root/src/widgets/Canvas.pym

Revision 1345:ff8ef9c6bbb7, 6.1 KB (checked in by Arc Riley <arcriley@…>, 14 months ago)

Happy New Year! (copyright string update)
Line 
1# PySoy widgets.Canvas class
2#
3# Copyright (C) 2006,2007,2008,2009 PySoy Group
4#
5#  This program is free software; you can redistribute it and/or modify
6#  it under the terms of the GNU Affero General Public License as published
7#  by the Free Software Foundation, either version 3 of the License, or
8#  (at your option) any later version.
9#
10#  This program is distributed in the hope that it will be useful,
11#  but WITHOUT ANY WARRANTY; without even the implied warranty of
12#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13#  GNU Affero General Public License for more details.
14#
15#  You should have received a copy of the GNU Affero General Public License
16#  along with this program; if not, see http://www.gnu.org/licenses
17#
18# $Id: Canvas.pym 1393 2008-12-31 23:51:25Z ArcRiley $
19
20cdef class Canvas (Widget) :
21  """
22  Renders a :class:`~soy.textures.Texture`.
23
24  Since :class:`~soy.textures.Texture`s can be any sort of bitmap, including text, images,
25  and video, adding a :class:`~soy.widgets.Canvas` to a :class:`~soy.Window` containing a video or
26  image before adding a :class:`~soy.widgets.Projector` will create a background.  The
27  :class:`~soy.widgets.Canvas` will be rendered, then the :class:`~soy.widgets.Projector` will render the
28  scene, overwriting the :class:`~soy.widgets.Canvas` where scene elements overlap.
29
30  Adding a :class:`~soy.widgets.Canvas` after a :class:`~soy.widgets.Projector` with a :class:`~soy.textures.Print` can also be
31  used to create a heads-up display.  The :class:`~soy.widgets.Projector` renders the
32  scene, then the :class:`~soy.widgets.Canvas` renders the :class:`~soy.widgets.Print` texture on top of the
33  :class:`~soy.scenes.Scene`, overwriting the overlapping scene regions.
34
35  Even more effects can be created by combining :class:`~soy.widgets.Canvas`es with the
36  different :class:`~soy.widgets.Container` subclasses.
37  """
38
39  ############################################################################
40  #
41  # Python functions
42  #
43 
44  def __cinit__(self, parent=None, margin=None, aspect=-1.0,
45                texture=None,
46                *args, **keywords) :
47    ######################################
48    #
49    # Pass arguments to properties
50    #
51    self.texture = texture
52    if aspect < 0.0 :
53      self._aspect = (<soy.textures.Texture> self._texture)._aspect
54    #
55    ######################################
56    #
57    # Static Vertex and Face Array
58    # 
59    #   self._verts[0] = (0,0) - no change needed
60    #   self._verts[1] = (1,0) - change X to 1.0
61    #   self._verts[2] = (1,1) - change both X and Y to 1.0
62    #   self._verts[3] = (0,1) - change Y to 1.0
63    #
64    #   Thus, these verts form a 1x1 square with 2 tris (A and B) :
65    #     3----2
66    #     | B/ |
67    #     | /A |
68    #     0----1
69    #
70    self._verts[1].px = 1.0
71    self._verts[1].tx = 1.0
72    self._verts[2].px = 1.0
73    self._verts[2].py = 1.0
74    self._verts[2].tx = 1.0
75    self._verts[2].ty = 1.0
76    self._verts[3].py = 1.0
77    self._verts[3].ty = 1.0
78    self._faces[0].a = 0
79    self._faces[0].b = 1
80    self._faces[0].c = 2
81    self._faces[1].a = 2
82    self._faces[1].b = 3
83    self._faces[1].c = 0
84    #
85    ######################################
86
87
88  ############################################################################
89  #
90  # C functions
91  #
92 
93  cdef void _render(self) :
94    cdef int _i
95    #
96    ######################################
97    #
98    # don't bother rendering w/o a texture
99    #
100    if self._texture is None :
101      return
102    #
103    ######################################
104    #
105    # Set the viewport to the current Widget position and size
106    #
107    gl.glViewport(self._xpos, self._ypos, self._width, self._height)
108    #
109    ######################################
110    #
111    # Reset the projection and modelview matrix, set ortho rendering
112    #
113    gl.glMatrixMode(gl.GL_PROJECTION)
114    gl.glLoadIdentity()
115    gl.glOrtho(0.0, 1.0, 0.0, 1.0, -1, 1)
116    gl.glMatrixMode(gl.GL_MODELVIEW)
117    gl.glLoadIdentity()
118    #
119    ######################################
120    #
121    # VBO-ONLY: Unbind buffers
122    #
123    if gl.GLEW_ARB_vertex_buffer_object :
124      gl.glBindBufferARB  (gl.GL_ELEMENT_ARRAY_BUFFER_ARB, 0)
125      gl.glBindBufferARB  (gl.GL_ARRAY_BUFFER_ARB, 0)
126    #
127    ######################################
128    #
129    # enable texture0
130    #
131    gl.glClientActiveTexture(gl.GL_TEXTURE0)
132    gl.glEnableClientState(gl.GL_TEXTURE_COORD_ARRAY)
133    self._texture._enable()
134    #
135    ######################################
136    #
137    # Enable blending if texture has an alpha channel (LA or RGBA)
138    #
139    if self._texture._chans & 1:
140      gl.glDisable(gl.GL_BLEND)
141    else:
142      gl.glEnable(gl.GL_BLEND)
143      gl.glBlendFunc(gl.GL_SRC_ALPHA, gl.GL_ONE_MINUS_SRC_ALPHA)
144    #
145    ######################################
146    #
147    # Set vertex, normal, and texcoord pointers and draw
148    #
149    gl.glVertexPointer  (3,  gl.GL_FLOAT, 48, &self._verts[0].px)
150    gl.glNormalPointer  (    gl.GL_FLOAT, 48, &self._verts[0].nx)
151    gl.glTexCoordPointer(3,  gl.GL_FLOAT, 48, &self._verts[0].tx)
152    gl.glDrawElements   (gl.GL_TRIANGLES, 6, gl.GL_UNSIGNED_SHORT,
153                         <unsigned short*> self._faces)
154    #
155    ######################################
156    #
157    # Disable blending when using alpha texture, disable texture, and return
158    #
159    if not self._texture._chans & 1 :
160      gl.glDisable(gl.GL_BLEND)
161    self._texture._disable()
162    #
163    ######################################
164
165
166  ############################################################################
167  #
168  # Properties
169  #
170 
171  property texture :
172    """
173    :class:`~soy.textures.Texture` rendered by this :class:`~soy.widgets.Canvas`.  Setting to None or
174    deleting it disables this Canvas.  This can be changed at any time
175    to change the :class:`~soy.textures.Texture` this :class:`~soy.widgets.Canvas` renders.
176    """
177
178    def __get__(self) :
179      if self._texture :
180        return self._texture
181      return None
182    def __set__(self, value) :
183      if isinstance(value, soy.textures.Texture) or value == None :   
184        self._texture = value
185      else :
186        raise TypeError('that is not a texture')
187    def __del__(self) :
188      self._texture = None
Note: See TracBrowser for help on using the browser.