#
# Normal mapping is a way of making polygonal surfaces look
# less flat.  Another word for normal mapping is "bump mapping."
#
# This is a tutorial to show how to do normal mapping
# in panda3d using Cg.  This is probably the simplest possible
# version of normal mapping: just one point light, one ambient
# light, and no shadows.

import direct.directbase.DirectStart
from pandac.PandaModules import WindowProperties
from pandac.PandaModules import Filename,Shader
from pandac.PandaModules import AmbientLight,PointLight
from pandac.PandaModules import TextNode
from pandac.PandaModules import Point3,Vec3,Vec4
from direct.task.Task import Task
from direct.actor.Actor import Actor
from direct.gui.OnscreenText import OnscreenText
from direct.showbase.DirectObject import DirectObject
import sys,os

# Figure out what directory this program is in.
MYDIR=os.path.abspath(sys.path[0])
MYDIR=Filename.fromOsSpecific(MYDIR).getFullpath()

# Function to put instructions on the screen.
def addInstructions(pos, msg):
    return OnscreenText(text=msg, style=1, fg=(1,1,1,1),
			pos=(-1.3, pos), align=TextNode.ALeft, scale = .05)

# Function to put title on the screen.
def addTitle(text):
    return OnscreenText(text=text, style=1, fg=(1,1,1,1),
	                pos=(1.3,-0.95), align=TextNode.ARight, scale = .07)


class NormalMapDemo(DirectObject):

    def __init__(self):

	# Post the instructions
	self.title = addTitle("Panda3D: Tutorial - Normal Mapping (aka Bump Mapping)")
	self.inst1 = addInstructions(0.95, "Press ESC to exit")
	self.inst2 = addInstructions(0.90, "Move mouse to rotate camera")
	self.inst3 = addInstructions(0.85, "Left mouse button: Move forwards")
	self.inst4 = addInstructions(0.80, "Right mouse button: Move backwards")
	self.inst5 = addInstructions(0.75, "Enter: Turn normal maps Off")

        # Load the 'abstract room' model.  This is a model of an
        # empty room containing a pillar, a pyramid, and a bunch
        # of exaggeratedly bumpy textures.

        self.room = loader.loadModel(MYDIR+"/models/abstractroom")
        self.room.reparentTo(render)

        # Make the mouse invisible, turn off normal mouse controls
        base.disableMouse()
        props = WindowProperties()
        props.setCursorHidden(True)
        base.win.requestProperties(props)

        # Set the current viewing target
        self.focus = Vec3(48,0,25)
        self.heading = 180
        self.pitch = 0
        self.mousex = 0
        self.mousey = 0
        self.last = 0
        self.mousebtn = [0,0,0]

        # Start the camera control task:
        taskMgr.add(self.controlCamera, "camera-task")
        self.accept("escape", sys.exit, [0])
        self.accept("mouse1", self.setMouseBtn, [0, 1])
        self.accept("mouse1-up", self.setMouseBtn, [0, 0])
        self.accept("mouse2", self.setMouseBtn, [1, 1])
        self.accept("mouse2-up", self.setMouseBtn, [1, 0])
        self.accept("mouse3", self.setMouseBtn, [2, 1])
        self.accept("mouse3-up", self.setMouseBtn, [2, 0])
        self.accept("enter", self.toggleShader)
        self.accept("j", self.rotateLight, [-1])
        self.accept("k", self.rotateLight, [1])
        self.accept("arrow_left", self.rotateCam, [-1])
        self.accept("arrow_right", self.rotateCam, [1])

        # Add a light to the scene.
        self.lightpivot = render.attachNewNode("lightpivot")
        self.lightpivot.setPos(0,0,25)
	self.lightpivot.hprInterval(10,Point3(360,0,0)).loop()
        plight = PointLight('plight')
        plight.setColor(Vec4(1, 1, 1, 1))
        plight.setAttenuation(Vec3(0,0.05,0))
        plnp = self.lightpivot.attachNewNode(plight.upcastToPandaNode())
        plnp.setPos(45, 0, 0)
        self.room.setLight(plnp)
        self.room.setShaderInput("light", plnp)
        
        # Add an ambient light
        alight = AmbientLight('alight')
        alight.setColor(Vec4(0.2, 0.2, 0.2, 1))
        alnp = render.attachNewNode(alight.upcastToPandaNode())
        self.room.setLight(alnp)

        # create a sphere to denote the light
        sphere = loader.loadModel("misc/sphere")
        sphere.reparentTo(plnp)

        # load and apply the shader.
        self.shader = Shader.load(MYDIR+"/bumpMapper.sha")
        self.room.setShader(self.shader)
        self.shaderenable = 1
        
    def setMouseBtn(self, btn, value):
        self.mousebtn[btn] = value

    def rotateLight(self, offset):
        self.lightpivot.setH(self.lightpivot.getH()+offset*20)

    def rotateCam(self, offset):
        self.heading = self.heading - offset*10

    def toggleShader(self):
        self.inst5.destroy()
        if (self.shaderenable):
            self.inst5 = addInstructions(0.75, "Enter: Turn normal maps On")
            self.shaderenable = 0
            self.room.setShaderOff()
        else:
            self.inst5 = addInstructions(0.75, "Enter: Turn normal maps Off")
            self.shaderenable = 1
            self.room.setShader(self.shader)

    def controlCamera(self, task):
        # figure out how much the mouse has moved (in pixels)
        md = base.win.getPointer(0)
        x = md.getX()
        y = md.getY()
        if base.win.movePointer(0, 100, 100):
            self.heading = self.heading - (x - 100)*0.2
            self.pitch = self.pitch - (y - 100)*0.2
        if (self.pitch < -45): self.pitch = -45
        if (self.pitch >  45): self.pitch =  45
        base.camera.setHpr(self.heading,self.pitch,0)
        dir = base.camera.getMat().getRow3(1)
        elapsed = task.time - self.last
        if (self.last == 0): elapsed = 0
        if (self.mousebtn[0]):
            self.focus = self.focus + dir * elapsed*30
        if (self.mousebtn[1]) or (self.mousebtn[2]):
            self.focus = self.focus - dir * elapsed*30
        base.camera.setPos(self.focus - (dir*5))
        if (base.camera.getX() < -49.0): base.camera.setX(-49)
        if (base.camera.getX() >  49.0): base.camera.setX( 49)
        if (base.camera.getY() < -49.0): base.camera.setY(-49)
        if (base.camera.getY() >  49.0): base.camera.setY( 49)
        if (base.camera.getZ() <   1.0): base.camera.setZ(  1)
        if (base.camera.getZ() >  49.0): base.camera.setZ( 49)
        self.focus = base.camera.getPos() + (dir*5)
        self.last = task.time
        return Task.cont


if (base.win.getGsg().getSupportsBasicShaders()):
    t=NormalMapDemo()
else:
    t=addTitle("Normal Map Demo: Video driver reports that shaders are not supported.")

run()

