278 lines
12 KiB
Python
278 lines
12 KiB
Python
#!/usr/bin/env python
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# Author: Shao Zhang and Phil Saltzman
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# Models: Eddie Canaan
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# Last Updated: 2015-03-13
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#
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# This tutorial shows how to determine what objects the mouse is pointing to
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# We do this using a collision ray that extends from the mouse position
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# and points straight into the scene, and see what it collides with. We pick
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# the object with the closest collision
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from direct.showbase.ShowBase import ShowBase
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from panda3d.core import CollisionTraverser, CollisionNode
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from panda3d.core import CollisionHandlerQueue, CollisionRay
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from panda3d.core import AmbientLight, DirectionalLight, LightAttrib
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from panda3d.core import TextNode
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from panda3d.core import LPoint3, LVector3, BitMask32
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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.task.Task import Task
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import sys
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# First we define some constants for the colors
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BLACK = (0, 0, 0, 1)
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WHITE = (1, 1, 1, 1)
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HIGHLIGHT = (0, 1, 1, 1)
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PIECEBLACK = (.15, .15, .15, 1)
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# Now we define some helper functions that we will need later
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# This function, given a line (vector plus origin point) and a desired z value,
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# will give us the point on the line where the desired z value is what we want.
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# This is how we know where to position an object in 3D space based on a 2D mouse
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# position. It also assumes that we are dragging in the XY plane.
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#
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# This is derived from the mathematical of a plane, solved for a given point
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def PointAtZ(z, point, vec):
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return point + vec * ((z - point.getZ()) / vec.getZ())
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# A handy little function for getting the proper position for a given square1
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def SquarePos(i):
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return LPoint3((i % 8) - 3.5, int(i // 8) - 3.5, 0)
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# Helper function for determining whether a square should be white or black
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# The modulo operations (%) generate the every-other pattern of a chess-board
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def SquareColor(i):
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if (i + ((i // 8) % 2)) % 2:
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return BLACK
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else:
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return WHITE
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class ChessboardDemo(ShowBase):
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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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# This code puts the standard title and instruction text on screen
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self.title = OnscreenText(text="Panda3D: Tutorial - Mouse Picking",
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style=1, fg=(1, 1, 1, 1), shadow=(0, 0, 0, 1),
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pos=(0.8, -0.95), scale = .07)
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self.escapeEvent = OnscreenText(
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text="ESC: Quit", parent=base.a2dTopLeft,
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style=1, fg=(1, 1, 1, 1), pos=(0.06, -0.1),
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align=TextNode.ALeft, scale = .05)
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self.mouse1Event = OnscreenText(
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text="Left-click and drag: Pick up and drag piece",
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parent=base.a2dTopLeft, align=TextNode.ALeft,
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style=1, fg=(1, 1, 1, 1), pos=(0.06, -0.16), scale=.05)
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self.accept('escape', sys.exit) # Escape quits
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self.disableMouse() # Disble mouse camera control
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camera.setPosHpr(0, -12, 8, 0, -35, 0) # Set the camera
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self.setupLights() # Setup default lighting
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# Since we are using collision detection to do picking, we set it up like
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# any other collision detection system with a traverser and a handler
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self.picker = CollisionTraverser() # Make a traverser
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self.pq = CollisionHandlerQueue() # Make a handler
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# Make a collision node for our picker ray
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self.pickerNode = CollisionNode('mouseRay')
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# Attach that node to the camera since the ray will need to be positioned
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# relative to it
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self.pickerNP = camera.attachNewNode(self.pickerNode)
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# Everything to be picked will use bit 1. This way if we were doing other
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# collision we could separate it
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self.pickerNode.setFromCollideMask(BitMask32.bit(1))
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self.pickerRay = CollisionRay() # Make our ray
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# Add it to the collision node
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self.pickerNode.addSolid(self.pickerRay)
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# Register the ray as something that can cause collisions
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self.picker.addCollider(self.pickerNP, self.pq)
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# self.picker.showCollisions(render)
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# Now we create the chess board and its pieces
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# We will attach all of the squares to their own root. This way we can do the
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# collision pass just on the squares and save the time of checking the rest
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# of the scene
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self.squareRoot = render.attachNewNode("squareRoot")
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# For each square
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self.squares = [None for i in range(64)]
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self.pieces = [None for i in range(64)]
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for i in range(64):
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# Load, parent, color, and position the model (a single square
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# polygon)
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self.squares[i] = loader.loadModel("models/square")
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self.squares[i].reparentTo(self.squareRoot)
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self.squares[i].setPos(SquarePos(i))
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self.squares[i].setColor(SquareColor(i))
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# Set the model itself to be collideable with the ray. If this model was
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# any more complex than a single polygon, you should set up a collision
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# sphere around it instead. But for single polygons this works
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# fine.
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self.squares[i].find("**/polygon").node().setIntoCollideMask(
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BitMask32.bit(1))
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# Set a tag on the square's node so we can look up what square this is
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# later during the collision pass
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self.squares[i].find("**/polygon").node().setTag('square', str(i))
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# We will use this variable as a pointer to whatever piece is currently
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# in this square
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# The order of pieces on a chessboard from white's perspective. This list
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# contains the constructor functions for the piece classes defined
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# below
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pieceOrder = (Rook, Knight, Bishop, Queen, King, Bishop, Knight, Rook)
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for i in range(8, 16):
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# Load the white pawns
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self.pieces[i] = Pawn(i, WHITE)
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for i in range(48, 56):
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# load the black pawns
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self.pieces[i] = Pawn(i, PIECEBLACK)
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for i in range(8):
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# Load the special pieces for the front row and color them white
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self.pieces[i] = pieceOrder[i](i, WHITE)
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# Load the special pieces for the back row and color them black
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self.pieces[i + 56] = pieceOrder[i](i + 56, PIECEBLACK)
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# This will represent the index of the currently highlited square
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self.hiSq = False
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# This wil represent the index of the square where currently dragged piece
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# was grabbed from
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self.dragging = False
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# Start the task that handles the picking
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self.mouseTask = taskMgr.add(self.mouseTask, 'mouseTask')
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self.accept("mouse1", self.grabPiece) # left-click grabs a piece
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self.accept("mouse1-up", self.releasePiece) # releasing places it
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# This function swaps the positions of two pieces
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def swapPieces(self, fr, to):
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temp = self.pieces[fr]
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self.pieces[fr] = self.pieces[to]
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self.pieces[to] = temp
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if self.pieces[fr]:
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self.pieces[fr].square = fr
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self.pieces[fr].obj.setPos(SquarePos(fr))
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if self.pieces[to]:
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self.pieces[to].square = to
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self.pieces[to].obj.setPos(SquarePos(to))
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def mouseTask(self, task):
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# This task deals with the highlighting and dragging based on the mouse
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# First, clear the current highlight
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if self.hiSq is not False:
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self.squares[self.hiSq].setColor(SquareColor(self.hiSq))
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self.hiSq = False
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# Check to see if we can access the mouse. We need it to do anything
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# else
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if self.mouseWatcherNode.hasMouse():
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# get the mouse position
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mpos = self.mouseWatcherNode.getMouse()
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# Set the position of the ray based on the mouse position
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self.pickerRay.setFromLens(self.camNode, mpos.getX(), mpos.getY())
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# If we are dragging something, set the position of the object
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# to be at the appropriate point over the plane of the board
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if self.dragging is not False:
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# Gets the point described by pickerRay.getOrigin(), which is relative to
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# camera, relative instead to render
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nearPoint = render.getRelativePoint(
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camera, self.pickerRay.getOrigin())
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# Same thing with the direction of the ray
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nearVec = render.getRelativeVector(
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camera, self.pickerRay.getDirection())
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self.pieces[self.dragging].obj.setPos(
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PointAtZ(.5, nearPoint, nearVec))
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# Do the actual collision pass (Do it only on the squares for
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# efficiency purposes)
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self.picker.traverse(self.squareRoot)
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if self.pq.getNumEntries() > 0:
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# if we have hit something, sort the hits so that the closest
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# is first, and highlight that node
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self.pq.sortEntries()
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i = int(self.pq.getEntry(0).getIntoNode().getTag('square'))
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# Set the highlight on the picked square
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self.squares[i].setColor(HIGHLIGHT)
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self.hiSq = i
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return Task.cont
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def grabPiece(self):
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# If a square is highlighted and it has a piece, set it to dragging
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# mode
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if self.hiSq is not False and self.pieces[self.hiSq]:
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self.dragging = self.hiSq
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self.hiSq = False
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def releasePiece(self):
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# Letting go of a piece. If we are not on a square, return it to its original
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# position. Otherwise, swap it with the piece in the new square
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# Make sure we really are dragging something
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if self.dragging is not False:
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# We have let go of the piece, but we are not on a square
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if self.hiSq is False:
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self.pieces[self.dragging].obj.setPos(
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SquarePos(self.dragging))
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else:
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# Otherwise, swap the pieces
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self.swapPieces(self.dragging, self.hiSq)
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# We are no longer dragging anything
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self.dragging = False
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def setupLights(self): # This function sets up some default lighting
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ambientLight = AmbientLight("ambientLight")
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ambientLight.setColor((.8, .8, .8, 1))
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directionalLight = DirectionalLight("directionalLight")
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directionalLight.setDirection(LVector3(0, 45, -45))
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directionalLight.setColor((0.2, 0.2, 0.2, 1))
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render.setLight(render.attachNewNode(directionalLight))
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render.setLight(render.attachNewNode(ambientLight))
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# Class for a piece. This just handles loading the model and setting initial
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# position and color
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class Piece(object):
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def __init__(self, square, color):
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self.obj = loader.loadModel(self.model)
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self.obj.reparentTo(render)
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self.obj.setColor(color)
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self.obj.setPos(SquarePos(square))
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# Classes for each type of chess piece
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# Obviously, we could have done this by just passing a string to Piece's init.
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# But if you wanted to make rules for how the pieces move, a good place to start
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# would be to make an isValidMove(toSquare) method for each piece type
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# and then check if the destination square is acceptible during ReleasePiece
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class Pawn(Piece):
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model = "models/pawn"
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class King(Piece):
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model = "models/king"
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class Queen(Piece):
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model = "models/queen"
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class Bishop(Piece):
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model = "models/bishop"
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class Knight(Piece):
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model = "models/knight"
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class Rook(Piece):
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model = "models/rook"
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# Do the main initialization and start 3D rendering
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demo = ChessboardDemo()
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demo.run()
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