ui/gl/gl_context_wgl.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file implements the GLContextWGL and PbufferGLContext classes.
   6
   7 #include "ui/gl/gl_context_wgl.h"
   8
   9 #include "base/debug/trace_event.h"
  10 #include "base/logging.h"
  11 #include "ui/gl/gl_bindings.h"
  12 #include "ui/gl/gl_implementation.h"
  13 #include "ui/gl/gl_surface_wgl.h"
  14
  15 namespace gfx {
  16
  17 GLContextWGL::GLContextWGL(GLShareGroup* share_group)
  18     : GLContextReal(share_group),
  19       context_(NULL) {
  20 }
  21
  22 GLContextWGL::~GLContextWGL() {
  23   Destroy();
  24 }
  25
  26 std::string GLContextWGL::GetExtensions() {
  27   const char* extensions = NULL;
  28   if (g_driver_wgl.fn.wglGetExtensionsStringARBFn)
  29     extensions = wglGetExtensionsStringARB(GLSurfaceWGL::GetDisplayDC());
  30   else if (g_driver_wgl.fn.wglGetExtensionsStringEXTFn)
  31     extensions = wglGetExtensionsStringEXT();
  32
  33   if (extensions)
  34     return GLContext::GetExtensions() + " " + extensions;
  35
  36   return GLContext::GetExtensions();
  37 }
  38
  39 bool GLContextWGL::Initialize(
  40     GLSurface* compatible_surface, GpuPreference gpu_preference) {
  41   // Get the handle of another initialized context in the share group _before_
  42   // setting context_. Otherwise this context will be considered initialized
  43   // and could potentially be returned by GetHandle.
  44   HGLRC share_handle = static_cast<HGLRC>(share_group()->GetHandle());
  45
  46   context_ = wglCreateContext(
  47       static_cast<HDC>(compatible_surface->GetHandle()));
  48   if (!context_) {
  49     LOG(ERROR) << "Failed to create GL context.";
  50     Destroy();
  51     return false;
  52   }
  53
  54   if (share_handle) {
  55     if (!wglShareLists(share_handle, context_)) {
  56       LOG(ERROR) << "Could not share GL contexts.";
  57       Destroy();
  58       return false;
  59     }
  60   }
  61
  62   return true;
  63 }
  64
  65 void GLContextWGL::Destroy() {
  66   if (context_) {
  67     wglDeleteContext(context_);
  68     context_ = NULL;
  69   }
  70 }
  71
  72 bool GLContextWGL::MakeCurrent(GLSurface* surface) {
  73   DCHECK(context_);
  74   if (IsCurrent(surface))
  75     return true;
  76
  77   TRACE_EVENT0("gpu", "GLContextWGL::MakeCurrent");
  78
  79   if (!wglMakeCurrent(static_cast<HDC>(surface->GetHandle()), context_)) {
  80     LOG(ERROR) << "Unable to make gl context current.";
  81     return false;
  82   }
  83
  84   // Set this as soon as the context is current, since we might call into GL.
  85   SetRealGLApi();
  86
  87   SetCurrent(surface);
  88   if (!InitializeExtensionBindings()) {
  89     ReleaseCurrent(surface);
  90     return false;
  91   }
  92
  93   if (!surface->OnMakeCurrent(this)) {
  94     LOG(ERROR) << "Could not make current.";
  95     return false;
  96   }
  97
  98   return true;
  99 }
 100
 101 void GLContextWGL::ReleaseCurrent(GLSurface* surface) {
 102   if (!IsCurrent(surface))
 103     return;
 104
 105   SetCurrent(NULL);
 106   wglMakeCurrent(NULL, NULL);
 107 }
 108
 109 bool GLContextWGL::IsCurrent(GLSurface* surface) {
 110   bool native_context_is_current =
 111       wglGetCurrentContext() == context_;
 112
 113   // If our context is current then our notion of which GLContext is
 114   // current must be correct. On the other hand, third-party code
 115   // using OpenGL might change the current context.
 116   DCHECK(!native_context_is_current || (GetRealCurrent() == this));
 117
 118   if (!native_context_is_current)
 119     return false;
 120
 121   if (surface) {
 122     if (wglGetCurrentDC() != surface->GetHandle())
 123       return false;
 124   }
 125
 126   return true;
 127 }
 128
 129 void* GLContextWGL::GetHandle() {
 130   return context_;
 131 }
 132
 133 void GLContextWGL::SetSwapInterval(int interval) {
 134   DCHECK(IsCurrent(NULL));
 135   if (gfx::g_driver_wgl.ext.b_WGL_EXT_swap_control) {
 136     wglSwapIntervalEXT(interval);
 137   } else {
 138       LOG(WARNING) <<
 139           "Could not disable vsync: driver does not "
 140           "support WGL_EXT_swap_control";
 141   }
 142 }
 143
 144 }  // namespace gfx