src/wgl/wglutil.c

   1 /*
   2  * Author: kenc
   3  *
   4  * Created: March 1, 2013
   5  * Copyright    (c) 2013, Attachmate Corporation All Rights Reserved
   6  */
   7 #include <windows.h>
   8 #include <assert.h>
   9 #include <GL/gl.h>
  10 #include "wglutil.h"
  11
  12 #define STYLE                   WS_OVERLAPPEDWINDOW
  13 #define EXSTYLE                 WS_EX_OVERLAPPEDWINDOW
  14 #define GL_CLASS                "GL"
  15
  16 static PFNWGLMAKECONTEXTCURRENTARBPROC WGLMakeContextCurrent = NULL;
  17 static PFNWGLCHOOSEPIXELFORMATARBPROC WGLChoosePixelFormat = NULL;
  18
  19 LRESULT
  20 storeDC(HWND hWnd)
  21 {
  22         HDC hDC;
  23
  24         if ((hDC = GetDC(hWnd)) != NULL) {
  25                 SetWindowLongPtr(hWnd, GWLP_USERDATA, (LONG_PTR)hDC);
  26
  27                 assert(GetWindowLongPtr(hWnd, GWLP_USERDATA) == (LONG_PTR)hDC);
  28                 return 0;
  29         }
  30         return -1;
  31 }
  32
  33 HDC
  34 fetchDC(HWND hWnd)
  35 {
  36         assert(hWnd != NULL);
  37         if (hWnd != NULL) {
  38                 HDC hDC = (HDC)(INT_PTR)GetWindowLongPtr(hWnd, GWLP_USERDATA);
  39
  40                 assert(hDC != NULL);
  41                 return hDC;
  42         }
  43         return NULL;
  44 }
  45
  46 HWND
  47 getWindow(HINSTANCE hInst, int x, int y, int w, int h, int format)
  48 {
  49         HWND hParent;
  50
  51         if ((hParent = GetDesktopWindow()) != NULL) {
  52                 HWND hWnd = CreateWindowEx(EXSTYLE, GL_CLASS, "wincopy", STYLE, x, y, w, h, hParent, NULL, hInst, NULL);
  53                 HDC hDC;
  54                 BOOL ret;
  55
  56                 assert(hWnd != NULL);
  57                 if ((hDC = (HDC)(INT_PTR)GetWindowLongPtr(hWnd, GWLP_USERDATA)) != NULL) {
  58                         PIXELFORMATDESCRIPTOR pfd;
  59
  60                         if ((ret = SetPixelFormat(hDC, format, &pfd)) != FALSE)
  61                                 return hWnd;
  62                         ret = DestroyWindow(hWnd);
  63                         assert(ret != FALSE);
  64                 }
  65         }
  66         assert(hParent != NULL);
  67         return NULL;
  68 }
  69
  70 static int
  71 getFormat(HDC hDC, PIXELFORMATDESCRIPTOR *pfd)
  72 {
  73         int format;
  74
  75         int size = sizeof(PIXELFORMATDESCRIPTOR);
  76         memset(pfd, 0, size);
  77         pfd->nSize = size;
  78         pfd->nVersion = 1;
  79         pfd->dwFlags = PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL;
  80         pfd->iLayerType = PFD_MAIN_PLANE;
  81         pfd->iPixelType = PFD_TYPE_RGBA;
  82         format = ChoosePixelFormat(hDC, pfd);
  83         assert(format > 0);
  84         return format;
  85 }
  86
  87 static HGLRC
  88 createCurrentContext(HDC hDC)
  89 {
  90         HGLRC hGLRC = NULL;
  91
  92         if ((hGLRC = wglCreateContext(hDC)) != NULL) {
  93                 BOOL current;
  94
  95                 if ((current = wglMakeCurrent(hDC, hGLRC)) == FALSE) {
  96                         BOOL ret = wglDeleteContext(hGLRC);
  97
  98                         assert(ret != FALSE);
  99                         hGLRC = NULL;
 100                 }
 101         }
 102         else
 103                 assert(hGLRC != NULL);
 104         return hGLRC;
 105 }
 106
 107 static BOOL
 108 checkWGLExtensions(HINSTANCE hInst)
 109 {
 110         HWND hWnd;
 111         BOOL rval, ret = FALSE;
 112
 113         if ((hWnd = CreateWindowEx(EXSTYLE, GL_CLASS, "tmp", STYLE, 0, 0, 1, 1,
 114                 GetDesktopWindow(), NULL, hInst, NULL)) != NULL) {
 115                 HDC hDC;
 116
 117                 if ((hDC = fetchDC(hWnd)) != NULL) {
 118                         PIXELFORMATDESCRIPTOR pfd;
 119                         int format;
 120
 121                         if ((format = getFormat(hDC, &pfd)) > 0) {
 122                                 BOOL setFormat;
 123
 124                                 if ((setFormat = SetPixelFormat(hDC, format, &pfd)) != FALSE) {
 125                                         HGLRC hGLRC = createCurrentContext(hDC);
 126
 127                                         if (hGLRC != NULL) {
 128                                                 PFNWGLGETEXTENSIONSSTRINGPROC WGLGetExtensionsStringFunc;
 129
 130                                                 WGLGetExtensionsStringFunc = (PFNWGLGETEXTENSIONSSTRINGPROC)wglGetProcAddress("wglGetExtensionsStringARB");
 131                                                 assert(WGLGetExtensionsStringFunc != NULL);
 132                                                 if (WGLGetExtensionsStringFunc != NULL) {
 133                                                         const char *wglExtensionString = (*WGLGetExtensionsStringFunc)(hDC);
 134
 135                                                         if (wglExtensionString != NULL) {
 136                                                                 WGLMakeContextCurrent = (PFNWGLMAKECONTEXTCURRENTARBPROC)wglGetProcAddress("wglMakeContextCurrentARB");
 137                                                                 assert(WGLMakeContextCurrent != NULL);
 138                                                                 WGLChoosePixelFormat = (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB");
 139                                                                 assert(WGLChoosePixelFormat != NULL);
 140                                                                 if (WGLMakeContextCurrent != NULL && WGLChoosePixelFormat != NULL)
 141                                                                         ret = TRUE;
 142                                                         }
 143                                                 }
 144                                                 rval = wglDeleteContext(hGLRC);
 145                                                 assert(rval != FALSE);
 146                                         }
 147                                 }
 148                         }
 149                 }
 150                 rval = DestroyWindow(hWnd);
 151                 assert(rval != FALSE);
 152         }
 153         return ret;
 154 }
 155
 156
 157 BOOL
 158 wglExtInit(HINSTANCE hInst, WNDPROC proc)
 159 {
 160         WNDCLASS glClass;
 161         ATOM atom;
 162
 163         memset(&glClass, 0, sizeof(WNDCLASS));
 164         glClass.style = CS_PARENTDC;
 165         glClass.lpfnWndProc = proc;
 166         glClass.hInstance = hInst;
 167         glClass.lpszClassName = GL_CLASS;
 168         glClass.cbWndExtra = sizeof(HANDLE);
 169         if ((atom = RegisterClass(&glClass)) == 0) {
 170                 assert(atom != 0);
 171                 return FALSE;
 172         }
 173         return checkWGLExtensions(hInst);
 174 }
 175
 176 void
 177 wglExtDispose(HINSTANCE hInst)
 178 {
 179         BOOL ret;
 180
 181         ret = UnregisterClass(GL_CLASS, hInst);
 182         assert(ret != FALSE);
 183 }
 184
 185 BOOL
 186 wglExtMakeContextCurrent(HWND did, HWND rid, HGLRC gid)
 187 {
 188         HDC hDrawDC;
 189         BOOL ret = FALSE;
 190
 191         if ((hDrawDC = (HDC)(INT_PTR)GetWindowLongPtr(did, GWLP_USERDATA)) != NULL) {
 192                 if (did != rid) {
 193                         HDC hReadDC;
 194
 195                         if ((hReadDC = (HDC)(INT_PTR)GetWindowLongPtr(rid, GWLP_USERDATA)) != NULL) {
 196                                 ret = (*WGLMakeContextCurrent)(hDrawDC, hReadDC, gid);
 197                                 assert(ret != FALSE);
 198                         }
 199                 }
 200                 else
 201                         ret = wglMakeCurrent(hDrawDC, gid);
 202         }
 203         assert(ret != FALSE);
 204         return ret;
 205 }
 206
 207 BOOL
 208 wglExtSwapBuffers(HWND hWnd)
 209 {
 210         HDC hDC;
 211
 212         if ((hDC = (HDC)(INT_PTR)GetWindowLongPtr(hWnd, GWLP_USERDATA)) != NULL);
 213                 return wglSwapLayerBuffers(hDC, WGL_SWAP_MAIN_PLANE);
 214         return FALSE;
 215 }
 216
 217 int
 218 wglExtChoosePixelFormat(const int *attrs)
 219 {
 220         HDC hDC;
 221         HWND hWnd = GetDesktopWindow();
 222
 223         if ((hDC = (HDC)GetDC(hWnd)) != NULL) {
 224                 int format = 0;
 225                 UINT nFormats;
 226                 BOOL ret;
 227
 228                 WGLChoosePixelFormat(hDC, attrs, NULL, 1, &format, &nFormats);
 229                 assert(nFormats > 0 && format != 0);
 230                 ret = ReleaseDC(hWnd, hDC);
 231                 assert(ret != FALSE);
 232                 return format;
 233         }
 234         return 0;
 235 }