2. Learning to Fly
Enough is enough! We have tinkered with some cool things in the last two issues but, as of yet, we haven’t got anything playable! Time to change that by making it possible to fly your player around your world. First, update your code to look like the below. Note we have now introduced line numbers – don’t type them in, they’re just there to make it easier for us to refer back to the code!
TOP TIP: There is probably an option in the text editor you are using to either display line numbers alongside your code (exactly as we have done below) or show the line number the cursor is on at the bottom of the screen.
from direct.showbase.ShowBase import ShowBase
from direct.task import Task
import sys
class ShooterGame(ShowBase):
def __init__(self):
ShowBase.__init__(self)
self.world = self.loader.loadModel("world.bam")
self.world.reparentTo(self.render)
# relevant for world boundaries
self.worldsize = 1024
self.player = self.loader.loadModel("alliedflanker.egg")
self.player.setPos(self.world,200,200,65)
self.player.setH(self.world,225)
self.player.reparentTo(self.render)
# A task to run every frame, some keyboard setup and our speed
self.taskMgr.add(self.updateTask, "update")
self.keyboardSetup()
self.speed = 0.0
self.maxspeed = 100.0
self.player.setScale(.2,.2,.2)
# performance (to be masked later by fog) and view:
self.maxdistance = 400
self.camLens.setFar(self.maxdistance)
self.camLens.setFov(60)
def keyboardSetup(self):
self.keyMap = {"left":0, "right":0, "climb":0, "fall":0, \
"accelerate":0, "decelerate":0, "fire":0}
self.accept("escape", sys.exit)
self.accept("a", self.setKey, ["accelerate",1])
self.accept("a-up", self.setKey, ["accelerate",0])
self.accept("z", self.setKey, ["decelerate",1])
self.accept("z-up", self.setKey, ["decelerate",0])
self.accept("arrow_left", self.setKey, ["left",1])
self.accept("arrow_left-up", self.setKey, ["left",0])
self.accept("arrow_right", self.setKey, ["right",1])
self.accept("arrow_right-up", self.setKey, ["right",0])
self.accept("arrow_down", self.setKey, ["climb",1])
self.accept("arrow_down-up", self.setKey, ["climb",0])
self.accept("arrow_up", self.setKey, ["fall",1])
self.accept("arrow_up-up", self.setKey, ["fall",0])
self.accept("space", self.setKey, ["fire",1])
self.accept("space-up", self.setKey, ["fire",0])
base.disableMouse() # or updateCamera will fail!
def setKey(self, key, value):
self.keyMap[key] = value
def updateTask(self, task):
self.updatePlayer()
self.updateCamera()
return Task.cont
def updatePlayer(self):
# Global Clock
# by default, panda runs as fast as it can frame to frame
scalefactor = (globalClock.getDt()*self.speed)
climbfactor = scalefactor * 0.5
bankfactor = scalefactor
speedfactor = scalefactor * 2.9
# Climb and Fall
if (self.keyMap["climb"]!=0 and self.speed > 0.00):
# faster you go, quicker you climb
self.player.setZ(self.player.getZ()+climbfactor)
self.player.setR(self.player.getR()+climbfactor)
# quickest return: (avoids uncoil/unwind)
if (self.player.getR() >= 180):
self.player.setR(-180)
elif (self.keyMap["fall"]!=0 and self.speed > 0.00):
self.player.setZ(self.player.getZ()-climbfactor)
self.player.setR(self.player.getR()-climbfactor)
# quickest return:
if (self.player.getR() <= -180):
self.player.setR(180)
# autoreturn - add a bit regardless to make sure it happens
elif (self.player.getR() > 0):
self.player.setR(self.player.getR()-(climbfactor+0.1))
if (self.player.getR() < 0):
self.player.setR(0) # avoid jitter
elif (self.player.getR() < 0):
self.player.setR(self.player.getR()+(climbfactor+0.1))
if (self.player.getR() > 0):
self.player.setR(0)
# Left and Right
if (self.keyMap["left"]!=0 and self.speed > 0.0):
self.player.setH(self.player.getH()+bankfactor)
self.player.setP(self.player.getP()+bankfactor)
# quickest return:
if (self.player.getP() >= 180):
self.player.setP(-180)
elif (self.keyMap["right"]!=0 and self.speed > 0.0):
self.player.setH(self.player.getH()-bankfactor)
self.player.setP(self.player.getP()-bankfactor)
if (self.player.getP() <= -180):
self.player.setP(180)
# autoreturn
elif (self.player.getP() > 0):
self.player.setP(self.player.getP()-(bankfactor+0.1))
if (self.player.getP() < 0):
self.player.setP(0)
elif (self.player.getP() < 0):
self.player.setP(self.player.getP()+(bankfactor+0.1))
if (self.player.getP() > 0):
self.player.setP(0)
# throttle control
if (self.keyMap["accelerate"]!=0):
self.speed += 1
if (self.speed > self.maxspeed):
self.speed = self.maxspeed
elif (self.keyMap["decelerate"]!=0):
self.speed -= 1
if (self.speed < 0.0):
self.speed = 0.0
# move forwards - our X/Y is inverted, see the issue
self.player.setX(self.player,-speedfactor)
# respect max camera distance else you
# cannot see the floor post loop the loop!
if (self.player.getZ() > self.maxdistance):
self.player.setZ(self.maxdistance)
# should never happen once we add collision, but in case:
elif (self.player.getZ() < 0):
self.player.setZ(0)
# and now the X/Y world boundaries:
if (self.player.getX() < 0):
self.player.setX(0)
elif (self.player.getX() > self.worldsize):
self.player.setX(self.worldsize)
if (self.player.getY() < 0):
self.player.setY(0)
elif (self.player.getY() > self.worldsize):
self.player.setY(self.worldsize)
def updateCamera(self):
# see issue content for how we calculated these:
self.camera.setPos(self.player, 25.6225, 3.8807, 10.2779)
self.camera.setHpr(self.player,94.8996,-16.6549,1.55508)
my_shooter_game = ShooterGame()
my_shooter_game.run()
Now run your program. You should find you can now move the player around! Use the ‘A’ key to increase speed, ‘Z’ to decrease. With a little speed, the arrow keys will allow you to turn left/right and allow you to climb/fall in the sky. You can even do a loop-the-loop or barrel roll! You can now also quit the game via the ESC key. If you’re not able to see the terrain, your model is likely positioned too high. Simply accelerate a little and then dive, you should see something!
The model itself is actually turning and twisting as you play yet, you will notice, it looks perfectly stationary on your screen – it appears that the camera is twisting and turning to follow. That’s exactly what the code is doing as we will discuss momentarily. It doesn’t have to work that way, you can do all manner of camera trickery, but we have opted for ‘follow the player’ for now.
Notice also you can fly straight through the terrain! Collision with the terrain is something we have yet to consider.