static HGLRC create_gl_context(HDC dc, SkWGLExtensions extensions, SkWGLContextRequest contextType) {
HDC prevDC = wglGetCurrentDC();
HGLRC prevGLRC = wglGetCurrentContext();
HGLRC glrc = nullptr;
if (kGLES_SkWGLContextRequest == contextType) {
if (!extensions.hasExtension(dc, "WGL_EXT_create_context_es2_profile")) {
wglMakeCurrent(prevDC, prevGLRC);
return nullptr;
}
static const int glesAttribs[] = {
SK_WGL_CONTEXT_MAJOR_VERSION, 3,
SK_WGL_CONTEXT_MINOR_VERSION, 0,
SK_WGL_CONTEXT_PROFILE_MASK, SK_WGL_CONTEXT_ES2_PROFILE_BIT,
0,
};
glrc = extensions.createContextAttribs(dc, nullptr, glesAttribs);
if (nullptr == glrc) {
wglMakeCurrent(prevDC, prevGLRC);
return nullptr;
}
} else {
if (kGLPreferCoreProfile_SkWGLContextRequest == contextType &&
extensions.hasExtension(dc, "WGL_ARB_create_context")) {
static const int kCoreGLVersions[] = {
4, 3,
4, 2,
4, 1,
4, 0,
3, 3,
3, 2,
};
int coreProfileAttribs[] = {
SK_WGL_CONTEXT_MAJOR_VERSION, -1,
SK_WGL_CONTEXT_MINOR_VERSION, -1,
SK_WGL_CONTEXT_PROFILE_MASK, SK_WGL_CONTEXT_CORE_PROFILE_BIT,
0,
};
for (int v = 0; v < SK_ARRAY_COUNT(kCoreGLVersions) / 2; ++v) {
coreProfileAttribs[1] = kCoreGLVersions[2 * v];
coreProfileAttribs[3] = kCoreGLVersions[2 * v + 1];
glrc = extensions.createContextAttribs(dc, nullptr, coreProfileAttribs);
if (glrc) {
break;
}
}
}
}
if (nullptr == glrc) {
glrc = wglCreateContext(dc);
}
SkASSERT(glrc);
wglMakeCurrent(prevDC, prevGLRC);
// This might help make the context non-vsynced.
if (extensions.hasExtension(dc, "WGL_EXT_swap_control")) {
extensions.swapInterval(-1);
}
return glrc;
}
void SkOSWindow::setVsync(bool enable) {
SkWGLExtensions wgl;
wgl.swapInterval(enable ? 1 : 0);
}