opengl_wrapper_win.cpp

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#include "wglew.h"
 
#include <cassert>
 
#ifndef UNICODE
#define UNICODE
#endif
#define NOMINMAX
#define WIN32_LEAN_AND_MEAN
 
#include "Windows.h"
 
namespace ogl {
 
void create_opengl_context(sys::state& state) {
    assert(state.win_ptr && state.win_ptr->hwnd && !state.open_gl.context);
 
    HDC window_dc = state.win_ptr->opengl_window_dc;
 
    PIXELFORMATDESCRIPTOR pfd;
    ZeroMemory(&pfd, sizeof(pfd));
    pfd.nSize = sizeof(pfd);
    pfd.nVersion = 1;
    pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
    pfd.iPixelType = PFD_TYPE_RGBA;
    pfd.cColorBits = 32;
    pfd.cDepthBits = 24;
    pfd.cStencilBits = 8;
    pfd.iLayerType = PFD_MAIN_PLANE;
    int const pixel_format = ChoosePixelFormat(window_dc, &pfd);
    SetPixelFormat(window_dc, pixel_format, &pfd);
 
    auto handle_to_ogl_dc = wglCreateContext(window_dc);
    wglMakeCurrent(window_dc, handle_to_ogl_dc);
 
    if(glewInit() != 0) {
        window::emit_error_message("GLEW failed to initialize", true);
    }
 
    if(!wglewIsSupported("WGL_ARB_create_context")) {
        window::emit_error_message("WGL_ARB_create_context not supported", true);
    }
 
    // Explicitly request for OpenGL 3.1
    static const int attribs_3_1[] = {
        WGL_CONTEXT_MAJOR_VERSION_ARB, 3,
        WGL_CONTEXT_MINOR_VERSION_ARB, 1,
        WGL_CONTEXT_FLAGS_ARB,
#ifndef NDEBUG
        WGL_CONTEXT_DEBUG_BIT_ARB |
#endif
        0,
        WGL_CONTEXT_PROFILE_MASK_ARB,
        WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
        0
    };
    state.open_gl.context = wglCreateContextAttribsARB(window_dc, nullptr, attribs_3_1);
    if(state.open_gl.context == nullptr) {
        window::emit_error_message("Unable to create WGL context", true);
    }
 
    wglMakeCurrent(window_dc, HGLRC(state.open_gl.context));
    wglDeleteContext(handle_to_ogl_dc);
 
    // wglMakeCurrent(window_dc, HGLRC(state.open_gl.context));
#ifndef NDEBUG
    glDebugMessageCallback(debug_callback, nullptr);
    glDebugMessageControl(GL_DONT_CARE, GL_DONT_CARE, GL_DONT_CARE, 0, nullptr, GL_TRUE);
    glDebugMessageControl(GL_DONT_CARE, GL_DEBUG_TYPE_OTHER, GL_DEBUG_SEVERITY_LOW, 0, nullptr, GL_FALSE);
#endif
 
    if(wglewIsSupported("WGL_EXT_swap_control_tear") == 1) {
        wglSwapIntervalEXT(-1);
    } else if(wglewIsSupported("WGL_EXT_swap_control") == 1) {
        wglSwapIntervalEXT(1);
    } else {
        MessageBoxW(state.win_ptr->hwnd, L"WGL_EXT_swap_control_tear and WGL_EXT_swap_control not supported", L"OpenGL error", MB_OK);
    }
}
 
void shutdown_opengl(sys::state& state) {
    assert(state.win_ptr && state.win_ptr->hwnd && state.open_gl.context);
    wglMakeCurrent(state.win_ptr->opengl_window_dc, nullptr);
    wglDeleteContext(HGLRC(state.open_gl.context));
    state.open_gl.context = nullptr;
}
} // namespace ogl