main.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <GL/gl.h>
#include <GL/glx.h>
#include <GL/glu.h>
struct Hints {
    unsigned long flags;
    unsigned long functions;
    unsigned long decorations;
    long inputMode;
    unsigned long status;
};
Display *display;
Window rootWindow, window;
Colormap colormap;
XVisualInfo *visualInfo;
XSetWindowAttributes setWindowAttributes;
int screenWidth, screenHeight, scissorOffsetX, scissorOffsetY;
GLint attributes[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
Atom property;
struct Hints hints;
GLXContext context;
XWindowAttributes windowAttributes;
int x11FileDescriptor;
fd_set inputFileDescriptorSet;
struct timeval timer;
int test = 0;
void SetupWindow()
{
    display = XOpenDisplay(NULL);
    rootWindow = DefaultRootWindow(display);
    visualInfo = glXChooseVisual(display, 0, attributes);
    colormap = XCreateColormap(display, rootWindow, visualInfo->visual, AllocNone);
    setWindowAttributes.colormap = colormap;
    setWindowAttributes.event_mask = ExposureMask | KeyPressMask;
    screenWidth = XDisplayWidth(display, 0);
    screenHeight = XDisplayHeight(display, 0);
    window = XCreateWindow(display, rootWindow, 0, 0, screenWidth, screenHeight, 0, visualInfo->depth, InputOutput, visualInfo->visual, CWColormap | CWEventMask, &setWindowAttributes);
    hints.flags = 2;
    hints.decorations = 0;
    property = XInternAtom(display, "_MOTIF_WM_HINTS", 1);
    XChangeProperty(display, window, property, property, 32, PropModeReplace, (unsigned char *)&hints, 5);
    XSelectInput(display, window, ExposureMask | KeyPressMask | KeyReleaseMask | PointerMotionMask |
                    ButtonPressMask | ButtonReleaseMask  | StructureNotifyMask | ClientMessage );
    XMapWindow(display, window);
    XStoreName(display, window, "Hello, world!");
    XFlush(display);
    x11FileDescriptor = ConnectionNumber(display);
    context = glXCreateContext(display, visualInfo, NULL, GL_TRUE);
    glXMakeCurrent(display, window, context);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_SCISSOR_TEST);
    XGetWindowAttributes(display, window, &windowAttributes);
    //scissorOffsetX = (windowAttributes.width - 1280) / 2;
    //scissorOffsetY = (windowAttributes.height - 720) / 2;
    //glScissor(scissorOffsetX, scissorOffsetY, 1280, 720);
}
void DrawScene()
{
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glDisable(GL_SCISSOR_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glEnable(GL_SCISSOR_TEST);
    glClearColor(0.5, 0.0, 0.5, 1.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1., 1., -1., 1., 1., 20.);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(0., 0., 10., 0., 0., 0., 0., 1., 0.);

    glBegin(GL_QUADS);
    glColor3f(1.0, 0.0, 0.0); glVertex3f(-0.75, -0.75, 0.0);
    glColor3f(0.0, 1.0, 0.0); glVertex3f(0.75, -0.75, 0.0);
    glColor3f(0.0, 0.0, 1.0); glVertex3f(0.75, 0.75, 0.0);
    glColor3f(1.0, 1.0, test ? 1.0 : 0.0); glVertex3f(-.75, 0.75, 0.0);
    glEnd();
    glXSwapBuffers(display, window);
}
int main(int argc, char **argv)
{
    SetupWindow();
    XEvent event;
    int quit = 0;
    do
    {
        FD_ZERO(&inputFileDescriptorSet);
        FD_SET(x11FileDescriptor, &inputFileDescriptorSet);
        timer.tv_usec = 5000;
        timer.tv_sec = 0;
        int numReadyFDs = select(x11FileDescriptor + 1, &inputFileDescriptorSet, 0, 0, &timer);
        if (numReadyFDs > 0)
        {
            printf("Event received!\n");
        }
        else if (numReadyFDs == 0)
        {
            DrawScene();
        }
        else
        {
            printf("Error!\n");
        }
        while (XPending(display))
        {
            XNextEvent(display, &event);
            printf("event.type=%d\n",event.type);
            if (event.type == KeyPress)
            {
                KeySym key = XLookupKeysym(&event.xkey, 0);
                if (key == (KeySym)0x71) {
                    quit = 1;
                }
                else if (key == 0x61) {
                    test = 0;
                }
                else if (key == 0x62) {
                    test = 1;
                }
            }
        }
    } while (!quit);
    printf("Quitting!\n");
    XResizeWindow(display, window, 10, 10);
    XFlush(display);
    printf("Quitting2!\n");
    sleep(1);
    printf("Quitting3!\n");
    glXDestroyContext(display, context);
    XFlush(display);
    printf("Quitting4!\n");
    sleep(1);
    XCloseDisplay(display);
    printf("Quitting5!\n");
    return 0;
}