Vector sprite and game stage class (python) at Wednesday, March 12, 2008

As part of a learning exercise for Python I've been porting an old Asteroids clone from Java that I wrote 10 years ago for a digital TV set-top-box.

Here's the first cut of the VectorSprite class and the Stage class. The later sets up the PyGame environment. The VectorSprite class is the basis for all the spites in the game, it handles all the trig functions and currently supports transformation, rotation and scaling.

I'll post the whole game when it's complete as well as posting it on the PyGame site.

#    Pythentic Asteroids - vectorsprites.py
#
#    Copyright (C) 2008  Nick Redshaw
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see .

import pygame, sys, os, math
from pygame.locals import *
from math import *

class VectorSprite: 

def __init__(self, x, y, vx, vy, pointlist, stage):
self.x = x
self.y = y
self.vx = vx
self.vy = vy
self.angle = 0
self.pointlist = pointlist # raw pointlist    
self.rotateAndTransform()
self.stage = stage
self.color = (255,255,255)
self.draw()

# roatate each x,y coord by the angle, then translate it to the x,y position
def rotateAndTransform(self):
newPointList = [self.rotatePoint(point) for point in self.pointlist]
self.transformedPointlist = [self.translatePoint(point) for point in newPointList]

# draw the sprite         
def draw(self):
self.boundingRect = pygame.draw.aalines(self.stage.screen, self.color, True, self.transformedPointlist)              

# comment in to see bounding rects
#pygame.draw.rect(self.stage.screen, self.color, self.boundingRect, 1)

# translate each point to the current x, y position  
def translatePoint(self, point):             
newPoint = []
newPoint.append(point[0] + self.x)
newPoint.append(point[1] + self.y)

return newPoint

# Move the sprite by the velocity 
def move(self):     
if self.x <>
self.x = self.stage.dimensions[0]

if self.x > self.stage.dimensions[0]:
self.x = 0

if self.y <>
self.y = self.stage.dimensions[1]

if self.y > self.stage.dimensions[1]:
self.y = 0

self.x = self.x + self.vx
self.y = self.y + self.vy
self.rotateAndTransform()

# Rotate a point by the given angle
def rotatePoint(self, point):
newPoint = []
cosVal = math.cos(radians(self.angle))
sinVal = math.sin(radians(self.angle))
newPoint.append(point[0] * cosVal + point[1] * sinVal)
newPoint.append(point[1] * cosVal - point[0] * sinVal)
return newPoint

# Scale a point
def scale(self, point, scale):
newPoint = []
newPoint.append(point[0] * scale)
newPoint.append(point[1] * scale)
return newPoint

def collidesWith(self, target):
if self.boundingRect.colliderect(target.boundingRect):
return True
else:
return False


#    Pythentic Asteroids - stage.py
#    Copyright (C) 2008  Nick Redshaw
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see .

import pygame, sys, os

class Stage:

def __init__(self, dimensions, caption):
pygame.init()
pygame.display.set_mode(dimensions)
pygame.display.set_caption(caption)
self.screen = pygame.display.get_surface()
self.spriteList = []
self.dimensions = dimensions

def addSprite(self, sprite):
self.spriteList.append(sprite)

def removeSprite(self, sprite):     
self.spriteList.remove(sprite)

def drawSprites(self):
for sprite in self.spriteList:
sprite.draw()

def moveSprites(self):
for sprite in self.spriteList:
sprite.move()