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@momorprods
Last active Aug 29, 2015
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Raycasting renderer for Pythonista
# RayCast
# Simple raycasting based renderer
# Touch the left part to rotate, and touch the right part to move forward
# Coded in a few hours during my holidays, July 2014, straight from my iPhone - thanks Pythonista !!!
# Feel free to upgrade !
# Enjoy !
# Emmanuel ICART
# eicart@momorprods.com
from scene import *
from math import *
# rendering step - 1=best(slower)
RENDERING_STEP=2
# level data
# 1 = wall, 0 = empty
level = [[1,1,1,1,1,1,1,1],
[1,1,0,0,0,0,0,1],
[1,0,0,0,0,1,0,1],
[1,0,1,0,0,0,0,1],
[1,1,0,0,0,1,0,1],
[1,0,0,1,1,0,0,1],
[1,0,0,0,0,0,0,1],
[1,1,1,1,1,1,1,1]]
LX=len(level[0])
LZ=len(level)
CellSize=128
scan=10
# player
xo=CellSize*LX/2
zo=CellSize*LZ/2
angle=45.0
fov=80
class RayCastScene (Scene):
def setup(self):
# preload the texture
self.texture='PC_Chest_Closed'
self.screenWidth=int(self.size.w)
self.screenHeight=int(self.size.h)
self.xTouchStart=0
self.yTouchStart=0
load_image(self.texture)
pass
def draw(self):
global angle
global xo
global zo
# This will be called for every frame (typically 60 times per second).
# clear background
background(0, 0, 0)
focale=0.5*self.screenWidth/tan(radians(fov/2))
# compute each screen column
for column in xrange(0,self.screenWidth,RENDERING_STEP):
scan_angle=angle+((float(column)-self.screenWidth/2)*fov)/self.screenWidth
c=cos(radians(scan_angle))
s=sin(radians(scan_angle))
if abs(c)<0.001:
if c>0:
c=0.001
else:
c=-0.001
if abs(s)<0.001:
if s>0:
s=0.001
else:
s=-0.001
t2=s/c
t1=c/s
ok1=True
ok2=True
#Initialization of ray casting
pz1=t2*CellSize
if c>0:
px1=CellSize
ini=0
else:
px1=-CellSize
pz1=-pz1
ini=CellSize-1
xp1=ini+(((int)(xo/CellSize))*CellSize)
zp1=zo+((xp1-xo)*pz1)/px1
px2=t1*CellSize
if s>0:
pz2=CellSize
ini=0
else:
pz2=-CellSize
px2=-px2
ini=CellSize-1
zp2=ini+(((int)(zo/CellSize))*CellSize)
xp2=xo+((zp2-zo)*px2)/pz2
#****** cast a ray for z walls ******
compteur=0
while True:
xp1+=px1
zp1+=pz1
compteur+=1
xd=(int)(xp1/CellSize) % LX
zd=(int)(zp1/CellSize) % LZ
if (xd<0): xd=0
if (zd<0): zd=0
if level[xd][zd]!=0 or compteur>=scan: break
if (compteur==scan):ok1=False
distance1=(xp1-xo)/c
col1=(zp1 % CellSize)
if (px1<=0): col1=CellSize-1-col1
#****** cast a ray for x walls ******
compteur=0
while True:
xp2+=px2
zp2+=pz2
compteur+=1
xd=(int)(xp2/CellSize) % LX
zd=(int)(zp2/CellSize) % LZ
if (xd<0):xd=0
if (zd<0):zd=0
if level[xd][zd]!=0 or compteur>=scan: break
if (compteur==scan): ok2=False
distance2=(zp2-zo)/s
col2=(xp2 % CellSize)
if (pz2>=0):col2=CellSize-1-col2
#Choose the nearest wall (x or z)
if (distance1<distance2):
distance=1+(distance1)
colonne=col1
else:
distance=1+(distance2)
colonne=col2
if ok1 or ok2:
# fix the fishbowl effect
distance=distance*cos(radians(angle-scan_angle))
#compute the wall screen height
hauteur = ((CellSize*focale)/distance)
# draw the column
ximage=(colonne*128)/CellSize # 101 x 171 tile
image(self.texture,column,(self.screenHeight-hauteur)/2,RENDERING_STEP,hauteur,ximage,0,RENDERING_STEP,171)
# display fingers
fill(1, 0, 0)
for touch in self.touches.values():
ellipse(touch.location.x - 50, touch.location.y - 50, 100, 100)
# rotation control
if (touch.location.x<self.screenWidth/2):
angle += 0.04*(touch.location.x-self.xTouchStart)
else:
# displacement control
speed=(touch.location.y-self.yTouchStart)*0.2
dx=speed*cos(radians(angle))
dz=speed*sin(radians(angle))
if level[int((xo+dx)/CellSize)][int(zo/CellSize)]!=0:dx=0
if level[int(xo/CellSize)][int((zo+dz)/CellSize)]!=0:dz=0
xo+=dx
zo+=dz
def touch_began(self, touch):
global angle
self.angleStart=angle
if touch.location.x<self.screenWidth/2:self.xTouchStart=touch.location.x
else:
self.yTouchStart=touch.location.y
pass
def touch_moved(self, touch):
pass
def touch_ended(self, touch):
pass
run(RayCastScene(),LANDSCAPE)
@cclauss

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@cclauss cclauss commented Jul 1, 2015

If you copy this code to a Repo then I would be interested to make a few pull requests. It would be cool to try to add the motion module to this so that the scene would change without touching the screen as you change the yaw, pitch, and roll of your device. Your thoughts?

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