Differences between revisions 5 and 39 (spanning 34 versions)
⇤ ← Revision 5 as of 2002-07-19 08:45:57 →
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Editor: taoriver
Comment: Added my experience working games with Python.
← Revision 39 as of 2010-06-07 08:37:40 → ⇥
Size: 4016
Editor: smp-82-167
Comment: good
Deletions are marked like this. Additions are marked like this.
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= Game Programming With Python = # Copyright (c) 2005 Nokia Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
Line 3: Line 15:
You can write whole games in Python using [http://www.pygame.org/ PyGame]. import appuifw
from graphics import *
import e32
from key_codes import *
Line 5: Line 20:
If you have an existing game and want to add a scripting engine to make it more flexible, Python is also a very good choice. But you'll have to learn about IntegratingPythonWithOtherLanguages. class Keyboard(object):
    def __init__(self,onevent=lambda:None):
        self._keyboard_state={}
        self._downs={}
        self._onevent=onevent
    def handle_event(self,event):
        if event['type'] == appuifw.EEventKeyDown:
            code=event['scancode']
            if not self.is_down(code):
                self._downs[code]=self._downs.get(code,0)+1
            self._keyboard_state[code]=1
        elif event['type'] == appuifw.EEventKeyUp:
            self._keyboard_state[event['scancode']]=0
        self._onevent()
    def is_down(self,scancode):
        return self._keyboard_state.get(scancode,0)
    def pressed(self,scancode):
        if self._downs.get(scancode,0):
            self._downs[scancode]-=1
            return True
        return False
keyboard=Keyboard()
Line 7: Line 43:
Read [http://www.onlamp.com/pub/a/python/2002/07/11/pythonnews.html Humongous Python] for a case study. appuifw.app.screen='full'
img=None
def handle_redraw(rect):
    if img:
        canvas.blit(img)
appuifw.app.body=canvas=appuifw.Canvas(
    event_callback=keyboard.handle_event,
    redraw_callback=handle_redraw)
img=Image.new(canvas.size)
Line 9: Line 53:
== Testimony == running=1
def quit():
    global running
    running=0
appuifw.app.exit_key_handler=quit
Line 11: Line 59:
I tried porting [http://taoriver.net/eouwiki/ Escape of the Unicorn] to Python/PySDL, but the game dropped from 30 fps to 6 fps. location=[img.size[0]/2,img.size[1]/2]
speed=[0.,0.]
blobsize=16
xs,ys=img.size[0]-blobsize,img.size[1]-blobsize
gravity=0.03
acceleration=0.05
Line 13: Line 66:
After a lot of profiling and unrolling screen draw code, I was able to reach 8 frames a second. import time
start_time=time.clock()
n_frames=0
# To speed things up, we prerender the text.
labeltext=u'Use arrows to move ball'
textrect=img.measure_text(labeltext, font='normal')[0]
text_img=Image.new((textrect[2]-textrect[0],textrect[3]-textrect[1]))
text_img.clear(0)
text_img.text((-textrect[0],-textrect[1]),labeltext,fill=0xffffff,font='normal')
Line 15: Line 76:
If you look at PyGame and PySDL games, you'll notice that they aren't action or arcade games. while running:
    img.clear(0)
    img.blit(text_img, (0,0))
    img.point((location[0]+blobsize/2,location[1]+blobsize/2),
              0x00ff00,width=blobsize)
    handle_redraw(())
    e32.ao_yield()
    speed[0]*=0.999
    speed[1]*=0.999
    speed[1]+=gravity
    location[0]+=speed[0]
    location[1]+=speed[1]
    if location[0]>xs:
        location[0]=xs-(location[0]-xs)
        speed[0]=-0.80*speed[0]
        speed[1]=0.90*speed[1]
    if location[0]<0:
        location[0]=-location[0]
        speed[0]=-0.80*speed[0]
        speed[1]=0.90*speed[1]
    if location[1]>ys:
        location[1]=ys-(location[1]-ys)
        speed[0]=0.90*speed[0]
        speed[1]=-0.80*speed[1]
    if location[1]<0:
        location[1]=-location[1]
        speed[0]=0.90*speed[0]
        speed[1]=-0.80*speed[1]
        
    if keyboard.is_down(EScancodeLeftArrow): speed[0] -= acceleration
    if keyboard.is_down(EScancodeRightArrow): speed[0] += acceleration
    if keyboard.is_down(EScancodeDownArrow): speed[1] += acceleration
    if keyboard.is_down(EScancodeUpArrow): speed[1] -= acceleration
    if keyboard.pressed(EScancodeHash):
        filename=u'e:\\screenshot.png'
        canvas.text((0,32),u'Saving screenshot to:',fill=0xffff00)
        canvas.text((0,48),filename,fill=0xffff00)
        img.save(filename)
Line 17: Line 115:
I have only heard of few efforts that succeeded in embedding Python in C++, and I have forgotten them. For the most part, people (including Humongous, as described in [http://www.onlamp.com/pub/a/python/2002/07/11/pythonnews.html the case study described]) extend Python with C++. If you are going to mix Python and C++, I think it is best to extend Python- that is the intended direction. I consider this a failing of Python.     n_frames+=1
end_time=time.clock()
total=end_time-start_time
Line 19: Line 119:
If you want to embed a scripting system because you already have a huge system, embed something like Guile. I think it is an inferior solution, but that it will result in a lot less heartbreak.

I suspect I'll try to rewrite Escape of the Unicorn as a C++/Python mixture some day, and pay careful attention to how I cut the C++/Python lines.
I think only a few things need to be given to C++, such as display loops, animation management, and collision detection.

-- LionKimbro [[DateTime(2002-07-19T10:45:57)]]		 print "%d frames, %f seconds, %f FPS, %f ms/frame."%(n_frames,total,
                                                     n_frames/total,
                                                     total/n_frames*1000.)

# # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License.

import appuifw from graphics import * import e32 from key_codes import *

class Keyboard(object):

  • def init(self,onevent=lambda:None):

    • self._keyboard_state={} self._downs={} self._onevent=onevent
    def handle_event(self,event):
    • if event['type'] == appuifw.EEventKeyDown:
      • code=event['scancode'] if not self.is_down(code):
        • self._downs[code]=self._downs.get(code,0)+1
        self._keyboard_state[code]=1
      elif event['type'] == appuifw.EEventKeyUp:
      • self._keyboard_state[event['scancode']]=0
      self._onevent()
    def is_down(self,scancode):
    • return self._keyboard_state.get(scancode,0)
    def pressed(self,scancode):
    • if self._downs.get(scancode,0):
      • self._downs[scancode]-=1 return True
      return False

keyboard=Keyboard()

appuifw.app.screen='full' img=None def handle_redraw(rect):

  • if img:
    • canvas.blit(img)

appuifw.app.body=canvas=appuifw.Canvas(

  • event_callback=keyboard.handle_event, redraw_callback=handle_redraw)

img=Image.new(canvas.size)

running=1 def quit():

  • global running running=0

appuifw.app.exit_key_handler=quit

location=[img.size[0]/2,img.size[1]/2] speed=[0.,0.] blobsize=16 xs,ys=img.size[0]-blobsize,img.size[1]-blobsize gravity=0.03 acceleration=0.05

import time start_time=time.clock() n_frames=0 # To speed things up, we prerender the text. labeltext=u'Use arrows to move ball' textrect=img.measure_text(labeltext, font='normal')[0] text_img=Image.new((textrect[2]-textrect[0],textrect[3]-textrect[1])) text_img.clear(0) text_img.text((-textrect[0],-textrect[1]),labeltext,fill=0xffffff,font='normal')

while running:

  • img.clear(0) img.blit(text_img, (0,0)) img.point((location[0]+blobsize/2,location[1]+blobsize/2),
    • 0x00ff00,width=blobsize)
    handle_redraw(()) e32.ao_yield() speed[0]*=0.999 speed[1]*=0.999 speed[1]+=gravity location[0]+=speed[0] location[1]+=speed[1]

    if location[0]>xs:

    • location[0]=xs-(location[0]-xs) speed[0]=-0.80*speed[0] speed[1]=0.90*speed[1]

    if location[0]<0:

    • location[0]=-location[0] speed[0]=-0.80*speed[0] speed[1]=0.90*speed[1]

    if location[1]>ys:

    • location[1]=ys-(location[1]-ys) speed[0]=0.90*speed[0] speed[1]=-0.80*speed[1]

    if location[1]<0:

    • location[1]=-location[1] speed[0]=0.90*speed[0] speed[1]=-0.80*speed[1]
    if keyboard.is_down(EScancodeLeftArrow): speed[0] -= acceleration if keyboard.is_down(EScancodeRightArrow): speed[0] += acceleration if keyboard.is_down(EScancodeDownArrow): speed[1] += acceleration if keyboard.is_down(EScancodeUpArrow): speed[1] -= acceleration if keyboard.pressed(EScancodeHash):
    • filename=u'e:\\screenshot.png' canvas.text((0,32),u'Saving screenshot to:',fill=0xffff00) canvas.text((0,48),filename,fill=0xffff00) img.save(filename)
    n_frames+=1

end_time=time.clock() total=end_time-start_time

print "%d frames, %f seconds, %f FPS, %f ms/frame."%(n_frames,total,

  • n_frames/total, total/n_frames*1000.)

GameProgramming (last edited 2020-12-03 12:57:14 by ShadowClaw20017)

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