wxPython和pycairo练习记录4
继续写碰撞检测。
4.1 判断碰撞的条件
碰撞，即两个坦克车身产生重合。
因为这里的坦克是四方向的，所以可碰撞的区域概括为编号4和5，不可碰撞区域概括为6和7。已知的是坦克左上角定位点，及坦克的宽高。假设玩家坦克坐标为(x, y)，宽高为(w, h)，其他敌方坦克以编号作下标。
先以正相邻的4号区域来看，4和坦克碰撞，得到条件：
abs(x4 - x) < w4
那么 x 坐标相同且 y 坐标不同的的4567都满足这个条件，所以同时还需要判断 y 坐标：
abs(y4 - y) < h4
再代入编号1234567，发现符合预期。
当然，wxPython 自带的矩形类 wx.Rect 的方法 Intersects 也可以实现同样的效果。
4.2 碰撞后的转向问题
碰撞后谁转向？谁撞了谁？已知两个坦克的前进方向和坐标，可以通过坐标差判断相对位置。
同方向相撞>>，位置在后的转向。
相对方向相撞><，都转向。
不同轴方向相撞>^或^>，撞向侧面的那个转向。
4.3 代码
还是有问题：1.相对方向碰撞时用SetDirection不转向，但是用ChangeDirection可以，这两个方法都是修改_direction，也不知道错在哪；2.转向时依然有重合的地方。
def CheckCollisions(self):
# checked = [] # 存储已检测过的坦克对象
for tank1 in self.enemies:
for tank2 in self.enemies:
# 忽略自身和已检测过的坦克
if tank1 is tank2:
# if tank1 is tank2 or tank2 in checked:
continue
rect1 = tank1.GetRect()
rect2 = tank2.GetRect()
x1, y1, w1, w2 = rect1
x2, y2, w2, h2 = rect2
direction1 = tank1.GetDirection()
direction2 = tank2.GetDirection()
if rect1.Intersects(rect2):
# 同方向相撞>>，位置在后的转向。
# 不同轴方向相撞>^或^>，撞向侧面的那个转向。
# print(wx.WXK_UP, wx.WXK_DOWN, wx.WXK_LEFT, wx.WXK_RIGHT)
# 315 317 314 316
if abs(direction1 - direction2) != 2:
# if direction1 == direction2 or abs(direction1 - direction2) == 1 or abs(direction1 - direction2) == 3:
if direction1 == wx.WXK_UP and y1 >= y2:
tank1.SetDirection(wx.WXK_DOWN)
elif direction1 == wx.WXK_DOWN and y1 <= y2:
tank1.SetDirection(wx.WXK_UP)
elif direction1 == wx.WXK_LEFT and x1 >= x2:
tank1.SetDirection(wx.WXK_RIGHT)
elif direction1 == wx.WXK_RIGHT and x1 <= x2:
tank1.SetDirection(wx.WXK_LEFT)
else:
direction2 = (direction2 <= 315) and (direction2 + 2) or (direction2 - 2)
tank2.SetDirection(direction2)
# 相对方向相撞><，都转向。
else:
# elif abs(direction1 - direction2) == 2:
# TODO: 哪里错了？
# tank1.SetDirection(direction2)
# tank2.SetDirection(direction1)
tank1.ChangeDirection(direction1)
tank2.ChangeDirection(direction2)
# checked.append(tank1)
4.4 效果
# -*- coding: utf-8 -*-
# example2.py
import random
import wx
import wx.lib.wxcairo
import cairo
import board
from display import MovieClip
class cv(board.cv):
"""
常量，用类属性避免使用全局变量
"""
# 面板尺寸
BOARD_WIDTH = 600
BOARD_HEIGHT = 400
class Tank(MovieClip):
def __init__(self, *args, **kwargs):
super(Tank, self).__init__(*args, **kwargs)
self._speed = 10 # 移动速度
self._dx = 0 # x 轴方向
self._dy = 0 # y 轴方向
def Up(self):
self._dy = -1
self._dx = 0
# 同一方向时需要需要排除，不然动画一直停留在第1帧
if self._currentScene != 0:
self.GotoAndPlay(0, 0)
def Down(self):
self._dy = 1
self._dx = 0
if self._currentScene != 1:
self.GotoAndPlay(0, 1)
def Left(self):
self._dx = -1
self._dy = 0
if self._currentScene != 2:
self.GotoAndPlay(0, 2)
def Right(self):
self._dx = 1
self._dy = 0
if self._currentScene != 3:
self.GotoAndPlay(0, 3)
class Player(Tank):
def __init__(self, x, y, path="tank_T1_0.png", rect=(0, 0, 48, 48), fps=100):
super(Player, self).__init__(x, y, path, rect, fps)
def OnKeyDown(self, e):
key = e.GetKeyCode()
if key == wx.WXK_UP:
self.Up()
if key == wx.WXK_DOWN:
self.Down()
if key == wx.WXK_LEFT:
self.Left()
if key == wx.WXK_RIGHT:
self.Right()
self._x += self._dx * self._speed
self._y += self._dy * self._speed
def OnKeyUp(self, e):
key = e.GetKeyCode()
if key == wx.WXK_UP or key == wx.WXK_DOWN:
self._dy = 0
if key == wx.WXK_LEFT or key == wx.WXK_RIGHT:
self._dx = 0
if self._dx == 0 and self._dy == 0:
self.Stop()
class Enemy(Tank):
def __init__(self, x, y, path="tank_T1_0.png", rect=(0, 0, 48, 48), fps=100, mixColor=(0, 1, 1, 0.8)):
self._mixColor = mixColor # 自定义混合颜色
super(Enemy, self).__init__(x, y, path, rect, fps)
# 初始随机方向
self._direction = random.choice([wx.WXK_UP, wx.WXK_DOWN, wx.WXK_LEFT, wx.WXK_RIGHT])
self._speed = 1
self._isPlaying = True
def LoadFrames(self, rect):
# 将图像载为帧前，先改变图像的色相
surface = cairo.ImageSurface.create_from_png("tank_T1_0.png")
sw = surface.get_width()
sh = surface.get_height()
# 创建只显示坦克的 surface 作为混合层
surface2 = cairo.ImageSurface(cairo.FORMAT_ARGB32, sw, sh)
ctx = cairo.Context(surface2)
ctx.set_source_rgba(*self._mixColor)
ctx.mask_surface(surface)
# 与目标图像混合
ctx = cairo.Context(surface)
ctx.set_source_surface(surface2)
ctx.set_operator(cairo.Operator.HSL_HUE) # 将色相和目标图像色相混合
ctx.paint()
self._surface = surface
super().LoadFrames(rect)
def GetDirection(self):
return self._direction
def SetDirection(self, direction):
self._direction = direction
def ChangeDirection(self, direction):
# 方向转换为除指定方向以外的方向，总觉得这样写不太好 加个
# TODO
directions = [wx.WXK_UP, wx.WXK_DOWN, wx.WXK_LEFT, wx.WXK_RIGHT]
directions.remove(direction)
self._direction = random.choice(directions)
def AutoWalk(self):
if self._direction == wx.WXK_UP:
self.Up()
elif self._direction == wx.WXK_DOWN:
self.Down()
elif self._direction == wx.WXK_LEFT:
self.Left()
elif self._direction == wx.WXK_RIGHT:
self.Right()
# 遇边界转向，坦克宽高明明是48，可是按48处理显示不对
# TODO
if self._x < 0:
self._x = 0
self.ChangeDirection(wx.WXK_LEFT)
elif self._x > cv.BOARD_WIDTH - 68:
self._x = cv.BOARD_WIDTH - 68
self.ChangeDirection(wx.WXK_RIGHT)
else:
self._x += self._dx * self._speed
if self._y < 0:
self._y = 0
self.ChangeDirection(wx.WXK_UP)
elif self._y > cv.BOARD_HEIGHT - 96:
self._y = cv.BOARD_HEIGHT - 96
self.ChangeDirection(wx.WXK_DOWN)
else:
self._y += self._dy * self._speed
def Update(self, times, speed):
# 由主程序刷新时更新
self.AutoWalk()
super().Update(times, speed)
class Board(board.Board):
def DrawBackground(self, ctx):
super().DrawBackground(ctx)
text = "SmileBasic"
ctx.set_font_size(40)
_, _, w, h, _, _ = ctx.text_extents(text)
x = (cv.BOARD_WIDTH - w) // 2
y = (cv.BOARD_HEIGHT - h) // 2
# 文字是以首个字左下角坐标定位，而矩形是以左上角定位，y轴相差文字的高度，不需要考虑线条宽度。
# 另外PaintDC是不含标题栏的。
ctx.rectangle(x - 10, y - 10 - h, w + 20, h + 20)
ctx.set_source_rgb(1, 0, 0)
ctx.stroke()
ctx.move_to(x, y)
ctx.set_source_rgb(1, 1, 1)
ctx.show_text(text)
def InitSceneObjects(self):
super().InitSceneObjects()
self.enemies = []
self.player = Player(50, 50) # 实例化一个玩家坦克
self.sceneObjects.append(self.player)
# 坦克在四个角的坐标
coordinates = [(0, 0),
(cv.BOARD_WIDTH - 48, 0),
(0, cv.BOARD_HEIGHT - 48),
(cv.BOARD_WIDTH - 48, cv.BOARD_HEIGHT - 48)]
# 生成10个敌军坦克
for i in range(10):
coord = random.choice(coordinates)
enemy = Enemy(x=coord[0], y=coord[1], mixColor=(random.random(), random.random(), random.random(), 0.8))
self.enemies.append(enemy)
self.sceneObjects.append(enemy)
def DrawSceneObjects(self, ctx):
for so in self.sceneObjects:
ctx.set_source_surface(so.GetSurface(), so.GetX(), so.GetY())
ctx.paint()
def OnKeyDown(self, e):
self.player.OnKeyDown(e)
self.Refresh()
def OnKeyUp(self, e):
self.player.OnKeyUp(e)
def CheckStrategies(self):
self.CheckCollisions()
def CheckCollisions(self):
# checked = [] # 存储已检测过的坦克对象
for tank1 in self.enemies:
for tank2 in self.enemies:
# 忽略自身和已检测过的坦克
if tank1 is tank2:
# if tank1 is tank2 or tank2 in checked:
continue
rect1 = tank1.GetRect()
rect2 = tank2.GetRect()
x1, y1, w1, w2 = rect1
x2, y2, w2, h2 = rect2
direction1 = tank1.GetDirection()
direction2 = tank2.GetDirection()
if rect1.Intersects(rect2):
# 同方向相撞>>，位置在后的转向。
# 不同轴方向相撞>^或^>，撞向侧面的那个转向。
# print(wx.WXK_UP, wx.WXK_DOWN, wx.WXK_LEFT, wx.WXK_RIGHT)
# 315 317 314 316
if abs(direction1 - direction2) != 2:
# if direction1 == direction2 or abs(direction1 - direction2) == 1 or abs(direction1 - direction2) == 3:
if direction1 == wx.WXK_UP and y1 >= y2:
tank1.SetDirection(wx.WXK_DOWN)
elif direction1 == wx.WXK_DOWN and y1 <= y2:
tank1.SetDirection(wx.WXK_UP)
elif direction1 == wx.WXK_LEFT and x1 >= x2:
tank1.SetDirection(wx.WXK_RIGHT)
elif direction1 == wx.WXK_RIGHT and x1 <= x2:
tank1.SetDirection(wx.WXK_LEFT)
else:
direction2 = (direction2 <= 315) and (direction2 + 2) or (direction2 - 2)
tank2.SetDirection(direction2)
# 相对方向相撞><，都转向。
else:
# elif abs(direction1 - direction2) == 2:
# TODO: 哪里错了？
# tank1.SetDirection(direction2)
# tank2.SetDirection(direction1)
tank1.ChangeDirection(direction1)
tank2.ChangeDirection(direction2)
# checked.append(tank1)