Hi,
After investigating a bit in the Wine code, it seems that the flickering bug of WoW in OpenGL mode is due to wglGetPbufferDCARB that returns a DC which type is OBJ_MEMDC while it should return a DC which type is OBJ_DC. And since in the current git tree, the DC type of a Pbuffer is OBJ_MEMDC then the code located in lines 1394-1395 of dlls/winex11.drv/opengl.c is executed : the Pbuffer is copied to the screen each time the GL context is made current to the Pbuffer hence the flickering (WoW bounds the GL context alternatively to the screen and to the Pbuffer). The expected behaviour is not to copy the Pbuffer content to the screen since WoW does it itself.
The easiest workaround for this bug would be to make X11DRV_wglGetPbufferDCARB to return the Pbuffer's object->hdc (this fixes the flickering bug). However, I have made some tests with Windows XP and it appears that wglGetPbufferDCARB returns a HDC different from the HDC passed when wglCreatePbufferARB was called. So such a patch would be a dirty hack not a real fix.
I am not familiar enough with Wine to submit a patch so I leave the gurus out there find an elegant solution.
Attached is the code that I used to perform a few tests about Pbuffers on Windows XP (code of interest is located from line 293 to line 298).
Regards,
Bertrand.
/* * This Code Was Created By Jeff Molofee 2000 * A HUGE Thanks To Fredric Echols For Cleaning Up * And Optimizing This Code, Making It More Flexible! * If You've Found This Code Useful, Please Let Me Know. * Visit My Site At nehe.gamedev.net */
#include <windows.h> // Header File For Windows #include <gl\gl.h> // Header File For The OpenGL32 Library #include <gl\glu.h> // Header File For The GLu32 Library #include <gl\glaux.h> // Header File For The Glaux Library
HDC hDC=NULL; // Private GDI Device Context HGLRC hRC=NULL; // Permanent Rendering Context HWND hWnd=NULL; // Holds Our Window Handle HINSTANCE hInstance; // Holds The Instance Of The Application
bool keys[256]; // Array Used For The Keyboard Routine bool active=TRUE; // Window Active Flag Set To TRUE By Default bool fullscreen=TRUE; // Fullscreen Flag Set To Fullscreen Mode By Default
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc
DECLARE_HANDLE(HPBUFFERARB);
typedef HPBUFFERARB (APIENTRY * wglCreatePbufferARB_t)(HDC hDC, int iPixelFormat, int iWidth, int iHeight, const int *piAttribList);
typedef HDC (APIENTRY * wglGetPbufferDCARB_t)(HPBUFFERARB hPbuffer);
typedef int (APIENTRY * wglReleasePbufferDCARB_t)(HPBUFFERARB hPbuffer, HDC hDC);
typedef BOOL (APIENTRY * wglDestroyPbufferARB_t)(HPBUFFERARB hPbuffer);
wglCreatePbufferARB_t wglCreatePbufferARB = NULL; wglGetPbufferDCARB_t wglGetPbufferDCARB = NULL; wglReleasePbufferDCARB_t wglReleasePbufferDCARB = NULL; wglDestroyPbufferARB_t wglDestroyPbufferARB = NULL;
GLvoid ReSizeGLScene(GLsizei width, GLsizei height) // Resize And Initialize The GL Window { if (height==0) // Prevent A Divide By Zero By { height=1; // Making Height Equal One }
glViewport(0,0,width,height); // Reset The Current Viewport
glMatrixMode(GL_PROJECTION); // Select The Projection Matrix glLoadIdentity(); // Reset The Projection Matrix
// Calculate The Aspect Ratio Of The Window gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix glLoadIdentity(); // Reset The Modelview Matrix }
int InitGL(GLvoid) // All Setup For OpenGL Goes Here { 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 return TRUE; // Initialization Went OK }
int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer glLoadIdentity(); // Reset The Current Modelview Matrix return TRUE; // Everything Went OK }
GLvoid KillGLWindow(GLvoid) // Properly Kill The Window { if (fullscreen) // Are We In Fullscreen Mode? { ChangeDisplaySettings(NULL,0); // If So Switch Back To The Desktop ShowCursor(TRUE); // Show Mouse Pointer }
if (hRC) // Do We Have A Rendering Context? { if (!wglMakeCurrent(NULL,NULL)) // Are We Able To Release The DC And RC Contexts? { MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); }
if (!wglDeleteContext(hRC)) // Are We Able To Delete The RC? { MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); } hRC=NULL; // Set RC To NULL }
if (hDC && !ReleaseDC(hWnd,hDC)) // Are We Able To Release The DC { MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hDC=NULL; // Set DC To NULL }
if (hWnd && !DestroyWindow(hWnd)) // Are We Able To Destroy The Window? { MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hWnd=NULL; // Set hWnd To NULL }
if (!UnregisterClass("OpenGL",hInstance)) // Are We Able To Unregister Class { MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hInstance=NULL; // Set hInstance To NULL } }
/* This Code Creates Our OpenGL Window. Parameters Are: * * title - Title To Appear At The Top Of The Window * * width - Width Of The GL Window Or Fullscreen Mode * * height - Height Of The GL Window Or Fullscreen Mode * * bits - Number Of Bits To Use For Color (8/16/24/32) * * fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE) */
BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag) { GLuint PixelFormat; // Holds The Results After Searching For A Match WNDCLASS wc; // Windows Class Structure DWORD dwExStyle; // Window Extended Style DWORD dwStyle; // Window Style RECT WindowRect; // Grabs Rectangle Upper Left / Lower Right Values WindowRect.left=(long)0; // Set Left Value To 0 WindowRect.right=(long)width; // Set Right Value To Requested Width WindowRect.top=(long)0; // Set Top Value To 0 WindowRect.bottom=(long)height; // Set Bottom Value To Requested Height
fullscreen=fullscreenflag; // Set The Global Fullscreen Flag
hInstance = GetModuleHandle(NULL); // Grab An Instance For Our Window wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window. wc.lpfnWndProc = (WNDPROC) WndProc; // WndProc Handles Messages wc.cbClsExtra = 0; // No Extra Window Data wc.cbWndExtra = 0; // No Extra Window Data wc.hInstance = hInstance; // Set The Instance wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer wc.hbrBackground = NULL; // No Background Required For GL wc.lpszMenuName = NULL; // We Don't Want A Menu wc.lpszClassName = "OpenGL"; // Set The Class Name
HPBUFFERARB pBuffer = NULL; #define WGL_PBUFFER_LARGEST_ARB 0x2033 int attrib[] = {WGL_PBUFFER_LARGEST_ARB, 0, 0}; BOOL success; HDC pBufferHDC; DWORD type1 = 0; DWORD type2 = 0; int result = 0xdeadbeef;
if (!RegisterClass(&wc)) // Attempt To Register The Window Class { MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if (fullscreen) // Attempt Fullscreen Mode? { DEVMODE dmScreenSettings; // Device Mode memset(&dmScreenSettings,0,sizeof(dmScreenSettings)); // Makes Sure Memory's Cleared dmScreenSettings.dmSize=sizeof(dmScreenSettings); // Size Of The Devmode Structure dmScreenSettings.dmPelsWidth = width; // Selected Screen Width dmScreenSettings.dmPelsHeight = height; // Selected Screen Height dmScreenSettings.dmBitsPerPel = bits; // Selected Bits Per Pixel dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;
// Try To Set Selected Mode And Get Results. NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar. if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL) { // If The Mode Fails, Offer Two Options. Quit Or Use Windowed Mode. if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES) { fullscreen=FALSE; // Windowed Mode Selected. Fullscreen = FALSE } else { // Pop Up A Message Box Letting User Know The Program Is Closing. MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP); return FALSE; // Return FALSE } } }
if (fullscreen) // Are We Still In Fullscreen Mode? { dwExStyle=WS_EX_APPWINDOW; // Window Extended Style dwStyle=WS_POPUP; // Windows Style ShowCursor(FALSE); // Hide Mouse Pointer } else { dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style dwStyle=WS_OVERLAPPEDWINDOW; // Windows Style }
AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust Window To True Requested Size
// Create The Window if (!(hWnd=CreateWindowEx( dwExStyle, // Extended Style For The Window "OpenGL", // Class Name title, // Window Title dwStyle | // Defined Window Style WS_CLIPSIBLINGS | // Required Window Style WS_CLIPCHILDREN, // Required Window Style 0, 0, // Window Position WindowRect.right-WindowRect.left, // Calculate Window Width WindowRect.bottom-WindowRect.top, // Calculate Window Height NULL, // No Parent Window NULL, // No Menu hInstance, // Instance NULL))) // Dont Pass Anything To WM_CREATE { KillGLWindow(); // Reset The Display MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
static PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format bits, // Select Our 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, // Accumulation Bits Ignored 16, // 16Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC=GetDC(hWnd))) // Did We Get A Device Context? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))) // Did Windows Find A Matching Pixel Format? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
if(!SetPixelFormat(hDC,PixelFormat,&pfd)) // Are We Able To Set The Pixel Format? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
if (!(hRC=wglCreateContext(hDC))) // Are We Able To Get A Rendering Context? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
if(!wglMakeCurrent(hDC,hRC)) // Try To Activate The Rendering Context { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
wglCreatePbufferARB = (wglCreatePbufferARB_t)wglGetProcAddress("wglCreatePbufferARB"); wglGetPbufferDCARB = (wglGetPbufferDCARB_t)wglGetProcAddress("wglGetPbufferDCARB"); wglReleasePbufferDCARB = (wglReleasePbufferDCARB_t)wglGetProcAddress("wglReleasePbufferDCARB"); wglDestroyPbufferARB = (wglDestroyPbufferARB_t)wglGetProcAddress("wglDestroyPbufferARB");
pBuffer = wglCreatePbufferARB(hDC, PixelFormat, width, height, attrib); pBufferHDC = wglGetPbufferDCARB(pBuffer); type1 = GetObjectType(hDC); type2 = GetObjectType(pBufferHDC); result = wglReleasePbufferDCARB(pBuffer, pBufferHDC); success = wglDestroyPbufferARB(pBuffer);
ShowWindow(hWnd,SW_SHOW); // Show The Window SetForegroundWindow(hWnd); // Slightly Higher Priority SetFocus(hWnd); // Sets Keyboard Focus To The Window ReSizeGLScene(width, height); // Set Up Our Perspective GL Screen
if (!InitGL()) // Initialize Our Newly Created GL Window { KillGLWindow(); // Reset The Display MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE }
return TRUE; // Success }
LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_ACTIVATE: // Watch For Window Activate Message { if (!HIWORD(wParam)) // Check Minimization State { active=TRUE; // Program Is Active } else { active=FALSE; // Program Is No Longer Active }
return 0; // Return To The Message Loop }
case WM_SYSCOMMAND: // Intercept System Commands { switch (wParam) // Check System Calls { case SC_SCREENSAVE: // Screensaver Trying To Start? case SC_MONITORPOWER: // Monitor Trying To Enter Powersave? return 0; // Prevent From Happening } break; // Exit }
case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back }
case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = TRUE; // If So, Mark It As TRUE return 0; // Jump Back }
case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = FALSE; // If So, Mark It As FALSE return 0; // Jump Back }
case WM_SIZE: // Resize The OpenGL Window { ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } }
// Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); }
int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure BOOL done=FALSE; // Bool Variable To Exit Loop
// Ask The User Which Screen Mode They Prefer if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO) { fullscreen=FALSE; // Windowed Mode }
// Create Our OpenGL Window if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen)) { return 0; // Quit If Window Was Not Created }
while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=TRUE; // If So done=TRUE } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { // Draw The Scene. Watch For ESC Key And Quit Messages From DrawGLScene() if (active) // Program Active? { if (keys[VK_ESCAPE]) // Was ESC Pressed? { done=TRUE; // ESC Signalled A Quit } else // Not Time To Quit, Update Screen { DrawGLScene(); // Draw The Scene SwapBuffers(hDC); // Swap Buffers (Double Buffering) } }
if (keys[VK_F1]) // Is F1 Being Pressed? { keys[VK_F1]=FALSE; // If So Make Key FALSE KillGLWindow(); // Kill Our Current Window fullscreen=!fullscreen; // Toggle Fullscreen / Windowed Mode // Recreate Our OpenGL Window if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen)) { return 0; // Quit If Window Was Not Created } } } }
// Shutdown KillGLWindow(); // Kill The Window return (msg.wParam); // Exit The Program }