outdated: 46.Fullscreen AntiAliasing
全屏抗锯齿通过采样算法，将图形边缘会造成锯齿的这些像素与其周围的像素作一个平均的运算，增加像素的数目以达到像素之间平滑过渡的效果，不过有的地方可能会显得模糊。使用了两个头文件的扩展，
#include <GL\wglext.h> // WGL extensions #include <GL\glext.h> // GL extwnsions
代码如下，抗锯齿的实现叫做多重采样。
bool WGLisExtensionSupported(const char* extension) { const size_t extlen = strlen(extension); const char* supported = NULL; // Try to use wglGetExtensionStringARB on cureent DC PROC wglGetExtString = wglGetProcAddress("wglGetExtensionsStringARB"); if (wglGetExtString) { supported = ((char*(__stdcall*)(HDC))wglGetExtString)(wglGetCurrentDC()); } // If that failed, try standard OpenGL extension string if (supported == NULL) { supported = (char*)glGetString(GL_EXTENSIONS); } // If that failed too, must be no extension supported if (supported == NULL) { return false; } // Begin examination at start of string, increment by 1 on false match for (const char* p = supported; ; ++p) { p = strstr(p, extension); if (p == NULL) { return false; } if ((p == supported || p[-1] == ' ') || (p[extlen] == '\0' || p[extlen] == ' ')) { return true; } } } bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf) { // The string exists in WGL if (!WGLisExtensionSupported("WGL_ARB_multisample")) { arbMultisampleSupported = false; return false; } // Get pixel format PFNWGLCHOOSEPIXELFORMATARBPROC wglChoosePixelFormatARB = (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB"); if (!wglChoosePixelFormatARB) { arbMultisampleSupported = false; return false; } // Get current device context HDC hDC = GetDC(hWnd); int pixelFormat; BOOL valid; UINT numFormats; float fAttributes[] = { 0, 0 }; // These attributes are the bits we want to test for in our sample int iAttributes[] = { WGL_DRAW_TO_WINDOW_ARB, GL_TRUE, WGL_SUPPORT_OPENGL_ARB,GL_TRUE, WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB, WGL_COLOR_BITS_ARB,24, WGL_ALPHA_BITS_ARB,8, WGL_DEPTH_BITS_ARB,16, WGL_STENCIL_BITS_ARB,0, WGL_DOUBLE_BUFFER_ARB,GL_TRUE, WGL_SAMPLE_BUFFERS_ARB,GL_TRUE, WGL_SAMPLES_ARB, 4 , 0,0 }; // Get a pixel format for 4 samples valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats); if (valid && numFormats >= 1) { arbMultisampleSupported = true; arbMultisampleFormat = pixelFormat; return arbMultisampleSupported; } iAttributes[19] = 2; valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats); if (valid && numFormats >= 1) { arbMultisampleSupported = true; arbMultisampleFormat = pixelFormat; return arbMultisampleSupported; } return arbMultisampleSupported; }
第一张图未开Multisampling，第二张图开了Multisampling，作为对比我们可以看到，特别是红色边缘，第二张图的锯齿明显多了很多。
下面为代码，
#ifndef GL_FRAMEWORK_INCLUDED #define GL_FRAMEWORK_INCLUDED #include <windows.h> typedef struct { // Structure for keyboard stuff BOOL keyDown[256]; } Keys; typedef struct { // Contains information vital to applications HMODULE hInstance; // Application Instance const char* className; } Application; typedef struct { // Window creation info Application* application; char* title; int width; int height; int bitsPerPixel; BOOL isFullScreen; } GL_WindowInit; typedef struct { // Contains information vital to a window Keys* keys; HWND hWnd; // Windows handle HDC hDC; // Device context HGLRC hRC; // Rendering context GL_WindowInit init; BOOL isVisible; // Window visiable? DWORD lastTickCount; // Tick counter } GL_Window; void TerminateApplication(GL_Window* window); // Terminate the application void ToggleFullscreen(GL_Window* window); // Toggle fullscreen / Windowed mode BOOL Initialize(GL_Window* window, Keys* keys); void Deinitialize(void); void Update(DWORD milliseconds); void Draw(void); #endif
#include <Windows.h> #include <GL\glew.h> #include <GL\glut.h> #include "Previous.h" #define WM_TOGGLEFULLSCREEN (WM_USER+1) // Application define message for toggling // between fulscreen / windowed mode static BOOL g_isProgramLooping; // Window creation loop, for fullscreen / windowed mode static BOOL g_createFullScreen; // If true, then create window void TerminateApplication(GL_Window* window) // Terminate the application { PostMessage(window->hWnd, WM_QUIT, 0, 0); // Send a WM_QUIT message g_isProgramLooping = FALSE; // Stop looping of the program } void ToggleFullscreen(GL_Window* window) // Toggle fullscreen /windowed mode { PostMessage(window->hWnd, WM_TOGGLEFULLSCREEN, 0, 0); // Send a WM_TOGGLEFULLSCREEN message } void ReshapeGL(int width, int height) // Reshape the window when it's moved or resized { glViewport(0, 0, (GLsizei)(width), (GLsizei)(height)); // Reset the current viewport glMatrixMode(GL_PROJECTION); glLoadIdentity(); // Calcutate the aspect ratio of the window gluPerspective(45.0f, (GLfloat)(width) / (GLfloat)(height), 1.0, 1000.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } BOOL ChangeScreenResolution(int width, int height, int bitsPerPixel) // Change the screen resolution { DEVMODE dmScreenSettings; // Device mode ZeroMemory(&dmScreenSettings, sizeof(DEVMODE)); // Make sure memory is cleared dmScreenSettings.dmSize = sizeof(DEVMODE); // Size of the devmode structure dmScreenSettings.dmPelsWidth = width; dmScreenSettings.dmPelsHeight = height; dmScreenSettings.dmBitsPerPel = bitsPerPixel; dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT; if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL) { return FALSE; // Display change failed } return TRUE; } BOOL CreateWindowGL(GL_Window* window) { DWORD windowStyle = WS_OVERLAPPEDWINDOW; // Define window style DWORD windowExtendedStyle = WS_EX_APPWINDOW; // Define the window's extended style PIXELFORMATDESCRIPTOR pdf = { 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 window->init.bitsPerPixel, // Select 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, // 16bits 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 }; RECT windowRect = { 0, 0, window->init.width, window->init.height }; // Window coordiantes GLuint PixelFormat; if (window->init.isFullScreen == TRUE) { if (ChangeScreenResolution(window->init.width, window->init.height, window->init.bitsPerPixel) == FALSE) { // Fullscreen mode failed, run in windowed mode instead MessageBox(HWND_DESKTOP, "Mode Switch Failed.\nRuning In Windowed Mode.", "Error", MB_OK | MB_ICONEXCLAMATION); window->init.isFullScreen = FALSE; } else { ShowCursor(FALSE); windowStyle = WS_POPUP; // Popup window windowExtendedStyle |= WS_EX_TOPMOST; } } else { // Adjust window, account for window borders AdjustWindowRectEx(&windowRect, windowStyle, 0, windowExtendedStyle); } // Create Opengl window window->hWnd = CreateWindowEx(windowExtendedStyle, // Extended style window->init.application->className, // Class name window->init.title, // Window title windowStyle, // Window style 0, 0, // Window X,Y position windowRect.right - windowRect.left, // Window width windowRect.bottom - windowRect.top, // Window height HWND_DESKTOP, // Desktop is window's parent 0, // No menu window->init.application->hInstance, // Pass the window instance window); if (window->hWnd == 0) { // Was window creation a success? return FALSE; } window->hDC = GetDC(window->hWnd); if (window->hDC == 0) { DestroyWindow(window->hWnd); window->hWnd = 0; return FALSE; } PixelFormat = ChoosePixelFormat(window->hDC, &pdf); // Find a compatible pixel format if (PixelFormat == 0) { ReleaseDC(window->hWnd, window->hDC); // Release device context window->hDC = 0; DestroyWindow(window->hWnd); window->hWnd = 0; return FALSE; } if (SetPixelFormat(window->hDC, PixelFormat, &pdf) == FALSE) { // Try to set the pixel format ReleaseDC(window->hWnd, window->hDC); window->hDC = 0; DestroyWindow(window->hWnd); window->hWnd = 0; return FALSE; } window->hRC = wglCreateContext(window->hDC); // Try to get a rendering context if (window->hRC == 0) { ReleaseDC(window->hWnd, window->hDC); window->hDC = 0; DestroyWindow(window->hWnd); window->hWnd = 0; return FALSE; } // Make the rendering context our current rendering context if (wglMakeCurrent(window->hDC, window->hRC) == FALSE) { wglDeleteContext(window->hRC); // Delete the rendering context window->hRC = 0; ReleaseDC(window->hWnd, window->hDC); window->hDC = 0; DestroyWindow(window->hWnd); window->hWnd = 0; return FALSE; } ShowWindow(window->hWnd, SW_NORMAL); // Make the window visiable window->isVisible = TRUE; ReshapeGL(window->init.width, window->init.height); // Reshape our GL window ZeroMemory(window->keys, sizeof(Keys)); // Clear all keys window->lastTickCount = GetTickCount(); return TRUE; } BOOL DestroyWindowGL(GL_Window* window) { if (window->hWnd != 0) { if (window->hDC != 0) { wglMakeCurrent(window->hDC, 0); // Setting current active rendering context to zero if (window->hRC != 0) { wglDeleteContext(window->hRC); window->hRC = 0; } ReleaseDC(window->hWnd, window->hDC); window->hDC = 0; } DestroyWindow(window->hWnd); window->hWnd = 0; } if (window->init.isFullScreen) { ChangeDisplaySettings(NULL, 0); // Switch back to desktop resolution ShowCursor(TRUE); } return TRUE; } // Process window message callback LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { // Get the window context GL_Window* window = (GL_Window*)(GetWindowLong(hWnd, GWL_USERDATA)); switch (uMsg) { // Evaluate window message case WM_SYSCOMMAND: // Intercept system commands { switch (wParam) { // Check system calls case SC_SCREENSAVE: // Screensaver trying to start? case SC_MONITORPOWER: // Mointer trying to enter powersave? return 0; // Prevent form happening } break; } return 0; case WM_CREATE: { CREATESTRUCT* creation = (CREATESTRUCT*)(lParam); // Store window structure pointer window = (GL_Window*)(creation->lpCreateParams); SetWindowLong(hWnd, GWL_USERDATA, (LONG)(window)); } return 0; case WM_CLOSE: TerminateApplication(window); return 0; case WM_SIZE: switch (wParam) { case SIZE_MINIMIZED: // Was window minimized? window->isVisible = FALSE; return 0; case SIZE_MAXIMIZED: window->isVisible = TRUE; ReshapeGL(LOWORD(lParam), HIWORD(lParam)); return 0; case SIZE_RESTORED: window->isVisible = TRUE; ReshapeGL(LOWORD(lParam), HIWORD(lParam)); return 0; } break; case WM_KEYDOWN: if ((wParam >= 0) && (wParam <= 255)) { window->keys->keyDown[wParam] = TRUE; // Set the selected key(wParam) to true return 0; } break; case WM_KEYUP: if ((wParam >= 0) && (wParam <= 255)) { window->keys->keyDown[wParam] = FALSE; return 0; } break; case WM_TOGGLEFULLSCREEN: g_createFullScreen = (g_createFullScreen == TRUE) ? FALSE : TRUE; PostMessage(hWnd, WM_QUIT, 0, 0); break; } return DefWindowProc(hWnd, uMsg, wParam, lParam); // Pass unhandle message to DefWindowProc } BOOL RegisterWindowClass(Application* application) { WNDCLASSEX windowClass; ZeroMemory(&windowClass, sizeof(WNDCLASSEX)); // Make sure memory is cleared windowClass.cbSize = sizeof(WNDCLASSEX); // Size of the windowClass structure windowClass.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraws the window for any movement / resizing windowClass.lpfnWndProc = (WNDPROC)(WindowProc); // WindowProc handles message windowClass.hInstance = application->hInstance; // Set the instance windowClass.hbrBackground = (HBRUSH)(COLOR_APPWORKSPACE);// Class background brush color windowClass.hCursor = LoadCursor(NULL, IDC_ARROW); // Load the arrow pointer windowClass.lpszClassName = application->className; // Sets the application className if (RegisterClassEx(&windowClass) == 0) { MessageBox(HWND_DESKTOP, "RegisterClassEx Failed!", "Error", MB_OK | MB_ICONEXCLAMATION); return FALSE; } return TRUE; } int WINAPI WinMain(HINSTANCE hIstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { Application application; GL_Window window; Keys keys; BOOL isMessagePumpActive; MSG msg; DWORD tickCount; application.className = "OpenGL"; application.hInstance = hIstance; ZeroMemory(&window, sizeof(GL_Window)); window.keys = &keys; // Window key structure window.init.application = &application; // Window application window.init.title = "Resource File"; // Window title window.init.width = 640; // Window width window.init.height = 480; // Window height window.init.bitsPerPixel = 16; // Bits per pixel window.init.isFullScreen = TRUE; // Fullscreen? (set to TRUE) ZeroMemory(&keys, sizeof(Keys)); if (MessageBox(HWND_DESKTOP, "Would You Like To Run In Fullscreen Mode?", "Start FullScreen?", MB_YESNO | MB_ICONQUESTION) == IDNO) { window.init.isFullScreen = FALSE; } if (RegisterWindowClass(&application) == FALSE) { MessageBox(HWND_DESKTOP, "Error Registering Window Class!", "Error", MB_OK | MB_ICONEXCLAMATION); return -1; } g_isProgramLooping = TRUE; g_createFullScreen = window.init.isFullScreen; while (g_isProgramLooping) { // Loop until WM_QUIT is received window.init.isFullScreen = g_createFullScreen; // Set init param of window creation to fullscreen? if (CreateWindowGL(&window) == TRUE) { // Was window creation successful? // At this point we should have a window that is setup to render OpenGL if (Initialize(&window, &keys) == FALSE) { TerminateApplication(&window); // Close window, this will handle the shutdown } else { isMessagePumpActive = TRUE; while (isMessagePumpActive == TRUE) { // Success creating window. Check for window messages if (PeekMessage(&msg, window.hWnd, 0, 0, PM_REMOVE) != 0) { if (msg.message != WM_QUIT) { DispatchMessage(&msg); } else { isMessagePumpActive = FALSE; // Terminate the message pump } } else { if (window.isVisible == FALSE) { WaitMessage(); // Application is minimized wait for a message } else { // Process application loop tickCount = GetTickCount(); // Get the tick count Update(tickCount - window.lastTickCount); // Update the counter window.lastTickCount = tickCount;// Set last count to current count Draw(); // Draw screen SwapBuffers(window.hDC); } } } } // Application is finished Deinitialize(); DestroyWindowGL(&window); } else { MessageBox(HWND_DESKTOP, "Error Creating OpenGL Window", "Error", MB_OK | MB_ICONEXCLAMATION); g_isProgramLooping = FALSE; } } UnregisterClass(application.className, application.hInstance); // UnRegister window class return 0; }
#ifndef __ARB_MULTISAMPLE_H__ #define __ARB_MULTISAMPLE_H__ #include <GL\wglext.h> // WGL extensions #include <GL\glext.h> // GL extwnsions // Globals extern bool arbMultisampleSupported; extern int arbMultisampleFormat; // If you don't want multisampling, set this to 0 #define CHECK_FOR_MULTISAMPLE 1 // To heck for our sampling bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf); #endif // !__ARB_MULTISAMPLE_H__
#include <Windows.h> #include <GL\glew.h> #include <GL\glut.h> #include "arbMultiSample.h" #define WGL_SAMPLE_BUFFERS_ARB 0X2041 #define WGL_SAMPLES_ARB 0x2042 bool arbMultisampleSupported = false; int arbMultisampleFormat = 0; bool WGLisExtensionSupported(const char* extension) { const size_t extlen = strlen(extension); const char* supported = NULL; // Try to use wglGetExtensionStringARB on cureent DC PROC wglGetExtString = wglGetProcAddress("wglGetExtensionStringARB"); if (wglGetExtString) { supported = ((char*(__stdcall*)(HDC))wglGetExtString)(wglGetCurrentDC()); } // If that failed, try standard OpenGL extension string if (supported == NULL) { supported = (char*)glGetString(GL_EXTENSIONS); } // If that failed too, must be no extension supported if (supported == NULL) { return false; } // Begin examination at start of string, increment by 1 on false match for (const char* p = supported; ; ++p) { p = strstr(p, extension); if (p == NULL) { return false; } if ((p == supported || p[-1] == ' ') || (p[extlen] == '\0' || p[extlen] == ' ')) { return true; } } } bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf) { // The string exists in WGL if (!WGLisExtensionSupported("WGL_ARB_multisample")) { arbMultisampleSupported = false; return false; } // Get pixel format PFNWGLCHOOSEPIXELFORMATARBPROC wglChoosePixelFormatARB = (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB"); if (!wglChoosePixelFormatARB) { arbMultisampleSupported = false; return false; } // Get current device context HDC hDC = GetDC(hWnd); int pixelFormat; BOOL valid; UINT numFormats; float fAttributes[] = { 0, 0 }; // These attributes are the bits we want to test for in our sample int iAttributes[] = { WGL_DRAW_TO_WINDOW_ARB, GL_TRUE, WGL_SUPPORT_OPENGL_ARB,GL_TRUE, WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB, WGL_COLOR_BITS_ARB,24, WGL_ALPHA_BITS_ARB,8, WGL_DEPTH_BITS_ARB,16, WGL_STENCIL_BITS_ARB,0, WGL_DOUBLE_BUFFER_ARB,GL_TRUE, WGL_SAMPLE_BUFFERS_ARB,GL_TRUE, WGL_SAMPLES_ARB, 4 , 0,0 }; // Get a pixel format for 4 samples valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats); if (valid && numFormats >= 1) { arbMultisampleSupported = true; arbMultisampleFormat = pixelFormat; return arbMultisampleSupported; } iAttributes[19] = 2; valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats); if (valid && numFormats >= 1) { arbMultisampleSupported = true; arbMultisampleFormat = pixelFormat; return arbMultisampleSupported; } return arbMultisampleSupported; }
#include <windows.h> #include <stdio.h> #include <math.h> #include <gl/glew.h> #include <gl/glut.h> #include <GL/GLUAX.H> #include <mmsystem.h> #include "Previous.h" #include "arbMultiSample.h" // Fullscreen AntiAliasing #pragma comment(lib, "legacy_stdio_definitions.lib") #ifndef CDS_FULLSCREEN #define CDS_FULLSCREEN 4 #endif bool domulti = true; bool doangle = true; float angle = 0.0f; GL_Window* g_window; Keys* g_keys; BOOL Initialize(GL_Window* window, Keys* keys) { g_window = window; g_keys = keys; angle = 0.0f; glViewport(0, 0, window->init.width, window->init.height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(50, (float)window->init.width / (float)window->init.height, 5, 2000); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glEnable(GL_DEPTH_TEST); glShadeModel(GL_SMOOTH); glClearColor(0.0f, 0.0f, 0.0f, 0.5f); return TRUE; } void Deinitialize(void) { } void Update(DWORD milliseconds) { if (g_keys->keyDown[VK_ESCAPE] == TRUE) { TerminateApplication(g_window); } if (g_keys->keyDown[VK_F1] == TRUE) { ToggleFullscreen(g_window); } if (g_keys->keyDown[VK_SPACE] == TRUE) { domulti = !domulti; } if (g_keys->keyDown['M'] == TRUE) { doangle = !doangle; } } void Draw(void) { if (domulti) { glEnable(GL_MULTISAMPLE_ARB); } glClearColor(0.0f, 0.0f, 0.0f, 0.5); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); for (float i = -10; i < 10; ++i) { for (float j = -10; j < 10; ++j) { glPushMatrix(); glTranslatef(i * 2.0f, j * 2.0f, -5.0f); glRotatef(angle, 0.0f, 0.0f, 1.0f); glBegin(GL_QUADS); glColor3f(1.0f, 0.0f, 0.0f); glVertex3f(i, j, 0.0f); glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(i + 2.0f, j, 0.0f); glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(i + 2.0f, j + 2.0f, 0.0f); glColor3f(1.0f, 1.0f, 1.0f); glVertex3f(i, j + 2.0f, 0.0f); glEnd(); glPopMatrix(); } } if (doangle) { angle += 0.05f; } glFlush(); if (domulti) { glDisable(GL_MULTISAMPLE_ARB); } }
Thanks for Nehe's tutorials, this is his home.
