michael@0: 
michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkWGL.h"
michael@0: 
michael@0: #include "SkTDArray.h"
michael@0: #include "SkTSearch.h"
michael@0: #include "SkTSort.h"
michael@0: 
michael@0: bool SkWGLExtensions::hasExtension(HDC dc, const char* ext) const {
michael@0:     if (NULL == this->fGetExtensionsString) {
michael@0:         return false;
michael@0:     }
michael@0:     if (!strcmp("WGL_ARB_extensions_string", ext)) {
michael@0:         return true;
michael@0:     }
michael@0:     const char* extensionString = this->getExtensionsString(dc);
michael@0:     size_t extLength = strlen(ext);
michael@0: 
michael@0:     while (true) {
michael@0:         size_t n = strcspn(extensionString, " ");
michael@0:         if (n == extLength && 0 == strncmp(ext, extensionString, n)) {
michael@0:             return true;
michael@0:         }
michael@0:         if (0 == extensionString[n]) {
michael@0:             return false;
michael@0:         }
michael@0:         extensionString += n+1;
michael@0:     }
michael@0: 
michael@0:     return false;
michael@0: }
michael@0: 
michael@0: const char* SkWGLExtensions::getExtensionsString(HDC hdc) const {
michael@0:     return fGetExtensionsString(hdc);
michael@0: }
michael@0: 
michael@0: BOOL SkWGLExtensions::choosePixelFormat(HDC hdc,
michael@0:                                         const int* piAttribIList,
michael@0:                                         const FLOAT* pfAttribFList,
michael@0:                                         UINT nMaxFormats,
michael@0:                                         int* piFormats,
michael@0:                                         UINT* nNumFormats) const {
michael@0:     return fChoosePixelFormat(hdc, piAttribIList, pfAttribFList,
michael@0:                               nMaxFormats, piFormats, nNumFormats);
michael@0: }
michael@0: 
michael@0: BOOL SkWGLExtensions::getPixelFormatAttribiv(HDC hdc,
michael@0:                                              int iPixelFormat,
michael@0:                                              int iLayerPlane,
michael@0:                                              UINT nAttributes,
michael@0:                                              const int *piAttributes,
michael@0:                                              int *piValues) const {
michael@0:     return fGetPixelFormatAttribiv(hdc, iPixelFormat, iLayerPlane,
michael@0:                                    nAttributes, piAttributes, piValues);
michael@0: }
michael@0: 
michael@0: BOOL SkWGLExtensions::getPixelFormatAttribfv(HDC hdc,
michael@0:                                              int iPixelFormat,
michael@0:                                              int iLayerPlane,
michael@0:                                              UINT nAttributes,
michael@0:                                              const int *piAttributes,
michael@0:                                              float *pfValues) const {
michael@0:     return fGetPixelFormatAttribfv(hdc, iPixelFormat, iLayerPlane,
michael@0:                                    nAttributes, piAttributes, pfValues);
michael@0: }
michael@0: HGLRC SkWGLExtensions::createContextAttribs(HDC hDC,
michael@0:                                             HGLRC hShareContext,
michael@0:                                             const int *attribList) const {
michael@0:     return fCreateContextAttribs(hDC, hShareContext, attribList);
michael@0: }
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: struct PixelFormat {
michael@0:     int fFormat;
michael@0:     int fSampleCnt;
michael@0:     int fChoosePixelFormatRank;
michael@0: };
michael@0: 
michael@0: bool pf_less(const PixelFormat& a, const PixelFormat& b) {
michael@0:     if (a.fSampleCnt < b.fSampleCnt) {
michael@0:         return true;
michael@0:     } else if (b.fSampleCnt < a.fSampleCnt) {
michael@0:         return false;
michael@0:     } else if (a.fChoosePixelFormatRank < b.fChoosePixelFormatRank) {
michael@0:         return true;
michael@0:     }
michael@0:     return false;
michael@0: }
michael@0: }
michael@0: 
michael@0: int SkWGLExtensions::selectFormat(const int formats[],
michael@0:                                   int formatCount,
michael@0:                                   HDC dc,
michael@0:                                   int desiredSampleCount) {
michael@0:     PixelFormat desiredFormat = {
michael@0:         0,
michael@0:         desiredSampleCount,
michael@0:         0,
michael@0:     };
michael@0:     SkTDArray<PixelFormat> rankedFormats;
michael@0:     rankedFormats.setCount(formatCount);
michael@0:     for (int i = 0; i < formatCount; ++i) {
michael@0:         static const int kQueryAttr = SK_WGL_SAMPLES;
michael@0:         int numSamples;
michael@0:         this->getPixelFormatAttribiv(dc,
michael@0:                                      formats[i],
michael@0:                                      0,
michael@0:                                      1,
michael@0:                                      &kQueryAttr,
michael@0:                                      &numSamples);
michael@0:         rankedFormats[i].fFormat =  formats[i];
michael@0:         rankedFormats[i].fSampleCnt = numSamples;
michael@0:         rankedFormats[i].fChoosePixelFormatRank = i;
michael@0:     }
michael@0:     SkTQSort(rankedFormats.begin(),
michael@0:              rankedFormats.begin() + rankedFormats.count() - 1,
michael@0:              SkTLessFunctionToFunctorAdaptor<PixelFormat, pf_less>());
michael@0:     int idx = SkTSearch<PixelFormat, pf_less>(rankedFormats.begin(),
michael@0:                                               rankedFormats.count(),
michael@0:                                               desiredFormat,
michael@0:                                               sizeof(PixelFormat));
michael@0:     if (idx < 0) {
michael@0:         idx = ~idx;
michael@0:     }
michael@0:     return rankedFormats[idx].fFormat;
michael@0: }
michael@0: 
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: #if defined(UNICODE)
michael@0:     #define STR_LIT(X) L## #X
michael@0: #else
michael@0:     #define STR_LIT(X) #X
michael@0: #endif
michael@0: 
michael@0: #define DUMMY_CLASS STR_LIT("DummyClass")
michael@0: 
michael@0: HWND create_dummy_window() {
michael@0:     HMODULE module = GetModuleHandle(NULL);
michael@0:     HWND dummy;
michael@0:     RECT windowRect;
michael@0:     windowRect.left = 0;
michael@0:     windowRect.right = 8;
michael@0:     windowRect.top = 0;
michael@0:     windowRect.bottom = 8;
michael@0: 
michael@0:     WNDCLASS wc;
michael@0: 
michael@0:     wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
michael@0:     wc.lpfnWndProc = (WNDPROC) DefWindowProc;
michael@0:     wc.cbClsExtra = 0;
michael@0:     wc.cbWndExtra = 0;
michael@0:     wc.hInstance = module;
michael@0:     wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);
michael@0:     wc.hCursor = LoadCursor(NULL, IDC_ARROW);
michael@0:     wc.hbrBackground = NULL;
michael@0:     wc.lpszMenuName = NULL;
michael@0:     wc.lpszClassName = DUMMY_CLASS;
michael@0: 
michael@0:     if(!RegisterClass(&wc)) {
michael@0:         return 0;
michael@0:     }
michael@0: 
michael@0:     DWORD style, exStyle;
michael@0:     exStyle = WS_EX_CLIENTEDGE;
michael@0:     style = WS_SYSMENU;
michael@0: 
michael@0:     AdjustWindowRectEx(&windowRect, style, false, exStyle);
michael@0:     if(!(dummy = CreateWindowEx(exStyle,
michael@0:                                 DUMMY_CLASS,
michael@0:                                 STR_LIT("DummyWindow"),
michael@0:                                 WS_CLIPSIBLINGS | WS_CLIPCHILDREN | style,
michael@0:                                 0, 0,
michael@0:                                 windowRect.right-windowRect.left,
michael@0:                                 windowRect.bottom-windowRect.top,
michael@0:                                 NULL, NULL,
michael@0:                                 module,
michael@0:                                 NULL))) {
michael@0:         UnregisterClass(DUMMY_CLASS, module);
michael@0:         return NULL;
michael@0:     }
michael@0:     ShowWindow(dummy, SW_HIDE);
michael@0: 
michael@0:     return dummy;
michael@0: }
michael@0: 
michael@0: void destroy_dummy_window(HWND dummy) {
michael@0:     DestroyWindow(dummy);
michael@0:     HMODULE module = GetModuleHandle(NULL);
michael@0:     UnregisterClass(DUMMY_CLASS, module);
michael@0: }
michael@0: }
michael@0: 
michael@0: #define GET_PROC(NAME, SUFFIX) f##NAME = \
michael@0:                      (##NAME##Proc) wglGetProcAddress("wgl" #NAME #SUFFIX)
michael@0: 
michael@0: SkWGLExtensions::SkWGLExtensions()
michael@0:     : fGetExtensionsString(NULL)
michael@0:     , fChoosePixelFormat(NULL)
michael@0:     , fGetPixelFormatAttribfv(NULL)
michael@0:     , fGetPixelFormatAttribiv(NULL)
michael@0:     , fCreateContextAttribs(NULL) {
michael@0:     HDC prevDC = wglGetCurrentDC();
michael@0:     HGLRC prevGLRC = wglGetCurrentContext();
michael@0: 
michael@0:     PIXELFORMATDESCRIPTOR dummyPFD;
michael@0: 
michael@0:     ZeroMemory(&dummyPFD, sizeof(dummyPFD));
michael@0:     dummyPFD.nSize = sizeof(dummyPFD);
michael@0:     dummyPFD.nVersion = 1;
michael@0:     dummyPFD.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL;
michael@0:     dummyPFD.iPixelType = PFD_TYPE_RGBA;
michael@0:     dummyPFD.cColorBits  = 32;
michael@0:     dummyPFD.cDepthBits  = 0;
michael@0:     dummyPFD.cStencilBits = 8;
michael@0:     dummyPFD.iLayerType = PFD_MAIN_PLANE;
michael@0:     HWND dummyWND = create_dummy_window();
michael@0:     if (dummyWND) {
michael@0:         HDC dummyDC = GetDC(dummyWND);
michael@0:         int dummyFormat = ChoosePixelFormat(dummyDC, &dummyPFD);
michael@0:         SetPixelFormat(dummyDC, dummyFormat, &dummyPFD);
michael@0:         HGLRC dummyGLRC = wglCreateContext(dummyDC);
michael@0:         SkASSERT(dummyGLRC);
michael@0:         wglMakeCurrent(dummyDC, dummyGLRC);
michael@0: 
michael@0:         GET_PROC(GetExtensionsString, ARB);
michael@0:         GET_PROC(ChoosePixelFormat, ARB);
michael@0:         GET_PROC(GetPixelFormatAttribiv, ARB);
michael@0:         GET_PROC(GetPixelFormatAttribfv, ARB);
michael@0:         GET_PROC(CreateContextAttribs, ARB);
michael@0: 
michael@0:         wglMakeCurrent(dummyDC, NULL);
michael@0:         wglDeleteContext(dummyGLRC);
michael@0:         destroy_dummy_window(dummyWND);
michael@0:     }
michael@0: 
michael@0:     wglMakeCurrent(prevDC, prevGLRC);
michael@0: }
michael@0: 
michael@0: HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool preferCoreProfile) {
michael@0:     SkWGLExtensions extensions;
michael@0:     if (!extensions.hasExtension(dc, "WGL_ARB_pixel_format")) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     HDC prevDC = wglGetCurrentDC();
michael@0:     HGLRC prevGLRC = wglGetCurrentContext();
michael@0:     PIXELFORMATDESCRIPTOR pfd;
michael@0: 
michael@0:     int format = 0;
michael@0: 
michael@0:     static const int iAttrs[] = {
michael@0:         SK_WGL_DRAW_TO_WINDOW, TRUE,
michael@0:         SK_WGL_DOUBLE_BUFFER, TRUE,
michael@0:         SK_WGL_ACCELERATION, SK_WGL_FULL_ACCELERATION,
michael@0:         SK_WGL_SUPPORT_OPENGL, TRUE,
michael@0:         SK_WGL_COLOR_BITS, 24,
michael@0:         SK_WGL_ALPHA_BITS, 8,
michael@0:         SK_WGL_STENCIL_BITS, 8,
michael@0:         0, 0
michael@0:     };
michael@0: 
michael@0:     float fAttrs[] = {0, 0};
michael@0: 
michael@0:     if (msaaSampleCount > 0 &&
michael@0:         extensions.hasExtension(dc, "WGL_ARB_multisample")) {
michael@0:         static const int kIAttrsCount = SK_ARRAY_COUNT(iAttrs);
michael@0:         int msaaIAttrs[kIAttrsCount + 4];
michael@0:         memcpy(msaaIAttrs, iAttrs, sizeof(int) * kIAttrsCount);
michael@0:         SkASSERT(0 == msaaIAttrs[kIAttrsCount - 2] &&
michael@0:                  0 == msaaIAttrs[kIAttrsCount - 1]);
michael@0:         msaaIAttrs[kIAttrsCount - 2] = SK_WGL_SAMPLE_BUFFERS;
michael@0:         msaaIAttrs[kIAttrsCount - 1] = TRUE;
michael@0:         msaaIAttrs[kIAttrsCount + 0] = SK_WGL_SAMPLES;
michael@0:         msaaIAttrs[kIAttrsCount + 1] = msaaSampleCount;
michael@0:         msaaIAttrs[kIAttrsCount + 2] = 0;
michael@0:         msaaIAttrs[kIAttrsCount + 3] = 0;
michael@0:         unsigned int num;
michael@0:         int formats[64];
michael@0:         extensions.choosePixelFormat(dc, msaaIAttrs, fAttrs, 64, formats, &num);
michael@0:         num = SkTMin(num, 64U);
michael@0:         int formatToTry = extensions.selectFormat(formats,
michael@0:                                                   num,
michael@0:                                                   dc,
michael@0:                                                   msaaSampleCount);
michael@0:         DescribePixelFormat(dc, formatToTry, sizeof(pfd), &pfd);
michael@0:         if (SetPixelFormat(dc, formatToTry, &pfd)) {
michael@0:             format = formatToTry;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (0 == format) {
michael@0:         // Either MSAA wasn't requested or creation failed
michael@0:         unsigned int num;
michael@0:         extensions.choosePixelFormat(dc, iAttrs, fAttrs, 1, &format, &num);
michael@0:         DescribePixelFormat(dc, format, sizeof(pfd), &pfd);
michael@0:         SkDEBUGCODE(BOOL set =) SetPixelFormat(dc, format, &pfd);
michael@0:         SkASSERT(TRUE == set);
michael@0:     }
michael@0: 
michael@0:     HGLRC glrc = NULL;
michael@0:     if (preferCoreProfile && extensions.hasExtension(dc, "WGL_ARB_create_context")) {
michael@0:         static const int kCoreGLVersions[] = {
michael@0:             4, 3,
michael@0:             4, 2,
michael@0:             4, 1,
michael@0:             4, 0,
michael@0:             3, 3,
michael@0:             3, 2,
michael@0:         };
michael@0:         int coreProfileAttribs[] = {
michael@0:             SK_WGL_CONTEXT_MAJOR_VERSION, -1,
michael@0:             SK_WGL_CONTEXT_MINOR_VERSION, -1,
michael@0:             SK_WGL_CONTEXT_PROFILE_MASK,  SK_WGL_CONTEXT_CORE_PROFILE_BIT,
michael@0:             0,
michael@0:         };
michael@0:         for (int v = 0; v < SK_ARRAY_COUNT(kCoreGLVersions) / 2; ++v) {
michael@0:             coreProfileAttribs[1] = kCoreGLVersions[2 * v];
michael@0:             coreProfileAttribs[3] = kCoreGLVersions[2 * v + 1];
michael@0:             glrc = extensions.createContextAttribs(dc, NULL, coreProfileAttribs);
michael@0:             if (NULL != glrc) {
michael@0:                 break;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (NULL == glrc) {
michael@0:         glrc = wglCreateContext(dc);
michael@0:     }
michael@0:     SkASSERT(glrc);
michael@0: 
michael@0:     wglMakeCurrent(prevDC, prevGLRC);
michael@0:     return glrc;
michael@0: }