text: /*************************************************************************
   *                                                                       *
   * Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith.       *
   * All rights reserved.  Email: russ@q12.org   Web: www.q12.org          *
   *                                                                       *
   * This library is free software; you can redistribute it and/or         *
   * modify it under the terms of EITHER:                                  *
   *   (1) The GNU Lesser General Public License as published by the Free  *
   *       Software Foundation; either version 2.1 of the License, or (at  *
   *       your option) any later version. The text of the GNU Lesser      *
   *       General Public License is included with this library in the     *
   *       file LICENSE.TXT.                                               *
   *   (2) The BSD-style license that is included with this library in     *
   *       the file LICENSE-BSD.TXT.                                       *
   *                                                                       *
   * This library is distributed in the hope that it will be useful,       *
   * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files    *
   * LICENSE.TXT and LICENSE-BSD.TXT for more details.                     *
   *                                                                       *
   *************************************************************************/
  
  // main window and event handling for X11
  
  #include <ode/odeconfig.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdarg.h>
  #include <X11/Xlib.h>
  #include <X11/Xatom.h>
  #include <X11/keysym.h>
  #include <GL/glx.h>
  #include "config.h"
  #include "common.h"
  
  #ifdef HAVE_SYS_TIME_H
  #include <sys/time.h>
  #endif
  #ifdef HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  
  #include <drawstuff/drawstuff.h>
  #include <drawstuff/version.h>
  #include "internal.h"
  
  //***************************************************************************
  // error handling for unix
  
  static void printMessage (const char *msg1, const char *msg2, va_list ap)
  {
    fflush (stderr);
    fflush (stdout);
    fprintf (stderr,"\n%s: ",msg1);
    vfprintf (stderr,msg2,ap);
    fprintf (stderr,"\n");
    fflush (stderr);
  }
  
  
  extern "C" void dsError (const char *msg, ...)
  {
    va_list ap;
    va_start (ap,msg);
    printMessage ("Error",msg,ap);
    va_end (ap);
    exit (1);
  }
  
  
  extern "C" void dsDebug (const char *msg, ...)
  {
    va_list ap;
    va_start (ap,msg);
    printMessage ("INTERNAL ERROR",msg,ap);
    va_end (ap);
    // *((char *)0) = 0;	 ... commit SEGVicide ?
    abort();
  }
  
  
  extern "C" void dsPrint (const char *msg, ...)
  {
    va_list ap;
    va_start (ap,msg);
    vprintf (msg,ap);
    va_end (ap);
  }
  
  //***************************************************************************
  // openGL window
  
  // X11 display info
  static Display *display=0;
  static int screen=0;
  static XVisualInfo *visual=0;		// best visual for openGL
  static Colormap colormap=0;		// window's colormap
  static Atom wm_protocols_atom = 0;
  static Atom wm_delete_window_atom = 0;
  
  // window and openGL
  static Window win=0;			// X11 window, 0 if not initialized
  static int width=0,height=0;		// window size
  static GLXContext glx_context=0;	// openGL rendering context
  static int last_key_pressed=0;		// last key pressed in the window
  static int run=1;			// 1 if simulation running
  static int pausemode=0;			// 1 if in `pause' mode
  static int singlestep=0;		// 1 if single step key pressed
  static int writeframes=0;		// 1 if frame files to be written
  
  
  static void createMainWindow (int _width, int _height)
  {
    // create X11 display connection
    display = XOpenDisplay (NULL);
    if (!display) dsError ("can not open X11 display");
    screen = DefaultScreen(display);
  
    // get GL visual
    static int attribListDblBuf[] = {GLX_RGBA, GLX_DOUBLEBUFFER, GLX_DEPTH_SIZE,16,
  			     GLX_RED_SIZE,4, GLX_GREEN_SIZE,4, GLX_BLUE_SIZE,4, None};
    static int attribList[] = {GLX_RGBA, GLX_DEPTH_SIZE,16,
  			     GLX_RED_SIZE,4, GLX_GREEN_SIZE,4, GLX_BLUE_SIZE,4, None};
    visual = glXChooseVisual (display,screen,attribListDblBuf);
    if (!visual) visual = glXChooseVisual (display,screen,attribList);
    if (!visual) dsError ("no good X11 visual found for OpenGL");
  
    // create colormap
    colormap = XCreateColormap (display,RootWindow(display,screen),
  			      visual->visual,AllocNone);
  
    // initialize variables
    win = 0;
    width = _width;
    height = _height;
    glx_context = 0;
    last_key_pressed = 0;
  
    if (width < 1 || height < 1) dsDebug (0,"bad window width or height");
  
    // create the window
    XSetWindowAttributes attributes;
    attributes.background_pixel = BlackPixel(display,screen);
    attributes.colormap = colormap;
    attributes.event_mask = ButtonPressMask | ButtonReleaseMask |
      KeyPressMask | KeyReleaseMask | ButtonMotionMask | PointerMotionHintMask |
      StructureNotifyMask;
    win = XCreateWindow (display,RootWindow(display,screen),50,50,width,height,
  		       0,visual->depth, InputOutput,visual->visual,
  		       CWBackPixel | CWColormap | CWEventMask,&attributes);
  
    // associate a GLX context with the window
    glx_context = glXCreateContext (display,visual,0,GL_TRUE);
    if (!glx_context) dsError ("can't make an OpenGL context");
  
    // set the window title
    XTextProperty window_name;
    window_name.value = (unsigned char *) "Simulation";
    window_name.encoding = XA_STRING;
    window_name.format = 8;
    window_name.nitems = strlen((char *) window_name.value);
    XSetWMName (display,win,&window_name);
  
    // participate in the window manager 'delete yourself' protocol
    wm_protocols_atom = XInternAtom (display,"WM_PROTOCOLS",False);
    wm_delete_window_atom = XInternAtom (display,"WM_DELETE_WINDOW",False);
    if (XSetWMProtocols (display,win,&wm_delete_window_atom,1)==0)
      dsError ("XSetWMProtocols() call failed");
  
    // pop up the window
    XMapWindow (display,win);
    XSync (display,win);
  }
  
  
  static void destroyMainWindow()
  {
    glXDestroyContext (display,glx_context);
    XDestroyWindow (display,win);
    XSync (display,0);
    XCloseDisplay(display);
    display = 0;
    win = 0;
    glx_context = 0;
  }
  
  
  static void handleEvent (XEvent &event, dsFunctions *fn)
  {
    static int mx=0,my=0; 	// mouse position
    static int mode = 0;		// mouse button bits
  
    switch (event.type) {
  
    case ButtonPress: {
      if (event.xbutton.button == Button1) mode |= 1;
      if (event.xbutton.button == Button2) mode |= 2;
      if (event.xbutton.button == Button3) mode |= 4;
      mx = event.xbutton.x;
      my = event.xbutton.y;
    }
    return;
  
    case ButtonRelease: {
      if (event.xbutton.button == Button1) mode &= (~1);
      if (event.xbutton.button == Button2) mode &= (~2);
      if (event.xbutton.button == Button3) mode &= (~4);
      mx = event.xbutton.x;
      my = event.xbutton.x;
    }
    return;
  
    case MotionNotify: {
      if (event.xmotion.is_hint) {
        Window root,child;
        unsigned int mask;
        XQueryPointer (display,win,&root,&child,&event.xbutton.x_root,
  		     &event.xbutton.y_root,&event.xbutton.x,&event.xbutton.y,
  		     &mask);
      }
      dsMotion (mode, event.xmotion.x - mx, event.xmotion.y - my);
      mx = event.xmotion.x;
      my = event.xmotion.y;
    }
    return;
  
    case KeyPress: {
      KeySym key;
      XLookupString (&event.xkey,NULL,0,&key,0);
      if ((event.xkey.state & ControlMask) == 0) {
        if (key >= ' ' && key <= 126 && fn->command) fn->command (key);
      }
      else if (event.xkey.state & ControlMask) {
        switch (key) {
        case 't': case 'T':
  	dsSetTextures (dsGetTextures() ^ 1);
  	break;
        case 's': case 'S':
  	dsSetShadows (dsGetShadows() ^ 1);
  	break;
        case 'x': case 'X':
  	run = 0;
  	break;
        case 'p': case 'P':
  	pausemode ^= 1;
  	singlestep = 0;
  	break;
        case 'o': case 'O':
  	if (pausemode) singlestep = 1;
  	break;
        case 'v': case 'V': {
  	float xyz[3],hpr[3];
  	dsGetViewpoint (xyz,hpr);
  	printf ("Viewpoint = (%.4f,%.4f,%.4f,%.4f,%.4f,%.4f)\n",
  		xyz[0],xyz[1],xyz[2],hpr[0],hpr[1],hpr[2]);
  	break;
        }
        case 'w': case 'W':
  	writeframes ^= 1;
  	if (writeframes) printf ("Now writing frames to PPM files\n");
  	break;
        }
      }
      last_key_pressed = key;		// a kludgy place to put this...
    }
    return;
  
    case KeyRelease: {
      // hmmmm...
    }
    return;
  
    case ClientMessage:
      if (event.xclient.message_type == wm_protocols_atom &&
  	event.xclient.format == 32 &&
  	Atom(event.xclient.data.l[0]) == wm_delete_window_atom) {
        run = 0;
        return;
      }
      return;
  
    case ConfigureNotify:
      width = event.xconfigure.width;
      height = event.xconfigure.height;
      return;
    }
  }
  
  
  // return the index of the highest bit
  static int getHighBitIndex (unsigned int x)
  {
    int i = 0;
    while (x) {
      i++;
      x >>= 1;
    }
    return i-1;
  }
  
  
  // shift x left by i, where i can be positive or negative
  #define SHIFTL(x,i) (((i) >= 0) ? ((x) << (i)) : ((x) >> (-i)))
  
  
  static void captureFrame (int num)
  {
    fprintf (stderr,"capturing frame %04d\n",num);
  
    char s[100];
    sprintf (s,"frame/frame%04d.ppm",num);
    FILE *f = fopen (s,"wb");
    if (!f) dsError ("can't open \"%s\" for writing",s);
    fprintf (f,"P6\n%d %d\n255\n",width,height);
    XImage *image = XGetImage (display,win,0,0,width,height,~0,ZPixmap);
  
    int rshift = 7 - getHighBitIndex (image->red_mask);
    int gshift = 7 - getHighBitIndex (image->green_mask);
    int bshift = 7 - getHighBitIndex (image->blue_mask);
  
    for (int y=0; y<height; y++) {
      for (int x=0; x<width; x++) {
        unsigned long pixel = XGetPixel (image,x,y);
        unsigned char b[3];
        b[0] = SHIFTL(pixel & image->red_mask,rshift);
        b[1] = SHIFTL(pixel & image->green_mask,gshift);
        b[2] = SHIFTL(pixel & image->blue_mask,bshift);
        fwrite (b,3,1,f);
      }
    }
    fclose (f);
    XDestroyImage (image);
  }
  
  void processDrawFrame(int *frame, dsFunctions *fn)
  {
    dsDrawFrame (width,height,fn,pausemode && !singlestep);
    singlestep = 0;
  
    glFlush();
    glXSwapBuffers (display,win);
    XSync (display,0);
  
    // capture frames if necessary
    if (pausemode==0 && writeframes) {
      captureFrame (*frame);
      (*frame)++;
    }
  }
  
  void microsleep(int usecs)
  {
  #ifdef HAVE_UNISTD_H
    usleep(usecs);
  #endif
  }
  
  void dsPlatformSimLoop (int window_width, int window_height, dsFunctions *fn,
  			int initial_pause)
  {
    pausemode = initial_pause;
    createMainWindow (window_width, window_height);
    glXMakeCurrent (display,win,glx_context);
  
    dsStartGraphics (window_width,window_height,fn);
  
    static bool firsttime=true;
    if (firsttime)
    {
      fprintf
      (
        stderr,
        "\n"
        "Simulation test environment v%d.%02d\n"
        "   Ctrl-P : pause / unpause (or say `-pause' on command line).\n"
        "   Ctrl-O : single step when paused.\n"
        "   Ctrl-T : toggle textures (or say `-notex' on command line).\n"
        "   Ctrl-S : toggle shadows (or say `-noshadow' on command line).\n"
        "   Ctrl-V : print current viewpoint coordinates (x,y,z,h,p,r).\n"
        "   Ctrl-W : write frames to ppm files: frame/frameNNN.ppm\n"
        "   Ctrl-X : exit.\n"
        "\n"
        "Change the camera position by clicking + dragging in the window.\n"
        "   Left button - pan and tilt.\n"
        "   Right button - forward and sideways.\n"
        "   Left + Right button (or middle button) - sideways and up.\n"
        "\n",DS_VERSION >> 8,DS_VERSION & 0xff
      );
      firsttime = false;
    }
  
    if (fn->start) fn->start();
  
  #if HAVE_GETTIMEOFDAY
    timeval tv;
    gettimeofday(&tv, 0);
    double prev = tv.tv_sec + (double) tv.tv_usec / 1000000.0 ;
  #endif
  
    int frame = 1;
    run = 1;
    while (run) {
      // read in and process all pending events for the main window
      XEvent event;
      while (run && XPending (display)) {
        XNextEvent (display,&event);
        handleEvent (event,fn);
      }
      
  #if HAVE_GETTIMEOFDAY
      gettimeofday(&tv, 0);
      double curr = tv.tv_sec + (double) tv.tv_usec / 1000000.0 ;
      if (curr-prev >= 1.0/60.0)
      {
        prev = curr;
        processDrawFrame(&frame, fn);
      }
      else
        microsleep(1000);
  #else
      processDrawFrame(&frame, fn);
  #endif
    };
  
    if (fn->stop) fn->stop();
    dsStopGraphics();
  
    destroyMainWindow();
  }
  
  
  extern "C" void dsStop()
  {
    run = 0;
  }
  
  
  extern "C" double dsElapsedTime()
  {
  #if HAVE_GETTIMEOFDAY
    static double prev=0.0;
    timeval tv ;
  
    gettimeofday(&tv, 0);
    double curr = tv.tv_sec + (double) tv.tv_usec / 1000000.0 ;
    if (!prev)
      prev=curr;
    double retval = curr-prev;
    prev=curr;
    if (retval>1.0) retval=1.0;
    if (retval<dEpsilon) retval=dEpsilon;
    return retval;
  #else
    return 0.01666; // Assume 60 fps
  #endif
  }
  
  
  
  