event in pygame.event.get():
    if event.type == pygame.MOUSEMOTION:
        dx, dy = event.rel
        speed = (dx ** 2 + dy ** 2) ** (1/2)  # Pythagoras theorem.
        if speed >= MAX_SPEED and first:
            quit()  # Or show quit screen or whatever.
        first = True

Pygame鼠标速度

Pygame mouse speed

python

pygame

mouse