212 lines
9.5 KiB
Python
212 lines
9.5 KiB
Python
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#!/usr/bin/env python
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# Author: Shao Zhang and Phil Saltzman
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# Last Updated: 2015-03-13
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#
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# This tutorial will cover fog and how it can be used to make a finite length
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# tunnel seem endless by hiding its endpoint in darkness. Fog in panda works by
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# coloring objects based on their distance from the camera. Fog is not a 3D
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# volume object like real world fog.
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# With the right settings, Fog in panda can mimic the appearence of real world # fog.
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#
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# The tunnel and texture was originally created by Vamsi Bandaru and Victoria
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# Webb for the Entertainment Technology Center class Building Virtual Worlds
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from direct.showbase.ShowBase import ShowBase
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from panda3d.core import Fog
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from panda3d.core import TextNode
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from direct.gui.OnscreenText import OnscreenText
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from direct.showbase.DirectObject import DirectObject
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from direct.interval.MetaInterval import Sequence
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from direct.interval.LerpInterval import LerpFunc
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from direct.interval.FunctionInterval import Func
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import sys
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# Global variables for the tunnel dimensions and speed of travel
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TUNNEL_SEGMENT_LENGTH = 50
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TUNNEL_TIME = 2 # Amount of time for one segment to travel the
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# distance of TUNNEL_SEGMENT_LENGTH
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class FogDemo(ShowBase):
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# Macro-like function used to reduce the amount to code needed to create the
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# on screen instructions
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def genLabelText(self, i, text):
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return OnscreenText(text=text, parent=base.a2dTopLeft, scale=.05,
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pos=(0.06, -.065 * i), fg=(1, 1, 1, 1),
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align=TextNode.ALeft)
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def __init__(self):
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# Initialize the ShowBase class from which we inherit, which will
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# create a window and set up everything we need for rendering into it.
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ShowBase.__init__(self)
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# Standard initialization stuff
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# Standard title that's on screen in every tutorial
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self.title = OnscreenText(text="Panda3D: Tutorial - Fog", style=1,
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fg=(1, 1, 1, 1), shadow=(0, 0, 0, .5), parent=base.a2dBottomRight,
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align=TextNode.ARight, pos=(-0.1, 0.1), scale=.08)
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# Code to generate the on screen instructions
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self.escapeEventText = self.genLabelText(1, "ESC: Quit")
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self.pkeyEventText = self.genLabelText(2, "[P]: Pause")
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self.tkeyEventText = self.genLabelText(3, "[T]: Toggle Fog")
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self.dkeyEventText = self.genLabelText(4, "[D]: Make fog color black")
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self.sdkeyEventText = self.genLabelText(5, "[SHIFT+D]: Make background color black")
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self.rkeyEventText = self.genLabelText(6, "[R]: Make fog color red")
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self.srkeyEventText = self.genLabelText(7, "[SHIFT+R]: Make background color red")
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self.bkeyEventText = self.genLabelText(8, "[B]: Make fog color blue")
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self.sbkeyEventText = self.genLabelText(9, "[SHIFT+B]: Make background color blue")
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self.gkeyEventText = self.genLabelText(10, "[G]: Make fog color green")
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self.sgkeyEventText = self.genLabelText(11, "[SHIFT+G]: Make background color green")
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self.lkeyEventText = self.genLabelText(12, "[L]: Make fog color light grey")
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self.slkeyEventText = self.genLabelText(13, "[SHIFT+L]: Make background color light grey")
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self.pluskeyEventText = self.genLabelText(14, "[+]: Increase fog density")
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self.minuskeyEventText = self.genLabelText(15, "[-]: Decrease fog density")
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# disable mouse control so that we can place the camera
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base.disableMouse()
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camera.setPosHpr(0, 0, 10, 0, -90, 0)
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base.setBackgroundColor(0, 0, 0) # set the background color to black
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# World specific-code
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# Create an instance of fog called 'distanceFog'.
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#'distanceFog' is just a name for our fog, not a specific type of fog.
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self.fog = Fog('distanceFog')
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# Set the initial color of our fog to black.
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self.fog.setColor(0, 0, 0)
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# Set the density/falloff of the fog. The range is 0-1.
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# The higher the numer, the "bigger" the fog effect.
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self.fog.setExpDensity(.08)
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# We will set fog on render which means that everything in our scene will
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# be affected by fog. Alternatively, you could only set fog on a specific
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# object/node and only it and the nodes below it would be affected by
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# the fog.
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render.setFog(self.fog)
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# Define the keyboard input
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# Escape closes the demo
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self.accept('escape', sys.exit)
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# Handle pausing the tunnel
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self.accept('p', self.handlePause)
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# Handle turning the fog on and off
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self.accept('t', toggleFog, [render, self.fog])
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# Sets keys to set the fog to various colors
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self.accept('r', self.fog.setColor, [1, 0, 0])
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self.accept('g', self.fog.setColor, [0, 1, 0])
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self.accept('b', self.fog.setColor, [0, 0, 1])
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self.accept('l', self.fog.setColor, [.7, .7, .7])
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self.accept('d', self.fog.setColor, [0, 0, 0])
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# Sets keys to change the background colors
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self.accept('shift-r', base.setBackgroundColor, [1, 0, 0])
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self.accept('shift-g', base.setBackgroundColor, [0, 1, 0])
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self.accept('shift-b', base.setBackgroundColor, [0, 0, 1])
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self.accept('shift-l', base.setBackgroundColor, [.7, .7, .7])
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self.accept('shift-d', base.setBackgroundColor, [0, 0, 0])
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# Increases the fog density when "+" key is pressed
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self.accept('+', self.addFogDensity, [.01])
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# This is to handle the other "+" key (it's over = on the keyboard)
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self.accept('=', self.addFogDensity, [.01])
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self.accept('shift-=', self.addFogDensity, [.01])
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# Decreases the fog density when the "-" key is pressed
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self.accept('-', self.addFogDensity, [-.01])
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# Load the tunel and start the tunnel
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self.initTunnel()
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self.contTunnel()
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# This function will change the fog density by the amount passed into it
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# This function is needed so that it can look up the current value and
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# change it when the key is pressed. If you wanted to bind a key to set it
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# at a given value you could call self.fog.setExpDensity directly
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def addFogDensity(self, change):
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# The min() statement makes sure the density is never over 1
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# The max() statement makes sure the density is never below 0
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self.fog.setExpDensity(
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min(1, max(0, self.fog.getExpDensity() + change)))
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# Code to initialize the tunnel
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def initTunnel(self):
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self.tunnel = [None] * 4
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for x in range(4):
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# Load a copy of the tunnel
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self.tunnel[x] = loader.loadModel('models/tunnel')
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# The front segment needs to be attached to render
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if x == 0:
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self.tunnel[x].reparentTo(render)
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# The rest of the segments parent to the previous one, so that by moving
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# the front segement, the entire tunnel is moved
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else:
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self.tunnel[x].reparentTo(self.tunnel[x - 1])
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# We have to offset each segment by its length so that they stack onto
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# each other. Otherwise, they would all occupy the same space.
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self.tunnel[x].setPos(0, 0, -TUNNEL_SEGMENT_LENGTH)
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# Now we have a tunnel consisting of 4 repeating segments with a
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# hierarchy like this:
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# render<-tunnel[0]<-tunnel[1]<-tunnel[2]<-tunnel[3]
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# This function is called to snap the front of the tunnel to the back
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# to simulate traveling through it
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def contTunnel(self):
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# This line uses slices to take the front of the list and put it on the
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# back. For more information on slices check the Python manual
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self.tunnel = self.tunnel[1:] + self.tunnel[0:1]
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# Set the front segment (which was at TUNNEL_SEGMENT_LENGTH) to 0, which
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# is where the previous segment started
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self.tunnel[0].setZ(0)
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# Reparent the front to render to preserve the hierarchy outlined above
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self.tunnel[0].reparentTo(render)
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# Set the scale to be apropriate (since attributes like scale are
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# inherited, the rest of the segments have a scale of 1)
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self.tunnel[0].setScale(.155, .155, .305)
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# Set the new back to the values that the rest of teh segments have
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self.tunnel[3].reparentTo(self.tunnel[2])
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self.tunnel[3].setZ(-TUNNEL_SEGMENT_LENGTH)
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self.tunnel[3].setScale(1)
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# Set up the tunnel to move one segment and then call contTunnel again
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# to make the tunnel move infinitely
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self.tunnelMove = Sequence(
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LerpFunc(self.tunnel[0].setZ,
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duration=TUNNEL_TIME,
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fromData=0,
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toData=TUNNEL_SEGMENT_LENGTH * .305),
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Func(self.contTunnel)
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)
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self.tunnelMove.start()
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# This function calls toggle interval to pause or unpause the tunnel.
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# Like addFogDensity, toggleInterval could not be passed directly in the
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# accept command since the value of self.tunnelMove changes whenever
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#self.contTunnel is called
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def handlePause(self):
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toggleInterval(self.tunnelMove)
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# End Class World
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# This function will toggle any interval passed to it between playing and
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# paused
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def toggleInterval(interval):
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if interval.isPlaying():
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interval.pause()
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else:
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interval.resume()
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# This function will toggle fog on a node
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def toggleFog(node, fog):
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# If the fog attached to the node is equal to the one we passed in, then
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# fog is on and we should clear it
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if node.getFog() == fog:
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node.clearFog()
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# Otherwise fog is not set so we should set it
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else:
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node.setFog(fog)
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demo = FogDemo()
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demo.run()
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