Alex's .py

Hi, I'm Alex. I created this Python blog to show people the latest games and code I'm working on, along with explanations and examples for anyone looking to learn more about Python, CGI / server-side programming, or just internet game development in general. Let me know what you think, and thanks for visiting!

Jan 14, 2012 : rand_pool.py

Here's a breakdown of how the rand_pool.py source code works, in 8 easy steps...

Import the PIL module. (Note: this requires Python v2.7)...

#!/home1/alexspyc/python/bin/python import cgitb cgitb.enable() import os, sys import PIL, random, math from PIL import Image, ImageDraw, ImageFont

Create a 550 x 1000 pixel drawing object...

size = [550,1000] # size of the image im = Image.new('RGB', size) # create the image draw = ImageDraw.Draw(im) # create drawing object to draw on

Define variables for the widths and colors of the pool table geometry...

text_col = (255,255,255) pocket_c = 53 od_pocket = 56 rail_width = 50 RGB_ball = (random.randint(0,255),random.randint(0,255),random.randint(0,255)) RGB_felt = (0, 190, 0) RGB_ghost= (25, 215, 25) RGB_rail = (75, 75, 0) pocket_xy = [[pocket_c-od_pocket/2, pocket_c-od_pocket/2, pocket_c+od_pocket/2, pocket_c+od_pocket/2], [pocket_c-od_pocket/2, size[1]/2-od_pocket/2, pocket_c+od_pocket/2, size[1]/2+od_pocket/2], [pocket_c-od_pocket/2, size[1]-pocket_c-od_pocket/2, pocket_c+od_pocket/2, size[1]-pocket_c+od_pocket/2], [size[0]-pocket_c-od_pocket/2, pocket_c-od_pocket/2, size[0]-pocket_c+od_pocket/2, pocket_c+od_pocket/2], [size[0]-pocket_c-od_pocket/2, size[1]/2-od_pocket/2, size[0]-pocket_c+od_pocket/2, size[1]/2+od_pocket/2], [size[0]-pocket_c-od_pocket/2, size[1]-pocket_c-od_pocket/2, size[0]-pocket_c+od_pocket/2, size[1]-pocket_c+od_pocket/2]]

Draw the pool table, the rails and the pockets...

draw.rectangle((0, size[1], size[0], 0), fill=RGB_rail) for i in [1, 4]: # draw side pockets draw.ellipse(pocket_xy[i], fill=(0,0,0)) draw.rectangle((rail_width, size[1]-rail_width, size[0]-rail_width,rail_width), fill=RGB_felt) for i in [0, 2, 3, 5]: # draw corner pockets draw.ellipse(pocket_xy[i], fill=(0,0,0))

Define random positions for the cue ball and object ball then draw them onto the main image...

od_ball= 2 + od_pocket/2 cue_xy = [random.randint(pocket_c,size[0]-pocket_c), random.randint(pocket_c,size[1]-pocket_c)] obj_xy = [random.randint(pocket_c,size[0]-pocket_c), random.randint(pocket_c,size[1]-pocket_c)] draw.ellipse((cue_xy[0]-od_ball/2, cue_xy[1]-od_ball/2, cue_xy[0]+od_ball/2, cue_xy[1]+od_ball/2), fill=(255,255,255))

Determine which pocket has the easiest angle to shoot into and draw a line to it...

ang_to_pk = [] for i in range(len(pocket_xy)): vect_A = [obj_xy[0]-cue_xy[0] , obj_xy[1]-cue_xy[1]] vect_B = [obj_xy[0]-pocket_xy[i][0] , obj_xy[1]-pocket_xy[i][1]] dot_AB = vect_A[0]vect_B[0] + vect_A[1]vect_B[1] D_A = ((cue_xy[0]-obj_xy[0])2 + (cue_xy[1]-obj_xy[1])2).5 D_B = ((obj_xy[0]-pocket_xy[i][0])2 + (obj_xy[1]-pocket_xy[i][1])2).5 ang_to_pk.append([]) ang_to_pk[i] = math.acos(dot_AB/(D_AD_B))180/3.14 best_pocket = ang_to_pk.index(max(ang_to_pk)) Angle = 180 - ang_to_pk[best_pocket] v_pk = [pocket_xy[best_pocket][0] - obj_xy[0], pocket_xy[best_pocket][1] - obj_xy[1]] D_pk = (v_pk[0]2 + v_pk[1]2)**.5 obj_to_ghost = [v_pk[0]1.00od_ball/D_pk, v_pk[1]1.00od_ball/D_pk] ghost_xy = [obj_xy[0] - obj_to_ghost[0], obj_xy[1] - obj_to_ghost[1]] # draw line -- ghost ball center_pocket = [(pocket_xy[best_pocket][0] + pocket_xy[best_pocket][2])/2, (pocket_xy[best_pocket][1] + pocket_xy[best_pocket][3])/2] draw.line(((obj_xy[0], obj_xy[1]),(center_pocket[0], center_pocket[1]))) draw.ellipse((obj_xy[0]-od_ball/2, obj_xy[1]-od_ball/2, obj_xy[0]+od_ball/2, obj_xy[1]+od_ball/2), fill=RGB_ball) draw.ellipse((ghost_xy[0]-od_ball/2, ghost_xy[1]-od_ball/2, ghost_xy[0]+od_ball/2, ghost_xy[1]+od_ball/2), fill=RGB_ghost) draw.ellipse((ghost_xy[0]-od_ball.475, ghost_xy[1]-od_ball.475, ghost_xy[0]+od_ball.475, ghost_xy[1]+od_ball.475), fill=RGB_felt) draw.line(((cue_xy[0], cue_xy[1]),(ghost_xy[0], ghost_xy[1])))

Calculate the difficulty of the shot based on its angle and how far it had to go...

D_obj = ((obj_xy[0]-cue_xy[0])2 + (obj_xy[1]-cue_xy[1])2)**.5 D_obj_ft = D_obj * 9/(size[1]-2rail_width) - .2 D_pk_ft = D_pk 9/(size[1]-2*rail_width) - .6 if D_pk_ft < .5: x = .5 else: x = (D_obj_ft1 + D_pk_ft1)**1 if x > 9: x = 9 y = Angle; y1 = 0; y2 = 90 if x < 5: x1 = 1; x2 = 5; Q11 = 100; Q21 = 95; Q12 = 80; Q22 = 33 else: x1 = 1; x2 = 5; Q11 = 95; Q21 = 80; Q12 = 33; Q22 = 5 div = (x2-x1)(y2-y1) P = (Q11(x2-x)(y2-y)+Q21(x-x1)(y2-y)+Q12(x2-x)(y-y1)+Q22(x-x1)(y-y1))/div im = im.rotate(90) draw = ImageDraw.Draw(im) # respecify img object to draw on text = "Dist to object = " + str(round(D_obj_ft10)/10) + "'" text = text + ", Dist to pk = " + str(round(D_pk_ft*10)/10) + "'" text = text + ", Angle = " + str(int(round(Angle))) + " deg" text = text + ", Accuracy = " + str(int(round(P))) + "%" text_pos = (30,size[0]-37) # (obj_xy[0]+od_ball, obj_xy[1]) fontPath = "http://alexspy.com/cgi-bin/ariblk.ttf" #my_font = ImageFont.truetype(fontPath,24) draw.text(text_pos, text, fill=text_col) # , font=my_font

Save changes to the drawing object and print its JPEG binary code back to the browser seeking to retrieve and render the image...

from cStringIO import StringIO tmp = StringIO() im.save(tmp, 'JPEG') tmp.seek(0) s = tmp.read() print "Content-type: image/jpg" print print s,

Here's some other great python blogs I like to check out:

Nadia Alramli's Blog
The "Invent with Python" Blog
Carter Sande's Blog