interface/glcanvas.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        glcanvas.h
   3 // Purpose:     interface of wxGLContext
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxGLContext
  11     @wxheader{glcanvas.h}
  12
  13     An instance of a wxGLContext represents the state of an OpenGL state machine
  14     and the connection between OpenGL and the system.
  15
  16     The OpenGL state includes everything that can be set with the OpenGL API:
  17     colors, rendering variables, display lists, texture objects, etc.
  18     Although it is possible to have multiple rendering contexts share display lists
  19     in order to save resources,
  20     this method is hardly used today any more, because display lists are only a
  21     tiny fraction of the overall state.
  22
  23     Therefore, one rendering context is usually used with or bound to multiple
  24     output windows in turn,
  25     so that the application has access to the complete and identical state while
  26     rendering into each window.
  27
  28     Binding (making current) a rendering context with another instance of a
  29     wxGLCanvas however works only
  30     if the other wxGLCanvas was created with the same attributes as the wxGLCanvas
  31     from which the wxGLContext
  32     was initialized. (This applies to sharing display lists among contexts
  33     analogously.)
  34
  35     Note that some wxGLContext features are extremely platform-specific - its best
  36     to check your native platform's glcanvas header (on windows include/wx/msw/glcanvas.h) to see what features your native platform provides.
  37
  38     @library{wxgl}
  39     @category{gl}
  40
  41     @see wxGLCanvas
  42 */
  43 class wxGLContext : public wxObject
  44 {
  45 public:
  46     /**
  47         Constructor.
  48
  49         @param win
  50             The canvas that is used to initialize this context. This parameter is
  51         needed only temporarily,
  52             and the caller may do anything with it (e.g. destroy the window) after the
  53         constructor returned.
  54             It will be possible to bind (make current) this context to any other
  55         wxGLCanvas that has been created
  56             with equivalent attributes as win.
  57         @param other
  58             Context to share display lists with or @NULL (the default) for no sharing.
  59     */
  60     wxGLContext(wxGLCanvas* win, const wxGLContext* other = NULL);
  61
  62     /**
  63         Makes the OpenGL state that is represented by this rendering context current
  64         with the wxGLCanvas @e win.
  65         Note that @a win can be a different wxGLCanvas window than the one that was
  66         passed to the constructor of this rendering context.
  67         If  @e RC  is an object of type wxGLContext, the statements @e
  68         RC.SetCurrent(win); and @e win.SetCurrent(RC); are equivalent,
  69         see wxGLCanvas::SetCurrent.
  70     */
  71     void SetCurrent(const wxGLCanvas& win);
  72 };
  73
  74
  75
  76 /**
  77     @class wxGLCanvas
  78     @wxheader{glcanvas.h}
  79
  80     wxGLCanvas is a class for displaying OpenGL graphics. It is always used in
  81     conjunction with wxGLContext as the context can only be
  82     be made current (i.e. active for the OpenGL commands) when it is associated to
  83     a wxGLCanvas.
  84
  85     More precisely, you first need to create a wxGLCanvas window and then create an
  86     instance of a wxGLContext that is initialized with this
  87     wxGLCanvas and then later use either wxGLCanvas::SetCurrent
  88     with the instance of the wxGLContext or
  89     wxGLContext::SetCurrent with the instance of
  90     the wxGLCanvas (which might be not the same as was used
  91     for the creation of the context) to bind the OpenGL state that is represented
  92     by the rendering context to the canvas, and then finally call
  93     wxGLCanvas::SwapBuffers to swap the buffers of
  94     the OpenGL canvas and thus show your current output.
  95
  96     Notice that previous versions of wxWidgets used to implicitly create a
  97     wxGLContext inside wxGLCanvas itself. This is still supported in the current
  98     version but is deprecated now and will be removed in the future, please update
  99     your code to create the rendering contexts explicitly.
 100
 101     To set up the attributes for the canvas (number of bits for the depth buffer,
 102     number of bits for the stencil buffer and so on) you should set up the correct
 103     values of
 104     the @e attribList parameter. The values that should be set up and their
 105     meanings will be described below.
 106
 107     Notice that OpenGL is not enabled by default. To switch it on, you need to edit
 108     setup.h under Windows and set @c wxUSE_GLCANVAS to 1 (you may also need
 109     to have to add @c opengl32.lib and @c glu32.lib to the list of libraries
 110     your program is linked with). On Unix, pass @c --with-opengl to configure.
 111
 112     @library{wxgl}
 113     @category{gl}
 114
 115     @see wxGLContext
 116 */
 117 class wxGLCanvas : public wxWindow
 118 {
 119 public:
 120     /**
 121         Creates a window with the given parameters. Notice that you need to create and
 122         use a wxGLContext to output to this window.
 123         If
 124
 125         @param attribList is not specified, double buffered RGBA mode is used.
 126
 127         parent
 128             Pointer to a parent window.
 129         @param id
 130             Window identifier. If -1, will automatically create an identifier.
 131         @param pos
 132             Window position. wxDefaultPosition is (-1, -1) which indicates that
 133         wxWidgets
 134             should generate a default position for the window.
 135         @param size
 136             Window size. wxDefaultSize is (-1, -1) which indicates that wxWidgets should
 137             generate a default size for the window. If no suitable size can be found,
 138         the window will be sized to 20x20 pixels so that the window is visible but obviously not correctly sized.
 139         @param style
 140             Window style.
 141         @param name
 142             Window name.
 143         @param attribList
 144             Array of integers. With this parameter you can set the device context
 145         attributes associated to this window.
 146             This array is zero-terminated: it should be set up with constants described
 147         in the table above.
 148             If a constant should be followed by a value, put it in the next array
 149         position.
 150             For example, the WX_GL_DEPTH_SIZE should be followed by the value that
 151         indicates the number of
 152             bits for the depth buffer, so:
 153         @param palette
 154             Palette for indexed colour (i.e. non WX_GL_RGBA) mode.
 155             Ignored under most platforms.
 156     */
 157     wxGLCanvas(wxWindow* parent, wxWindowID id = wxID_ANY,
 158                const int* attribList = NULL,
 159                const wxPoint& pos = wxDefaultPosition,
 160                const wxSize& size = wxDefaultSize,
 161                long style = 0,
 162                const wxString& name = "GLCanvas",
 163                const wxPalette& palette = wxNullPalette);
 164
 165     /**
 166         Determines if a canvas having the specified attributes is available.
 167         Returns @true if attributes are supported.
 168
 169         @param attribList
 170             See attribList for wxGLCanvas().
 171     */
 172     static bool IsDisplaySupported(const int* attribList = NULL);
 173
 174     /**
 175         Sets the current colour for this window (using @c glcolor3f()), using the
 176         wxWidgets colour database to find a named colour.
 177     */
 178     void SetColour(const wxString& colour);
 179
 180     /**
 181         Makes the OpenGL state that is represented by the OpenGL rendering context
 182         @a context current, i.e. it will be used by all subsequent OpenGL calls.
 183         This is equivalent to wxGLContext::SetCurrent
 184         called with this window as parameter.
 185         Note that this function may only be called when the window is shown on screen,
 186         in particular it can't usually be called from the constructor as the window
 187         isn't yet shown at this moment.
 188         Returns @false if an error occurred.
 189     */
 190     bool SetCurrent(const wxGLContext context);
 191
 192     /**
 193         Swaps the double-buffer of this window, making the back-buffer the front-buffer
 194         and vice versa,
 195         so that the output of the previous OpenGL commands is displayed on the window.
 196         Returns @false if an error occurred.
 197     */
 198     bool SwapBuffers();
 199 };
 200