GLCanvas


1   /*******************************************************************************
2    * Copyright (c) 2000, 2007 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.swt.opengl;
12  
13  import org.eclipse.swt.*;
14  import org.eclipse.swt.widgets.*;
15  import org.eclipse.swt.internal.win32.*;
16  import org.eclipse.swt.internal.opengl.win32.*;
17  
18  /**
19   * GLCanvas is a widget capable of displaying OpenGL content.
20   * 
21   * @since 3.2
22   */
23  
24  public class GLCanvas extends Canvas {
25      int context;
26      int pixelFormat;
27  
28  /**
29   * Create a GLCanvas widget using the attributes described in the GLData
30   * object provided.
31   *
32   * @param parent a composite widget
33   * @param style the bitwise OR'ing of widget styles
34   * @param data the requested attributes of the GLCanvas
35   *
36   * @exception IllegalArgumentException
37   * <ul><li>ERROR_NULL_ARGUMENT when the data is null
38   *     <li>ERROR_UNSUPPORTED_DEPTH when the requested attributes cannot be provided</ul> 
39   * </ul>
40   */
41  public GLCanvas (Composite parent, int style, GLData data) {
42      super (parent, style);
43      if (data == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
44      PIXELFORMATDESCRIPTOR pfd = new PIXELFORMATDESCRIPTOR ();
45      pfd.nSize = (short) PIXELFORMATDESCRIPTOR.sizeof;
46      pfd.nVersion = 1;
47      pfd.dwFlags = WGL.PFD_DRAW_TO_WINDOW | WGL.PFD_SUPPORT_OPENGL;
48      pfd.dwLayerMask = WGL.PFD_MAIN_PLANE;
49      pfd.iPixelType = (byte) WGL.PFD_TYPE_RGBA;
50      if (data.doubleBuffer) pfd.dwFlags |= WGL.PFD_DOUBLEBUFFER;
51      if (data.stereo) pfd.dwFlags |= WGL.PFD_STEREO;
52      pfd.cRedBits = (byte) data.redSize;
53      pfd.cGreenBits = (byte) data.greenSize;
54      pfd.cBlueBits = (byte) data.blueSize;
55      pfd.cAlphaBits = (byte) data.alphaSize;
56      pfd.cDepthBits = (byte) data.depthSize;
57      pfd.cStencilBits = (byte) data.stencilSize;
58      pfd.cAccumRedBits = (byte) data.accumRedSize;
59      pfd.cAccumGreenBits = (byte) data.accumGreenSize;
60      pfd.cAccumBlueBits = (byte) data.accumBlueSize;
61      pfd.cAccumAlphaBits = (byte) data.accumAlphaSize;
62      pfd.cAccumBits = (byte) (pfd.cAccumRedBits + pfd.cAccumGreenBits + pfd.cAccumBlueBits + pfd.cAccumAlphaBits);
63      
64      //FIXME - use wglChoosePixelFormatARB
65  //  if (data.sampleBuffers > 0) {
66  //      wglAttrib [pos++] = WGL.WGL_SAMPLE_BUFFERS_ARB;
67  //      wglAttrib [pos++] = data.sampleBuffers;
68  //  }
69  //  if (data.samples > 0) {
70  //      wglAttrib [pos++] = WGL.WGL_SAMPLES_ARB;
71  //      wglAttrib [pos++] = data.samples;
72  //  }
73  
74      int hDC = OS.GetDC (handle);
75      pixelFormat = WGL.ChoosePixelFormat (hDC, pfd);
76      if (pixelFormat == 0 || !WGL.SetPixelFormat (hDC, pixelFormat, pfd)) {
77          OS.ReleaseDC (handle, hDC);
78          dispose ();
79          SWT.error (SWT.ERROR_UNSUPPORTED_DEPTH);
80      }
81      context = WGL.wglCreateContext (hDC);
82      if (context == 0) {
83          OS.ReleaseDC (handle, hDC);
84          SWT.error (SWT.ERROR_NO_HANDLES);
85      }
86      OS.ReleaseDC (handle, hDC);
87      //FIXME- share lists
88      //if (share != null) WGL.wglShareLists (context, share.context);
89      
90      Listener listener = new Listener () {
91          public void handleEvent (Event event) {
92              switch (event.type) {
93                  case SWT.Dispose:
94                      WGL.wglDeleteContext (context);
95                      break;
96              }
97          }
98      };
99      addListener (SWT.Dispose, listener);
100 }
101 
102 /**
103  * Returns a GLData object describing the created context.
104  *  
105  * @return GLData description of the OpenGL context attributes
106  * @exception SWTException <ul>
107  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
108  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
109  * </ul>
110  */
111 public GLData getGLData () {
112     checkWidget ();
113     GLData data = new GLData ();
114     PIXELFORMATDESCRIPTOR pfd = new PIXELFORMATDESCRIPTOR ();
115     pfd.nSize = (short) PIXELFORMATDESCRIPTOR.sizeof;
116     int hDC = OS.GetDC (handle);
117     WGL.DescribePixelFormat (hDC, pixelFormat, PIXELFORMATDESCRIPTOR.sizeof, pfd);
118     OS.ReleaseDC (handle, hDC);
119     data.doubleBuffer = (pfd.dwFlags & WGL.PFD_DOUBLEBUFFER) != 0;
120     data.stereo = (pfd.dwFlags & WGL.PFD_STEREO) != 0;
121     data.redSize = pfd.cRedBits;
122     data.greenSize = pfd.cGreenBits;
123     data.blueSize = pfd.cBlueBits;
124     data.alphaSize = pfd.cAlphaBits;
125     data.depthSize = pfd.cDepthBits;
126     data.stencilSize = pfd.cStencilBits;
127     data.accumRedSize = pfd.cAccumRedBits;
128     data.accumGreenSize = pfd.cAccumGreenBits;
129     data.accumBlueSize = pfd.cAccumBlueBits;
130     data.accumAlphaSize = pfd.cAccumAlphaBits;
131     return data;
132 }
133 
134 /**
135  * Returns a boolean indicating whether the receiver's OpenGL context
136  * is the current context.
137  *  
138  * @return true if the receiver holds the current OpenGL context,
139  * false otherwise
140  * @exception SWTException <ul>
141  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
142  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
143  * </ul>
144  */
145 public boolean isCurrent () {
146     checkWidget ();
147     return WGL.wglGetCurrentContext () == context;
148 }
149 
150 /**
151  * Sets the OpenGL context associated with this GLCanvas to be the
152  * current GL context.
153  * 
154  * @exception SWTException <ul>
155  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
156  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
157  * </ul>
158  */
159 public void setCurrent () {
160     checkWidget ();
161     if (WGL.wglGetCurrentContext () == context) return;
162     int hDC = OS.GetDC (handle);
163     WGL.wglMakeCurrent (hDC, context);
164     OS.ReleaseDC (handle, hDC);
165 }
166 
167 /**
168  * Swaps the front and back color buffers.
169  * 
170  * @exception SWTException <ul>
171  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
172  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
173  * </ul>
174  */
175 public void swapBuffers () {
176     checkWidget ();
177     int hDC = OS.GetDC (handle);
178     WGL.SwapBuffers (hDC);
179     OS.ReleaseDC (handle, hDC);
180 }
181 }
182
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