Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.opengl; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.internal.*; import org.eclipse.swt.internal.gtk.*; import org.eclipse.swt.internal.opengl.glx.*; import org.eclipse.swt.widgets.*; /** * GLCanvas is a widget capable of displaying OpenGL content. * * @see GLData * @see <a href="http://www.eclipse.org/swt/snippets/#opengl">OpenGL snippets</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * * @since 3.2 */ public class GLCanvas extends Canvas { long context; long xWindow; long glWindow; XVisualInfo vinfo; static final int MAX_ATTRIBUTES = 32; /** * Create a GLCanvas widget using the attributes described in the GLData * object provided. * * @param parent a composite widget * @param style the bitwise OR'ing of widget styles * @param data the requested attributes of the GLCanvas * * @exception IllegalArgumentException * <ul><li>ERROR_NULL_ARGUMENT when the data is null</li> * <li>ERROR_UNSUPPORTED_DEPTH when the requested attributes cannot be provided</li> * </ul> */ public GLCanvas(Composite parent, int style, GLData data) { super(parent, style); if (OS.IsWin32) SWT.error(SWT.ERROR_NOT_IMPLEMENTED); if (data == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); int glxAttrib[] = new int[MAX_ATTRIBUTES]; int pos = 0; glxAttrib[pos++] = GLX.GLX_RGBA; if (data.doubleBuffer) glxAttrib[pos++] = GLX.GLX_DOUBLEBUFFER; if (data.stereo) glxAttrib[pos++] = GLX.GLX_STEREO; if (data.redSize > 0) { glxAttrib[pos++] = GLX.GLX_RED_SIZE; glxAttrib[pos++] = data.redSize; } if (data.greenSize > 0) { glxAttrib[pos++] = GLX.GLX_GREEN_SIZE; glxAttrib[pos++] = data.greenSize; } if (data.blueSize > 0) { glxAttrib[pos++] = GLX.GLX_BLUE_SIZE; glxAttrib[pos++] = data.blueSize; } if (data.alphaSize > 0) { glxAttrib[pos++] = GLX.GLX_ALPHA_SIZE; glxAttrib[pos++] = data.alphaSize; } if (data.depthSize > 0) { glxAttrib[pos++] = GLX.GLX_DEPTH_SIZE; glxAttrib[pos++] = data.depthSize; } if (data.stencilSize > 0) { glxAttrib[pos++] = GLX.GLX_STENCIL_SIZE; glxAttrib[pos++] = data.stencilSize; } if (data.accumRedSize > 0) { glxAttrib[pos++] = GLX.GLX_ACCUM_RED_SIZE; glxAttrib[pos++] = data.accumRedSize; } if (data.accumGreenSize > 0) { glxAttrib[pos++] = GLX.GLX_ACCUM_GREEN_SIZE; glxAttrib[pos++] = data.accumGreenSize; } if (data.accumBlueSize > 0) { glxAttrib[pos++] = GLX.GLX_ACCUM_BLUE_SIZE; glxAttrib[pos++] = data.accumBlueSize; } if (data.accumAlphaSize > 0) { glxAttrib[pos++] = GLX.GLX_ACCUM_ALPHA_SIZE; glxAttrib[pos++] = data.accumAlphaSize; } if (data.sampleBuffers > 0) { glxAttrib[pos++] = GLX.GLX_SAMPLE_BUFFERS; glxAttrib[pos++] = data.sampleBuffers; } if (data.samples > 0) { glxAttrib[pos++] = GLX.GLX_SAMPLES; glxAttrib[pos++] = data.samples; } glxAttrib[pos++] = 0; GTK.gtk_widget_realize(handle); long window = GTK.gtk_widget_get_window(handle); long xDisplay = GDK.gdk_x11_display_get_xdisplay(GDK.gdk_window_get_display(window)); long infoPtr = GLX.glXChooseVisual(xDisplay, OS.XDefaultScreen(xDisplay), glxAttrib); if (infoPtr == 0) { dispose(); SWT.error(SWT.ERROR_UNSUPPORTED_DEPTH); } vinfo = new XVisualInfo(); GLX.memmove(vinfo, infoPtr, XVisualInfo.sizeof); OS.XFree(infoPtr); long screen = GDK.gdk_screen_get_default(); long gdkvisual = GDK.gdk_x11_screen_lookup_visual(screen, vinfo.visualid); long share = data.shareContext != null ? data.shareContext.context : 0; context = GLX.glXCreateContext(xDisplay, vinfo, share, true); if (context == 0) SWT.error(SWT.ERROR_NO_HANDLES); GdkWindowAttr attrs = new GdkWindowAttr(); attrs.width = 1; attrs.height = 1; attrs.event_mask = GDK.GDK_KEY_PRESS_MASK | GDK.GDK_KEY_RELEASE_MASK | GDK.GDK_FOCUS_CHANGE_MASK | GDK.GDK_POINTER_MOTION_MASK | GDK.GDK_BUTTON_PRESS_MASK | GDK.GDK_BUTTON_RELEASE_MASK | GDK.GDK_ENTER_NOTIFY_MASK | GDK.GDK_LEAVE_NOTIFY_MASK | GDK.GDK_EXPOSURE_MASK | GDK.GDK_POINTER_MOTION_HINT_MASK; attrs.window_type = GDK.GDK_WINDOW_CHILD; attrs.visual = gdkvisual; glWindow = GDK.gdk_window_new(window, attrs, GDK.GDK_WA_VISUAL); GDK.gdk_window_set_user_data(glWindow, handle); if ((style & SWT.NO_BACKGROUND) != 0) { //TODO: implement this on GTK3 as pixmaps are gone. } xWindow = GDK.gdk_x11_window_get_xid(glWindow); GDK.gdk_window_show(glWindow); Listener listener = event -> { switch (event.type) { case SWT.Paint: /** * Bug in MESA. MESA does some nasty sort of polling to try * and ensure that their buffer sizes match the current X state. * This state can be updated using glViewport(). * FIXME: There has to be a better way of doing this. */ int[] viewport = new int[4]; GLX.glGetIntegerv(GLX.GL_VIEWPORT, viewport); GLX.glViewport(viewport[0], viewport[1], viewport[2], viewport[3]); break; case SWT.Resize: Rectangle clientArea = DPIUtil.autoScaleUp(getClientArea()); GDK.gdk_window_move(glWindow, clientArea.x, clientArea.y); GDK.gdk_window_resize(glWindow, clientArea.width, clientArea.height); break; case SWT.Dispose: long window1 = GTK.gtk_widget_get_window(handle); long xDisplay1 = gdk_x11_display_get_xdisplay(window1); if (context != 0) { if (GLX.glXGetCurrentContext() == context) { GLX.glXMakeCurrent(xDisplay1, 0, 0); } GLX.glXDestroyContext(xDisplay1, context); context = 0; } if (glWindow != 0) { GDK.gdk_window_destroy(glWindow); glWindow = 0; } break; } }; addListener(SWT.Resize, listener); addListener(SWT.Paint, listener); addListener(SWT.Dispose, listener); } /** * Returns a GLData object describing the created context. * * @return GLData description of the OpenGL context attributes * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public GLData getGLData() { checkWidget(); long window = GTK.gtk_widget_get_window(handle); long xDisplay = gdk_x11_display_get_xdisplay(window); GLData data = new GLData(); int[] value = new int[1]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_DOUBLEBUFFER, value); data.doubleBuffer = value[0] != 0; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_STEREO, value); data.stereo = value[0] != 0; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_RED_SIZE, value); data.redSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_GREEN_SIZE, value); data.greenSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_BLUE_SIZE, value); data.blueSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_ALPHA_SIZE, value); data.alphaSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_DEPTH_SIZE, value); data.depthSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_STENCIL_SIZE, value); data.stencilSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_ACCUM_RED_SIZE, value); data.accumRedSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_ACCUM_GREEN_SIZE, value); data.accumGreenSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_ACCUM_BLUE_SIZE, value); data.accumBlueSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_ACCUM_ALPHA_SIZE, value); data.accumAlphaSize = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_SAMPLE_BUFFERS, value); data.sampleBuffers = value[0]; GLX.glXGetConfig(xDisplay, vinfo, GLX.GLX_SAMPLES, value); data.samples = value[0]; return data; } /** * Returns a boolean indicating whether the receiver's OpenGL context * is the current context. * * @return true if the receiver holds the current OpenGL context, * false otherwise * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public boolean isCurrent() { checkWidget(); return GLX.glXGetCurrentContext() == context; } /** * Sets the OpenGL context associated with this GLCanvas to be the * current GL context. * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setCurrent() { checkWidget(); if (GLX.glXGetCurrentContext() == context) return; long window = GTK.gtk_widget_get_window(handle); long xDisplay = gdk_x11_display_get_xdisplay(window); GLX.glXMakeCurrent(xDisplay, xWindow, context); } /** * Swaps the front and back color buffers. * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void swapBuffers() { checkWidget(); long window = GTK.gtk_widget_get_window(handle); long xDisplay = gdk_x11_display_get_xdisplay(window); GLX.glXSwapBuffers(xDisplay, xWindow); } private long gdk_x11_display_get_xdisplay(long window) { return GDK.gdk_x11_display_get_xdisplay(GDK.gdk_window_get_display(window)); } }