#Author: Kwasi Mensah
#Date: 7/11/2005
#
# This is a tutorial to show some of the more advanced things
# you can do with Cg. Specifically, with Non Photo Realistic
# effects like Toon Shading. It also shows how to implement
# multiple buffers in Panda.


import direct.directbase.DirectStart
from pandac.PandaModules import PandaNode,LightNode,TextNode
from pandac.PandaModules import Filename
from pandac.PandaModules import NodePath
from pandac.PandaModules import Shader
from pandac.PandaModules import Point3,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
from direct.showbase.BufferViewer import BufferViewer
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 ToonMaker(DirectObject):
    def __init__(self):
	base.disableMouse()
	camera.setPos(0, -50, 0)
        
	# Post the instructions.
	self.title = addTitle("Panda3D: Tutorial - Toon Shading with Normals-Based Inking")
	self.inst1 = addInstructions(0.95,"ESC: Quit")
	self.inst2 = addInstructions(0.90,"Up/Down: Increase/Decrease Line Thickness")
	self.inst3 = addInstructions(0.85,"Left/Right: Decrease/Increase Line Darkness")
	self.inst4 = addInstructions(0.80,"V: View the render-to-texture results")

        # This shader's job is to render the model with discrete lighting
        # levels.  The lighting calculations built into the shader assume
        # a single nonattenuating point light.

        tempnode = NodePath(PandaNode("temp node"))
        tempnode.setShader(Shader.load(MYDIR+"/lightingGen.sha"))
        base.cam.node().setInitialState(tempnode.getState())
        
        # This is the object that represents the single "light", as far
        # the shader is concerned.  It's not a real Panda3D LightNode, but
        # the shader doesn't care about that.

        light = render.attachNewNode("light")
        light.setPos(30,-50,0)
                
        # this call puts the light's nodepath into the render state.
        # this enables the shader to access this light by name.

        render.setShaderInput("light", light)

        # The "normals buffer" will contain a picture of the model colorized
        # so that the color of the model is a representation of the model's
        # normal at that point.

        normalsBuffer=base.win.makeTextureBuffer("normalsBuffer", 0, 0)
        normalsBuffer.setClearColor(Vec4(0.5,0.5,0.5,1))
        self.normalsBuffer=normalsBuffer
        normalsCamera=base.makeCamera(normalsBuffer, aspectRatio=base.getAspectRatio())
        normalsCamera.node().setScene(render)
        tempnode = NodePath(PandaNode("temp node"))
        tempnode.setShader(Shader.load(MYDIR+"/normalGen.sha"))
        normalsCamera.node().setInitialState(tempnode.getState())

        #what we actually do to put edges on screen is apply them as a texture to 
        #a transparent screen-fitted card

        drawnScene=normalsBuffer.getTextureCard()
        drawnScene.setTransparency(1)
        drawnScene.setColor(1,1,1,0)
        drawnScene.reparentTo(render2d)
        self.drawnScene = drawnScene

        # this shader accepts, as input, the picture from the normals buffer.
        # it compares each adjacent pixel, looking for discontinuities.
        # wherever a discontinuity exists, it emits black ink.
                
        self.separation = 0.001
        self.cutoff = 0.3
        inkGen=Shader.load(MYDIR+"/inkGen.sha")
        drawnScene.setShader(inkGen)
        drawnScene.setShaderInput("separation", Vec4(self.separation,0,self.separation,0));
        drawnScene.setShaderInput("cutoff", Vec4(self.cutoff,self.cutoff,self.cutoff,self.cutoff));
        
        # Panda contains a built-in viewer that lets you view the results of
        # your render-to-texture operations.  This code configures the viewer.

        self.accept("v", base.bufferViewer.toggleEnable)
        self.accept("V", base.bufferViewer.toggleEnable)
        base.bufferViewer.setPosition("llcorner")

	# Load a dragon model and animate it.

	self.character=Actor()
	self.character.loadModel(MYDIR+'/nik-dragon')
	self.character.reparentTo(render)
	self.character.loadAnims({'win': MYDIR+'/nik-dragon'})
	self.character.loop('win')
	self.character.hprInterval(15, Point3(360, 0,0)).loop()

        # these allow you to change cartooning parameters in realtime

        self.accept("escape", sys.exit, [0])
        self.accept("arrow_up", self.increaseSeparation)
        self.accept("arrow_down", self.decreaseSeparation)
        self.accept("arrow_left", self.increaseCutoff)
        self.accept("arrow_right", self.decreaseCutoff)
        
    def increaseSeparation(self):
        self.separation = self.separation * 1.11111111;
        print self.separation
        self.drawnScene.setShaderInput("separation", Vec4(self.separation,0,self.separation,0));
        
    def decreaseSeparation(self):
        self.separation = self.separation * 0.90000000;
        print self.separation
        self.drawnScene.setShaderInput("separation", Vec4(self.separation,0,self.separation,0));
        
    def increaseCutoff(self):
        self.cutoff = self.cutoff * 1.11111111;
        print self.cutoff
        self.drawnScene.setShaderInput("cutoff", Vec4(self.cutoff,self.cutoff,self.cutoff,self.cutoff));
        
    def decreaseCutoff(self):
        self.cutoff = self.cutoff * 0.90000000;
        print self.cutoff
        self.drawnScene.setShaderInput("cutoff", Vec4(self.cutoff,self.cutoff,self.cutoff,self.cutoff));
        
if (base.win.getGsg().getSupportsBasicShaders()):
    t=ToonMaker()
else:
    t=addTitle("Toon Shader: Video driver reports that shaders are not supported.")

run()

