interface/wx/glcanvas.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        glcanvas.h
   3 // Purpose:     interface of wxGLContext and wxGLCanvas
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxGLContext
  11
  12     An instance of a wxGLContext represents the state of an OpenGL state
  13     machine and the connection between OpenGL and the system.
  14
  15     The OpenGL state includes everything that can be set with the OpenGL API:
  16     colors, rendering variables, display lists, texture objects, etc. Although
  17     it is possible to have multiple rendering contexts share display lists in
  18     order to save resources, this method is hardly used today any more, because
  19     display lists are only a tiny fraction of the overall state.
  20
  21     Therefore, one rendering context is usually used with or bound to multiple
  22     output windows in turn, so that the application has access to the complete
  23     and identical state while rendering into each window.
  24
  25     Binding (making current) a rendering context with another instance of a
  26     wxGLCanvas however works only if the other wxGLCanvas was created with the
  27     same attributes as the wxGLCanvas from which the wxGLContext was
  28     initialized. (This applies to sharing display lists among contexts
  29     analogously.)
  30
  31     Note that some wxGLContext features are extremely platform-specific - its
  32     best to check your native platform's glcanvas header (on windows
  33     include/wx/msw/glcanvas.h) to see what features your native platform
  34     provides.
  35
  36     @library{wxgl}
  37     @category{gl}
  38
  39     @see wxGLCanvas
  40 */
  41 class wxGLContext : public wxObject
  42 {
  43 public:
  44     /**
  45         Constructor.
  46
  47         @param win
  48             The canvas that is used to initialize this context. This parameter
  49             is needed only temporarily, and the caller may do anything with it
  50             (e.g. destroy the window) after the constructor returned. @n
  51             It will be possible to bind (make current) this context to any
  52             other wxGLCanvas that has been created with equivalent attributes
  53             as win.
  54         @param other
  55             Context to share display lists with or @NULL (the default) for no
  56             sharing.
  57     */
  58     wxGLContext(wxGLCanvas* win, const wxGLContext* other = NULL);
  59
  60     /**
  61         Makes the OpenGL state that is represented by this rendering context
  62         current with the wxGLCanvas @e win.
  63
  64         @note @a win can be a different wxGLCanvas window than the one that was
  65               passed to the constructor of this rendering context. If @e RC is
  66               an object of type wxGLContext, the statements
  67               @e "RC.SetCurrent(win);" and @e "win.SetCurrent(RC);" are
  68               equivalent, see wxGLCanvas::SetCurrent().
  69     */
  70     virtual bool SetCurrent(const wxGLCanvas& win) const;
  71 };
  72
  73 /**
  74     @anchor wxGL_FLAGS
  75
  76     Constants for use with wxGLCanvas.
  77
  78     @note Not all implementations support options such as stereo, auxiliary
  79           buffers, alpha channel, and accumulator buffer, use
  80           wxGLCanvas::IsDisplaySupported() to check for individual attributes
  81           support.
  82  */
  83 enum
  84 {
  85     /// Use true color (the default if no attributes at all are specified);
  86     /// do not use a palette.
  87     WX_GL_RGBA = 1,
  88
  89     /// Specifies the number of bits for buffer if not WX_GL_RGBA.
  90     WX_GL_BUFFER_SIZE,
  91
  92     /// Must be followed by 0 for main buffer, >0 for overlay, <0 for underlay.
  93     WX_GL_LEVEL,
  94
  95     /// Use double buffering if present (on if no attributes specified).
  96     WX_GL_DOUBLEBUFFER,
  97
  98     /// Use stereoscopic display.
  99     WX_GL_STEREO,
 100
 101     /// Specifies number of auxiliary buffers.
 102     WX_GL_AUX_BUFFERS,
 103
 104     /// Use red buffer with most bits (> MIN_RED bits)
 105     WX_GL_MIN_RED,
 106
 107     /// Use green buffer with most bits (> MIN_GREEN bits)
 108     WX_GL_MIN_GREEN,
 109
 110     /// Use blue buffer with most bits (> MIN_BLUE bits)
 111     WX_GL_MIN_BLUE,
 112
 113     /// Use alpha buffer with most bits (> MIN_ALPHA bits)
 114     WX_GL_MIN_ALPHA,
 115
 116     /// Specifies number of bits for Z-buffer (typically 0, 16 or 32).
 117     WX_GL_DEPTH_SIZE,
 118
 119     /// Specifies number of bits for stencil buffer.
 120     WX_GL_STENCIL_SIZE,
 121
 122     /// Specifies minimal number of red accumulator bits.
 123     WX_GL_MIN_ACCUM_RED,
 124
 125     /// Specifies minimal number of green accumulator bits.
 126     WX_GL_MIN_ACCUM_GREEN,
 127
 128     /// Specifies minimal number of blue accumulator bits.
 129     WX_GL_MIN_ACCUM_BLUE,
 130
 131     /// Specifies minimal number of alpha accumulator bits.
 132     WX_GL_MIN_ACCUM_ALPHA,
 133
 134     /// 1 for multisampling support (antialiasing)
 135     WX_GL_SAMPLE_BUFFERS,
 136
 137     /// 4 for 2x2 antialising supersampling on most graphics cards
 138     WX_GL_SAMPLES
 139
 140 };
 141
 142 /**
 143     @class wxGLCanvas
 144
 145     wxGLCanvas is a class for displaying OpenGL graphics. It is always used in
 146     conjunction with wxGLContext as the context can only be made current (i.e.
 147     active for the OpenGL commands) when it is associated to a wxGLCanvas.
 148
 149     More precisely, you first need to create a wxGLCanvas window and then
 150     create an instance of a wxGLContext that is initialized with this
 151     wxGLCanvas and then later use either SetCurrent() with the instance of the
 152     wxGLContext or wxGLContext::SetCurrent() with the instance of the
 153     wxGLCanvas (which might be not the same as was used for the creation of the
 154     context) to bind the OpenGL state that is represented by the rendering
 155     context to the canvas, and then finally call SwapBuffers() to swap the
 156     buffers of the OpenGL canvas and thus show your current output.
 157
 158     Notice that versions of wxWidgets previous to 2.9 used to implicitly create a
 159     wxGLContext inside wxGLCanvas itself. This is still supported in the
 160     current version but is deprecated now and will be removed in the future,
 161     please update your code to create the rendering contexts explicitly.
 162
 163     To set up the attributes for the canvas (number of bits for the depth
 164     buffer, number of bits for the stencil buffer and so on) you should set up
 165     the correct values of the @e attribList parameter. The values that should
 166     be set up and their meanings will be described below.
 167
 168     @note
 169         On those platforms which use a configure script (e.g. Linux and Mac OS)
 170         OpenGL support is automatically enabled if the relative headers and
 171         libraries are found.
 172         To switch it on under the other platforms (e.g. Windows), you need to edit
 173         the @c setup.h file and set @c wxUSE_GLCANVAS to @c 1 and then also pass
 174         @c USE_OPENGL=1 to the make utility. You may also need to add @c opengl32.lib
 175         and @c glu32.lib to the list of the libraries your program is linked with.
 176
 177     @library{wxgl}
 178     @category{gl}
 179
 180     @see wxGLContext
 181 */
 182 class wxGLCanvas : public wxWindow
 183 {
 184 public:
 185     /**
 186         Creates a window with the given parameters. Notice that you need to
 187         create and use a wxGLContext to output to this window.
 188
 189         If @a attribList is not specified, double buffered RGBA mode is used.
 190
 191         @param parent
 192             Pointer to a parent window.
 193         @param id
 194             Window identifier. If -1, will automatically create an identifier.
 195         @param pos
 196             Window position. wxDefaultPosition is (-1, -1) which indicates that
 197             wxWidgets should generate a default position for the window.
 198         @param size
 199             Window size. wxDefaultSize is (-1, -1) which indicates that
 200             wxWidgets should generate a default size for the window. If no
 201             suitable size can be found, the window will be sized to 20x20
 202             pixels so that the window is visible but obviously not correctly
 203             sized.
 204         @param style
 205             Window style.
 206         @param name
 207             Window name.
 208         @param attribList
 209             Array of integers. With this parameter you can set the device
 210             context attributes associated to this window. This array is
 211             zero-terminated: it should be set up using @ref wxGL_FLAGS
 212             constants. If a constant should be followed by a value, put it in
 213             the next array position. For example, WX_GL_DEPTH_SIZE should be
 214             followed by the value that indicates the number of bits for the
 215             depth buffer, e.g:
 216             @code
 217             attribList[n++] = WX_GL_DEPTH_SIZE;
 218             attribList[n++] = 32;
 219             attribList[n] = 0; // terminate the list
 220             @endcode
 221             If the attribute list is not specified at all, i.e. if this
 222             parameter is @NULL, the default attributes including WX_GL_RGBA and
 223             WX_GL_DOUBLEBUFFER are used. But notice that if you do specify some
 224             attributes you also need to explicitly include these two default
 225             attributes in the list if you need them.
 226         @param palette
 227             Palette for indexed colour (i.e. non WX_GL_RGBA) mode. Ignored
 228             under most platforms.
 229     */
 230     wxGLCanvas(wxWindow* parent, wxWindowID id = wxID_ANY,
 231                const int* attribList = NULL,
 232                const wxPoint& pos = wxDefaultPosition,
 233                const wxSize& size = wxDefaultSize,
 234                long style = 0,
 235                const wxString& name = "GLCanvas",
 236                const wxPalette& palette = wxNullPalette);
 237
 238     /**
 239         Determines if a canvas having the specified attributes is available.
 240
 241         @param attribList
 242             See @a attribList for wxGLCanvas().
 243
 244         @return @true if attributes are supported.
 245     */
 246     static bool IsDisplaySupported(const int* attribList = NULL);
 247
 248     /**
 249         Returns true if the extension with given name is supported
 250
 251         Notice that while this function is implemented for all of GLX, WGL and
 252         AGL the extensions names are usually not the same for different
 253         platforms and so the code using it still usually uses conditional
 254         compilation.
 255     */
 256     static bool IsExtensionSupported(const char *extension);
 257
 258     /**
 259         Sets the current colour for this window (using @c glcolor3f()), using
 260         the wxWidgets colour database to find a named colour.
 261     */
 262     bool SetColour(const wxString& colour);
 263
 264     /**
 265         Makes the OpenGL state that is represented by the OpenGL rendering
 266         context @a context current, i.e. it will be used by all subsequent
 267         OpenGL calls.
 268
 269         This is equivalent to wxGLContext::SetCurrent() called with this window
 270         as parameter.
 271
 272         @note This function may only be called when the window is shown on
 273               screen, in particular it can't usually be called from the
 274               constructor as the window isn't yet shown at this moment.
 275
 276         @return @false if an error occurred.
 277     */
 278     bool SetCurrent(const wxGLContext& context) const;
 279
 280     /**
 281         Swaps the double-buffer of this window, making the back-buffer the
 282         front-buffer and vice versa, so that the output of the previous OpenGL
 283         commands is displayed on the window.
 284
 285         @return @false if an error occurred.
 286     */
 287     virtual bool SwapBuffers();
 288 };