multi window with opengl
Author
I have created two windows, but my (simple... i hope) problem is to draw into them. Do we have some function to tell OpenGL to render INTO a particular window? (switch between more wnds) possible send HWND or HDC? how?
please help, i have no idea...
As far as I know OpenGL will always render into the window which is in the same thread. Don''t know of any parameters to pass... Never tried what happens if you have two windows in the same thread, but you could just create two threads, give each it''s own window and gl-commands?
Author
no, I think that OpenGL library (=dll) is loaded only once for INSTANCE, threads are only using imported funcs.
idea (maybe helpful) what exactly does wglMakeCurrent() and wglCreateContext() and that third wgl_something_()? I never thought about them.
idea (maybe helpful) what exactly does wglMakeCurrent() and wglCreateContext() and that third wgl_something_()? I never thought about them.
quote:from MSDN The wglMakeCurrent function makes a specified OpenGL rendering context the calling thread''s current rendering context. All subsequent OpenGL calls made by the thread are drawn on the device identified by hdc. You can also use wglMakeCurrent to change the calling thread''s current rendering context so it''s no longer current.
So, if you have two threads, each OpenGL call inside the thread will be made to the opengl rendering context of that thread. The other stuff is for creating a rendering context and binding it to a window.
This should help, it renders 4 opengl screens each in an edit control in a dialogbox. Plus this is in Win32 API 
What you can basically do with this is create windows within your window, get their DCs and Wiggles then render.
Main Source File
Resource ID file
Resource File
Hope that helps.
[edit] Misspelled a tag.
[edited by - Xiachunyi on August 11, 2003 11:59:02 AM]
What you can basically do with this is create windows within your window, get their DCs and Wiggles then render.
Main Source File
// windowopengl.cpp : Defines the entry point for the application.//#include "stdafx.h"#include "resource.h"#include <gl\glut.h>#include <gl\gl.h>#include <gl\glaux.h>#define MAX_LOADSTRING 100// Global Variables:HINSTANCE hInst; // current instanceTCHAR szTitle[MAX_LOADSTRING]; // The title bar textTCHAR szWindowClass[MAX_LOADSTRING]; // The title bar textint TheEnd; // Flag used by thread to end int xrot; // rotation// Foward declarations of functions included in this code module:ATOM MyRegisterClass(HINSTANCE hInstance);BOOL InitInstance(HINSTANCE, int);LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);LRESULT CALLBACK OpenGL(HWND, UINT, WPARAM, LPARAM);DWORD WINAPI InitGL(HWND);int MySetPixelFormat(HDC hdc);void RenderScene(int);int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow){ // TODO: Place code here. MSG msg; HACCEL hAccelTable; // Initialize global strings LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING); LoadString(hInstance, IDC_WINDOWOPENGL, szWindowClass, MAX_LOADSTRING); MyRegisterClass(hInstance); // Perform application initialization: if (!InitInstance (hInstance, nCmdShow)) { return FALSE; } hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_WINDOWOPENGL); // Main message loop: while (GetMessage(&msg, NULL, 0, 0)) { if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) { TranslateMessage(&msg); DispatchMessage(&msg); } } return msg.wParam;}//// FUNCTION: MyRegisterClass()//// PURPOSE: Registers the window class.//// COMMENTS://// This function and its usage is only necessary if you want this code// to be compatible with Win32 systems prior to the 'RegisterClassEx'// function that was added to Windows 95. It is important to call this function// so that the application will get 'well formed' small icons associated// with it.//ATOM MyRegisterClass(HINSTANCE hInstance){ WNDCLASSEX wcex; wcex.cbSize = sizeof(WNDCLASSEX); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = (WNDPROC)WndProc; wcex.cbClsExtra = 0; wcex.cbWndExtra = 0; wcex.hInstance = hInstance; wcex.hIcon = LoadIcon(hInstance, (LPCTSTR)IDI_WINDOWOPENGL); wcex.hCursor = LoadCursor(NULL, IDC_ARROW); wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1); wcex.lpszMenuName = (LPCSTR)IDC_WINDOWOPENGL; wcex.lpszClassName = szWindowClass; wcex.hIconSm = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL); return RegisterClassEx(&wcex);}//// FUNCTION: InitInstance(HANDLE, int)//// PURPOSE: Saves instance handle and creates main window//// COMMENTS://// In this function, we save the instance handle in a global variable and// create and display the main program window.//BOOL InitInstance(HINSTANCE hInstance, int nCmdShow){ HWND hWnd; hInst = hInstance; // Store instance handle in our global variable hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL); if (!hWnd) { return FALSE; } ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); return TRUE;}//// FUNCTION: WndProc(HWND, unsigned, WORD, LONG)//// PURPOSE: Processes messages for the main window.//// WM_COMMAND - process the application menu// WM_PAINT - Paint the main window// WM_DESTROY - post a quit message and return////LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ int wmId, wmEvent; PAINTSTRUCT ps; HDC hdc; TCHAR szHello[MAX_LOADSTRING]; LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING); switch (message) { case WM_COMMAND: wmId = LOWORD(wParam); wmEvent = HIWORD(wParam); // Parse the menu selections: switch (wmId) { case IDM_ABOUT: DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About); break; case IDM_EXIT: DestroyWindow(hWnd); break; case IDM_OPENGL: DialogBox(hInst, (LPCTSTR)IDD_OPENGL, hWnd, (DLGPROC)OpenGL); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } break; case WM_PAINT: hdc = BeginPaint(hWnd, &ps); // TODO: Add any drawing code here... RECT rt; GetClientRect(hWnd, &rt); DrawText(hdc, szHello, strlen(szHello), &rt, DT_CENTER); EndPaint(hWnd, &ps); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } return 0;}// Mesage handler for about box.LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam){ switch (message) { case WM_INITDIALOG: return TRUE; case WM_COMMAND: if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) { EndDialog(hDlg, LOWORD(wParam)); return TRUE; } break; } return FALSE;}// Mesage handler for OpenGL box.LRESULT CALLBACK OpenGL(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam){ static HANDLE hOpenGL; static DWORD lpThreadId; switch (message) { case WM_INITDIALOG: return TRUE; case WM_COMMAND: if (LOWORD(wParam) == IDOK) { TheEnd=1; Sleep(500); EndDialog(hDlg, LOWORD(wParam)); return TRUE; } if (LOWORD(wParam) == IDRENDER) { EnableWindow(GetDlgItem(hDlg,IDRENDER),FALSE); hOpenGL=CreateThread(NULL,NULL,(LPTHREAD_START_ROUTINE)InitGL,hDlg,0,&lpThreadId); } break; } return FALSE;}// Here, we do the regular initialization of OpenGLDWORD WINAPI InitGL(HWND hDlg){ HDC hDC1,hDC2,hDC3,hDC4; HWND hEdit1,hEdit2,hEdit3,hEdit4; HGLRC hglrc1,hglrc2,hglrc3,hglrc4; // First, let's get the handle to all the window we created in the Dialog // with the resource editor hEdit1=GetDlgItem(hDlg,IDC_EDIT1); hEdit2=GetDlgItem(hDlg,IDC_EDIT2); hEdit3=GetDlgItem(hDlg,IDC_EDIT3); hEdit4=GetDlgItem(hDlg,IDC_EDIT4); // For every window, we get the HDC hDC1=GetDC(hEdit1); hDC2=GetDC(hEdit2); hDC3=GetDC(hEdit3); hDC4=GetDC(hEdit4); // OpenGL Initialization glShadeModel(GL_SMOOTH); // Enable Smooth Shading glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background glClearDepth(1.0f); // Depth Buffer Setup glEnable(GL_DEPTH_TEST); // Enables Depth Testing glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations MySetPixelFormat(hDC1); MySetPixelFormat(hDC2); MySetPixelFormat(hDC3); MySetPixelFormat(hDC4); hglrc1 = wglCreateContext(hDC1); hglrc2 = wglCreateContext(hDC2); hglrc3 = wglCreateContext(hDC3); hglrc4 = wglCreateContext(hDC4); //render here while(TheEnd !=1 ) { // Select first Window as the rendering context and draw to it wglMakeCurrent(hDC1, hglrc1); RenderScene(1); SwapBuffers(hDC1); // Select second Window as the rendering context and draw to it wglMakeCurrent(hDC2, hglrc2); RenderScene(2); SwapBuffers(hDC2); // Select third Window as the rendering context and draw to it wglMakeCurrent(hDC3, hglrc3); RenderScene(2); SwapBuffers(hDC3); // Select fourth Window as the rendering context and draw to it wglMakeCurrent(hDC4, hglrc4); RenderScene(1); SwapBuffers(hDC4); // Throttle the loop. If we don't put a sleep here, the thread will use 100% cpu Sleep(1); } wglMakeCurrent(NULL, NULL); // Cleanup ReleaseDC (hDlg, hDC1) ; ReleaseDC (hDlg, hDC2) ; ReleaseDC (hDlg, hDC3) ; ReleaseDC (hDlg, hDC4) ; wglDeleteContext(hglrc1); wglDeleteContext(hglrc2); wglDeleteContext(hglrc3); wglDeleteContext(hglrc4); return TRUE;}// Set up the pixel formatint MySetPixelFormat(HDC hdc){ PIXELFORMATDESCRIPTOR pfd = { sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd 1, // version number PFD_DRAW_TO_WINDOW | // support window PFD_SUPPORT_OPENGL | // support OpenGL PFD_DOUBLEBUFFER, // double buffered PFD_TYPE_RGBA, // RGBA type 24, // 24-bit color depth 0, 0, 0, 0, 0, 0, // color bits ignored 0, // no alpha buffer 0, // shift bit ignored 0, // no accumulation buffer 0, 0, 0, 0, // accum bits ignored 32, // 32-bit z-buffer 0, // no stencil buffer 0, // no auxiliary buffer PFD_MAIN_PLANE, // main layer 0, // reserved 0, 0, 0 // layer masks ignored }; int iPixelFormat; // get the device context's best, available pixel format match if((iPixelFormat = ChoosePixelFormat(hdc, &pfd)) == 0) { MessageBox(NULL, "ChoosePixelFormat Failed", NULL, MB_OK); return 0; } // make that match the device context's current pixel format if(SetPixelFormat(hdc, iPixelFormat, &pfd) == FALSE) { MessageBox(NULL, "SetPixelFormat Failed", NULL, MB_OK); return 0; } return 1;}// This is where we render, in this case, we will draw a simple 3D-Trianglevoid RenderScene(int axis){ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); if(axis==1) glRotatef(xrot,1.0f,0.0f,0.0f); if(axis==2) glRotatef(xrot,0.0f,1.0f,0.0f); glBegin(GL_TRIANGLES); glColor3f(1, 0, 0); glVertex3f(0, 0.8f, 0); //top glColor3f(0, 1, 0); glVertex3f(-0.5, -0.5, 0.5); //left glColor3f(0, 0,1); glVertex3f(0.5, -0.5, 0.5); //right glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Right) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f( .5f,-.5f, .5f); // Left Of Triangle (Right) glColor3f(0.0f,0.5f,0.0f); // Green glVertex3f( 0.5f,-0.5f, -0.5f); // Right Of Triangle (Right) glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Back) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f( 0.5f,-0.5f, -0.5f); // Left Of Triangle (Back) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f(-0.5f,-0.5f, -0.5f); // Right Of Triangle (Back) glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Left) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f(-0.5f,-0.5f,-0.5f); // Left Of Triangle (Left) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f(-0.5f,-0.5f, 0.5f); // Right Of Triangle (Left) glEnd(); xrot+=1.5f;}Resource ID file
//{{NO_DEPENDENCIES}}// Microsoft Developer Studio generated include file.// Used by windowopengl.rc//#define IDC_MYICON 2#define IDD_WINDOWOPENGL_DIALOG 102#define IDD_ABOUTBOX 103#define IDS_APP_TITLE 103#define IDM_ABOUT 104#define IDM_EXIT 105#define IDS_HELLO 106#define IDI_WINDOWOPENGL 107#define IDI_SMALL 108#define IDC_WINDOWOPENGL 109#define IDR_MAINFRAME 128#define IDD_OPENGL 129#define IDC_EDIT1 1000#define IDRENDER 1001#define IDC_EDIT2 1002#define IDC_EDIT3 1003#define IDC_EDIT4 1004#define IDM_OPENGL 32771#define IDC_STATIC -1// Next default values for new objects// #ifdef APSTUDIO_INVOKED#ifndef APSTUDIO_READONLY_SYMBOLS#define _APS_NEXT_RESOURCE_VALUE 130#define _APS_NEXT_COMMAND_VALUE 32772#define _APS_NEXT_CONTROL_VALUE 1002#define _APS_NEXT_SYMED_VALUE 110#endif#endifResource File
//Microsoft Developer Studio generated resource script.//#include "resource.h"#define APSTUDIO_READONLY_SYMBOLS///////////////////////////////////////////////////////////////////////////////// Generated from the TEXTINCLUDE 2 resource.//#define APSTUDIO_HIDDEN_SYMBOLS#include "windows.h"#undef APSTUDIO_HIDDEN_SYMBOLS#include "resource.h"/////////////////////////////////////////////////////////////////////////////#undef APSTUDIO_READONLY_SYMBOLS/////////////////////////////////////////////////////////////////////////////// English (U.S.) resources#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)#ifdef _WIN32LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US#pragma code_page(1252)#endif //_WIN32///////////////////////////////////////////////////////////////////////////////// Icon//// Icon with lowest ID value placed first to ensure application icon// remains consistent on all systems.IDI_WINDOWOPENGL ICON DISCARDABLE "windowopengl.ICO"IDI_SMALL ICON DISCARDABLE "SMALL.ICO"///////////////////////////////////////////////////////////////////////////////// Menu//IDC_WINDOWOPENGL MENU DISCARDABLE BEGIN POPUP "&File" BEGIN MENUITEM "E&xit", IDM_EXIT END MENUITEM "&OpenGL", IDM_OPENGL POPUP "&Help" BEGIN MENUITEM "&About ...", IDM_ABOUT ENDEND///////////////////////////////////////////////////////////////////////////////// Accelerator//IDC_WINDOWOPENGL ACCELERATORS MOVEABLE PURE BEGIN "?", IDM_ABOUT, ASCII, ALT "/", IDM_ABOUT, ASCII, ALTEND///////////////////////////////////////////////////////////////////////////////// Dialog//IDD_ABOUTBOX DIALOG DISCARDABLE 22, 17, 230, 75STYLE DS_MODALFRAME | WS_CAPTION | WS_SYSMENUCAPTION "About"FONT 8, "System"BEGIN ICON IDI_WINDOWOPENGL,IDC_MYICON,14,9,16,16 LTEXT "windowopengl Version 1.0",IDC_STATIC,49,10,119,8, SS_NOPREFIX LTEXT "Copyright (C) 2001",IDC_STATIC,49,20,119,8 DEFPUSHBUTTON "OK",IDOK,195,6,30,11,WS_GROUPENDIDD_OPENGL DIALOG DISCARDABLE 0, 0, 304, 170STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENUCAPTION "Window OpenGL example by Chong Hin Ooi, chongooi@mediaone.net"FONT 8, "MS Sans Serif"BEGIN DEFPUSHBUTTON "Render",IDRENDER,190,149,50,14 PUSHBUTTON "OK",IDOK,247,149,50,14 EDITTEXT IDC_EDIT1,7,7,138,58,ES_AUTOHSCROLL EDITTEXT IDC_EDIT2,159,7,138,58,ES_AUTOHSCROLL EDITTEXT IDC_EDIT3,7,78,138,58,ES_AUTOHSCROLL EDITTEXT IDC_EDIT4,159,78,138,58,ES_AUTOHSCROLLEND#ifdef APSTUDIO_INVOKED///////////////////////////////////////////////////////////////////////////////// TEXTINCLUDE//2 TEXTINCLUDE DISCARDABLE BEGIN "#define APSTUDIO_HIDDEN_SYMBOLS\r\n" "#include ""windows.h""\r\n" "#undef APSTUDIO_HIDDEN_SYMBOLS\r\n" "#include ""resource.h""\r\n" "\0"END3 TEXTINCLUDE DISCARDABLE BEGIN "\r\n" "\0"END1 TEXTINCLUDE DISCARDABLE BEGIN "resource.h\0"END#endif // APSTUDIO_INVOKED///////////////////////////////////////////////////////////////////////////////// DESIGNINFO//#ifdef APSTUDIO_INVOKEDGUIDELINES DESIGNINFO DISCARDABLE BEGIN IDD_OPENGL, DIALOG BEGIN LEFTMARGIN, 7 RIGHTMARGIN, 297 TOPMARGIN, 7 BOTTOMMARGIN, 163 ENDEND#endif // APSTUDIO_INVOKED///////////////////////////////////////////////////////////////////////////////// String Table//STRINGTABLE DISCARDABLE BEGIN IDS_APP_TITLE "windowopengl" IDS_HELLO "Window OpenGL example by Chong Hin Ooi" IDC_WINDOWOPENGL "WINDOWOPENGL"END#endif // English (U.S.) resources/////////////////////////////////////////////////////////////////////////////#ifndef APSTUDIO_INVOKED///////////////////////////////////////////////////////////////////////////////// Generated from the TEXTINCLUDE 3 resource.///////////////////////////////////////////////////////////////////////////////#endif // not APSTUDIO_INVOKEDHope that helps.
[edit] Misspelled a tag.
[edited by - Xiachunyi on August 11, 2003 11:59:02 AM]
Like the above poster''s example shows... Just create a new OpenGL context for each window and then use wglMakeCurrent and then swap the buffers and then repeat for each window.
Author
yeah, now works (it will work in LPS (=limited-planes system) mapeditor, i''ll release it soon). thank you all
(somebody please close this thread...) bye
(somebody please close this thread...) bye
the above two are right. my last renderer used 9 windows (VCL)
OpenGL renders in the selected context in the current thread.
If you have two windows and only need to rendere in one of them at a time, create a context for both and then use wglmakecurrent to select which you wish to render in.
if you want to have both windows being rendered into at the same time, you can either swap the current context between the two (a bit dodgey, but hey, it works) or you can do it the better way and create a two threads. In each thread you have a seperate opengl thread that renders to one of the windows.
Either way, under win32 OpenGL always renders into the THREADS current device context.
I have no idea about macos or os2 or solaris or linux or dos though. I never played with opengl that much under them.
OpenGL renders in the selected context in the current thread.
If you have two windows and only need to rendere in one of them at a time, create a context for both and then use wglmakecurrent to select which you wish to render in.
if you want to have both windows being rendered into at the same time, you can either swap the current context between the two (a bit dodgey, but hey, it works) or you can do it the better way and create a two threads. In each thread you have a seperate opengl thread that renders to one of the windows.
Either way, under win32 OpenGL always renders into the THREADS current device context.
I have no idea about macos or os2 or solaris or linux or dos though. I never played with opengl that much under them.
This topic is closed to new replies.
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