class Canvas

# File examples/ruboids/ruboids/Canvas.rb, line 25
def initialize(parent = nil, name = '')
    super(parent)
    @grassObject = nil
end

# File examples/ruboids/ruboids/Canvas.rb, line 34
def initializeGL()
    ClearColor(0.4, 0.4, 1.0, 0.0) # Let OpenGL clear to light blue
    @grassObject = makeGrassObject()
    ShadeModel(FLAT)
end

# File examples/ruboids/ruboids/Canvas.rb, line 81
def makeGrassObject
    halfXSize = $PARAMS['world_width']
    halfYSize = $PARAMS['world_depth'] / 2
    halfZSize = $PARAMS['world_height']

    list = GenLists(1)
    NewList(list, COMPILE)
    LineWidth(2.0)
    Begin(QUADS)

    Color(GRASS_COLOR)
    # Counter-clockwise
    Vertex( halfXSize, -halfYSize,  halfZSize)
    Vertex(-halfXSize, -halfYSize,  halfZSize)
    Vertex(-halfXSize, -halfYSize, -halfZSize)
    Vertex( halfXSize, -halfYSize, -halfZSize)

    End()
    EndList()
    return list
end

# File examples/ruboids/ruboids/Canvas.rb, line 117
def mouseMoveEvent(e)
    return if @mouseLoc.nil?

    dx = dy = 0
    if e.x() != @mouseLoc.x()
        dx = e.x() - @mouseLoc.x() # move right increases dx
        @mouseLoc.setX(e.x())
    end
    if e.y() != @mouseLoc.y()
        dy = @mouseLoc.y() - e.y() # move up increases dy
        @mouseLoc.setY(e.y())
    end

    return if dx == 0 && dy == 0

    case @mouseDragAction
    when MDA_ZOOM
        return if (dy == 0)
        World.instance.camera.zoom += 0.1 * -dy
    when MDA_ROTATE
        break
    when MDA_CHANGE_FOCUS
        break
    end
    World.instance.setupTranslation()
end

# File examples/ruboids/ruboids/Canvas.rb, line 103
def mousePressEvent(e)
    @mouseLoc = e.pos()
    case e.button()
    when Qt::LeftButton
        @mouseDragAction = MDA_ZOOM
    when Qt::RightButton
        @mouseDragAction = MDA_ROTATE
    when Qt::MidButton
        @mouseDragAction = MDA_CHANGE_FOCUS
    end
end

# File examples/ruboids/ruboids/Canvas.rb, line 40
def paintGL()
    Enable(DEPTH_TEST)
    Clear(COLOR_BUFFER_BIT | DEPTH_BUFFER_BIT)

    MatrixMode(MODELVIEW)

    camera = World.instance.camera

    LoadIdentity()
    Rotate(camera.rotation.x, 1, 0, 0)
    Rotate(camera.rotation.y, 0, 1, 0)
    Rotate(camera.rotation.z, 0, 0, 1.0)
    Translate(-camera.position.x, -camera.position.y, -camera.position.z)
    Scale(camera.zoom, camera.zoom, camera.zoom)

    CallList(@grassObject)

    World.instance.clouds.each { | cloud | cloud.draw() }
    World.instance.flock.draw()
end

# File examples/ruboids/ruboids/Canvas.rb, line 62
    def resizeGL(w, h)
        Viewport(0, 0, w, h)
        MatrixMode(PROJECTION)
        LoadIdentity()

#          # left, right, bottom, top, front, back (focal_length)
        halfXSize = $PARAMS['world_width'] / 2 * 1.25
        halfYSize = $PARAMS['world_height'] / 2 * 1.25
        halfZSize = $PARAMS['world_depth'] / 2 * 1.25

#            Frustum(-halfXSize, halfXSize, -halfYSize, halfYSize,
#                  5, halfZSize * 2)

        Ortho(-halfXSize, halfXSize, -halfYSize, halfYSize,
              -halfZSize, halfZSize)

        MatrixMode(MODELVIEW)
    end

# File examples/ruboids/ruboids/Canvas.rb, line 30
def update
    updateGL()
end