/[escript]/trunk/pyvisi/py_src/light.py
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Contents of /trunk/pyvisi/py_src/light.py

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Revision 1148 - (show annotations)
Wed May 16 22:45:33 2007 UTC (14 years, 1 month ago) by jongui
File MIME type: text/x-python
File size: 3498 byte(s)
Added the updated files for pyvisi and removed some incorrect reference images.
1 """
2 @author: John NGUI
3 """
4
5 import vtk
6 from position import GlobalPosition
7 from constant import Viewport
8
9 class Light:
10 """
11 Class that defines a light. A light controls the lighting for the
12 rendered object and works in a similar way to L{Camera <camera.Camera>}.
13 """
14
15 # The SOUTH_WEST default viewport is used when there is only one viewport.
16 # This saves the user from specifying the viewport when there is only one.
17 def __init__(self, scene, viewport = Viewport.SOUTH_WEST):
18 """
19 Initialise the light.
20
21 @type scene: L{Scene <scene.Scene>} object
22 @param scene: Scene in which components are to be added to
23 @type viewport: L{Viewport <constant.Viewport>} constant
24 @param viewport: Viewport in which objects are to be rendered on
25 """
26
27 self.__scene = scene
28 self.__viewport = viewport
29 self.__vtk_light = vtk.vtkLight()
30
31 # Keeps track whether light has been modified.
32 self.__modified = True
33 # Keeps track whether the modification to the light was due to the
34 # instantiation. If it is, then __setupLight() method is called.
35 self.__initialization = True
36 self.__scene._addVisualizationModules(self)
37
38 def __setupLight(self):
39 """
40 Set up the light and associate it with the renderer.
41 """
42
43 self.__scene._addLight(self.__viewport, self.__vtk_light)
44
45 def setColor(self, color):
46 """
47 Set the light color.
48
49 @type color: L{Color <constant.Color>} constant
50 @param color: Light color
51 """
52
53 self.__vtk_light.SetColor(color)
54 self.__modified = True
55
56 def setFocalPoint(self, position):
57 """
58 Set the focal point of the light.
59
60 @type position: L{GlobalPosition <position.GlobalPosition>} object
61 @param position: Light focal point
62 """
63
64 self.__vtk_light.SetFocalPoint(position._getGlobalPosition())
65 self.__modified = True
66
67 def setPosition(self, position):
68 """
69 Set the position of the light.
70
71 @type position: L{GlobalPosition <position.GlobalPosition>} object
72 @param position: Light position
73 """
74
75 self.__vtk_light.SetPosition(position._getGlobalPosition())
76 self.__modified = True
77
78 # Elevation and azimuth is set to zero so that users do not
79 # have to change both at the same time.
80 def setAngle(self, elevation = 0, azimuth = 0):
81 """
82 An alternative to set the position and focal point of the light
83 by using the elevation and azimuth.
84
85 @type elevation: Number
86 @param elevation: Degree to rotate the light to the top and bottom
87 @type azimuth: Number
88 @param azimuth: Degree to rotate the light to the left and right
89 """
90
91 # NOTE: The elevation angle of light does not appear to suffer the same
92 # constraint as the elevation angle of camera where the elevation
93 # angle is constraint between 90/-90.
94 self.__vtk_light.SetDirectionAngle(elevation, azimuth)
95 self.__modified = True
96
97 def setIntensity(self, intensity):
98 """
99 Set the intensity (brightness) of the light.
100
101 @type intensity: Number
102 @param intensity: Intensity (brightness) of the light
103 """
104
105 self.__vtk_light.SetIntensity(intensity)
106 self.__modified = True
107
108 def _isModified(self):
109 """
110 Return whether the Light has been modified.
111
112 @rtype: Boolean
113 @return: True or False
114 """
115
116 if (self.__modified == True):
117 return True
118 else:
119 return False
120
121 def _render(self):
122 """
123 Render the light.
124 """
125
126 if(self._isModified() == True):
127 # Will only be true once only when the light is instantiated.
128 if(self.__initialization == True):
129 self.__setupLight()
130 self.__initialization == False
131
132 self.__isModified = False
133
134

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