Page 6

ISSUE 4: What goes up…

Add collisions.  Add gravity. Add explosions. Add water. Add camera tricks. Improve fog, lighting, sky. Issue 4, all done!
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ISSUE 4 APPENDIX: Full Game Code

from direct.showbase.ShowBase import ShowBase
from direct.task import Task
from direct.interval.LerpInterval import LerpTexOffsetInterval, LerpPosInterval
from pandac.PandaModules import CompassEffect, CollisionTraverser, CollisionNode
from pandac.PandaModules import CollisionSphere, CollisionHandlerQueue, Material
from pandac.PandaModules import VBase4, VBase3, TransparencyAttrib
from panda3d.core import AmbientLight, DirectionalLight, Vec4, Vec3, Fog
from panda3d.core import BitMask32, Texture, TextNode, TextureStage
from panda3d.core import NodePath, PandaNode
from direct.gui.OnscreenText import OnscreenText
import sys

class MyApp(ShowBase):
    def __init__(self):
        ShowBase.__init__(self)
        self.debug = False
        self.statusLabel = self.makeStatusLabel(0)
        self.collisionLabel = self.makeStatusLabel(1)

        self.world = self.loader.loadModel("models/world.bam")
        self.world.reparentTo(self.render)

        # relevant for world boundaries
        self.worldsize = 1024

        self.maxspeed = 100.0
        self.startPos = Vec3(200,200,65)
        self.startHpr = Vec3(225,0,0)
        self.player = self.loader.loadModel("models/alliedflanker")
        self.player.setScale(.2,.2,.2)
        self.player.reparentTo(self.render)
        self.resetPlayer()

        # A task to run every frame, some keyboard setup and our speed
        self.taskMgr.add(self.updateTask, "update")
        self.keyboardSetup()

        # performance (to be masked later by fog) and view:
        self.maxdistance = 400

        if self.debug == False:
            self.camLens.setFar(self.maxdistance)
        else:
            base.oobe()

        self.camLens.setFov(60)
        self.createEnvironment()
        self.setupCollisions()
        self.textCounter = 0

        # load the explosion ring
        self.explosionModel = self.loader.loadModel('models/explosion')
        self.explosionModel.reparentTo(self.render)
        self.explosionModel.setScale(0.0)
        self.explosionModel.setLightOff()
        # only one explosion at a time:
        self.exploding = False

    def resetPlayer(self):
        self.player.show()
        self.player.setPos(self.world,self.startPos)
        self.player.setHpr(self.world,self.startHpr)
        self.speed = self.maxspeed/2

    def makeStatusLabel(self, i):
        return OnscreenText(style=2, fg=(.5,1,.5,1), pos=(-1.3,0.92-(.08 * i)),align=TextNode.ALeft, scale = .08, mayChange = 1)

    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 createEnvironment(self):
        # Fog
        expfog = Fog("scene-wide-fog")
        expfog.setColor(0.5,0.5,0.5)
        expfog.setExpDensity(0.002)
        self.render.setFog(expfog)

        # Our sky
        skysphere = self.loader.loadModel('models/blue-sky-sphere')
        skysphere.setEffect(CompassEffect.make(self.render))
        skysphere.setScale(0.08)
        # NOT render or you'll fly through the sky!:
        skysphere.reparentTo(self.camera) 

        # Our lighting
        ambientLight = AmbientLight("ambientLight")
        ambientLight.setColor(Vec4(.6, .6, .6, 1))
        self.render.setLight(self.render.attachNewNode(ambientLight))

        directionalLight = DirectionalLight("directionalLight")
        directionalLight.setColor(VBase4(0.8, 0.8, 0.5, 1))
        dlnp = self.render.attachNewNode(directionalLight)
        dlnp.setPos(0,0,260)
        dlnp.lookAt(self.player)
        self.render.setLight(dlnp)

        # water
        self.water = self.loader.loadModel('models/square.egg')
        self.water.setSx(self.worldsize*2)
        self.water.setSy(self.worldsize*2)
        self.water.setPos(self.worldsize/2,self.worldsize/2,25) # sea level
        self.water.setTransparency(TransparencyAttrib.MAlpha) 
        newTS = TextureStage('1')
        self.water.setTexture(newTS,self.loader.loadTexture('models/water.png'))
        self.water.setTexScale(newTS,4)
        self.water.reparentTo(self.render)
        LerpTexOffsetInterval(self.water, 200, (1,0),(0,0), textureStage=newTS).loop()

    def setupCollisions(self):
        self.collTrav = CollisionTraverser()

        self.playerGroundSphere = CollisionSphere(0,1.5,-1.5,1.5)
        self.playerGroundCol = CollisionNode('playerSphere')
        self.playerGroundCol.addSolid(self.playerGroundSphere)

        # bitmasks
        self.playerGroundCol.setFromCollideMask(BitMask32.bit(0))
        self.playerGroundCol.setIntoCollideMask(BitMask32.allOff())
        self.world.setCollideMask(BitMask32.bit(0))
        self.water.setCollideMask(BitMask32.bit(0))

        # and done
        self.playerGroundColNp = self.player.attachNewNode(self.playerGroundCol)
        self.playerGroundHandler = CollisionHandlerQueue()
        self.collTrav.addCollider(self.playerGroundColNp, self.playerGroundHandler)

        # DEBUG as per video:
        if (self.debug == True):
            self.playerGroundColNp.show()
            self.collTrav.showCollisions(self.render)

    def updateTask(self, task):

        self.updatePlayer()
        self.updateCamera()

        self.collTrav.traverse(self.render)
        for i in range(self.playerGroundHandler.getNumEntries()):
            entry = self.playerGroundHandler.getEntry(i)
            if (self.debug == True):
                self.collisionLabel.setText("DEAD:"+str(globalClock.getFrameTime()))
            if (self.exploding == False):
                self.player.setZ(entry.getSurfacePoint(self.render).getZ()+10)
                self.explosionSequence()
        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 * 0.3
        bankfactor  = scalefactor
        speedfactor = scalefactor * 2.9
        gravityfactor = ((self.maxspeed-self.speed)/100.0)*2.0

        # 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()+(0.5*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()-(0.5*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
        if self.exploding == False:
            self.player.setX(self.player,-speedfactor)
            self.applyBoundaries()
            self.player.setZ(self.player,-gravityfactor)

    def applyBoundaries(self):
        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:
        boundary = False        
        if (self.player.getX() < 0):
            self.player.setX(0)
            boundary = True
        elif (self.player.getX() > self.worldsize):
            self.player.setX(self.worldsize)
            boundary = True
        if (self.player.getY() < 0):
            self.player.setY(0)
            boundary = True
        elif (self.player.getY() > self.worldsize):
            self.player.setY(self.worldsize)
            boundary = True

        # lets not be doing this every frame... 
        if boundary == True and self.textCounter > 30:
            self.statusLabel.setText("STATUS: MAP END; TURN AROUND")
        elif self.textCounter > 30:
            self.statusLabel.setText("STATUS: OK")

        if self.textCounter > 30:
            self.textCounter = 0
        else:
            self.textCounter = self.textCounter + 1

    def updateCamera(self):
        # see issue content for how we calculated these:
        percent = (self.speed/self.maxspeed)
        self.camera.setPos(self.player, 19.6225+(10*percent), 3.8807, 10.2779)
        self.camera.setHpr(self.player,94.8996,-12.6549, 1.55508)

    def explosionSequence(self):
        self.exploding = True
        self.explosionModel.setPosHpr( Vec3(self.player.getX(),self.player.getY(), \
                                       self.player.getZ()), Vec3( self.player.getH(),0,0))
        self.player.hide()
        taskMgr.add( self.expandExplosion, 'expandExplosion' )

    def expandExplosion( self, Task ):
        # expand the explosion rign each frame until a certain size
        if self.explosionModel.getScale( ) < VBase3( 60.0, 60.0, 60.0 ):
            factor = globalClock.getDt()
            scale = self.explosionModel.getScale()
            scale = scale + VBase3( factor*40, factor*40, factor*40 )
            self.explosionModel.setScale(scale)
            return Task.cont
        else:
            self.explosionModel.setScale(0)
            self.exploding = False
            self.resetPlayer()
            # and it stops the task

app = MyApp()
app.run()

Goto Issue 5 >>>

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