SwapBuffers(hDC);

/**
    Também está cheia de ídolos a sua terra; inclinaram-se perante a
    obra das suas mãos, diante daquilo que fabricaram os seus dedos.
    Isaías 2:8
*/

#include <windows.h>
#include <gl/gl.h>
#include "resource.h"

LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM);
void EnableOpenGL(HWND hwnd, HDC*, HGLRC*);
void DisableOpenGL(HWND, HDC, HGLRC);


int WINAPI WinMain(HINSTANCE hI, HINSTANCE hPI, LPSTR lpCmdLine, int iCS) {
    WNDCLASSEX wcex;
    HWND       hwnd;
    HDC        hDC;
    HGLRC      hRC;
    MSG        msg;
    BOOL  bQuit = FALSE;
    float theta = 0.0f;

    /* register window class */
    wcex.cbSize        = sizeof(WNDCLASSEX);
    wcex.style         = CS_OWNDC;
    wcex.lpfnWndProc   = WindowProc;
    wcex.cbClsExtra    = 0;
    wcex.cbWndExtra    = 0;
    wcex.hInstance     = hI;
    wcex.hIcon         = LoadIcon(hI, IDI_ICON);
    wcex.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
    wcex.lpszMenuName  = NULL;
    wcex.lpszClassName = "GLSample";
    wcex.hIconSm       = LoadIcon(NULL, IDI_ICON);


    if (!RegisterClassEx(&wcex))
        return 0;

    /* create main window */
    hwnd = CreateWindowEx(
        0, "GLSample", "SwapBuffers", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 360, 256,
        NULL, NULL, hI, NULL
    );

    ShowWindow(hwnd, iCS);

    EnableOpenGL(hwnd, &hDC, &hRC);

    while(!bQuit) {
        if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
            if(msg.message == WM_QUIT) {
                bQuit = TRUE;
            }
            else {
                TranslateMessage(&msg);
                DispatchMessage(&msg);
                FreeConsole();
            }
        }
        else {
            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
            glClear(GL_COLOR_BUFFER_BIT);

            glPushMatrix();
            glRotatef(theta, 0.0f, 0.0f, 1.0f);

            glBegin(GL_TRIANGLES);

            glColor3f(1.0f, 1.0f, 1.0f);   glVertex2f(0.0f,   1.0f);
            glColor3f(0.0f, 1.0f, 0.9f);   glVertex2f(0.87f,  -0.5f);
            glColor3f(0.0f, 0.0f, 1.0f);   glVertex2f(-0.87f, -0.5f);

            glEnd();

            glPopMatrix();

            SwapBuffers(hDC);

            theta += 1.0f;
            Sleep(1);
        }
    }

    DisableOpenGL(hwnd, hDC, hRC);

    DestroyWindow(hwnd);

    return msg.wParam;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg, WPARAM wP, LPARAM lParam) {
    switch(msg) {
        case WM_CLOSE:
            PostQuitMessage(0);
        break;

        case WM_DESTROY:
            return 0;

        case WM_KEYDOWN:
        {
            switch(wP) {
                case VK_ESCAPE:
                    PostQuitMessage(0);
                break;
            }
        }
        break;

        default:
            return DefWindowProc(hwnd, msg, wP, lParam);
    }

    return 0;
}

void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC) {
    PIXELFORMATDESCRIPTOR pfd;

    int iFormat;

    *hDC = GetDC(hwnd);

    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 = 24;
    pfd.cDepthBits = 16;
    pfd.iLayerType = PFD_MAIN_PLANE;

    iFormat = ChoosePixelFormat(*hDC, &pfd);

    SetPixelFormat(*hDC, iFormat, &pfd);

    *hRC = wglCreateContext(*hDC);

    wglMakeCurrent(*hDC, *hRC);
}

void DisableOpenGL(HWND hwnd, HDC hDC, HGLRC hRC) {
    wglMakeCurrent(NULL, NULL);
    wglDeleteContext(hRC);
    ReleaseDC(hwnd, hDC);
}

/********** resource.h **********/

#define IDI_ICON 1

/********** resource.rc **********/

#include "resource.h"

IDI_ICON ICON "icone.ico"