raycast.py

raycast.py

# 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)