src/glut/beos/glutBlocker.cpp

   1 /***********************************************************
   2  *      Copyright (C) 1997, Be Inc.  All rights reserved.
   3  *
   4  *  FILE:       glutBlocker.cpp
   5  *
   6  *      DESCRIPTION:    helper class for GLUT event loop.
   7  *              if a window receives an event, wake up the event loop.
   8  ***********************************************************/
   9
  10 /***********************************************************
  11  *      Headers
  12  ***********************************************************/
  13 #include "glutBlocker.h"
  14
  15 /***********************************************************
  16  *      Global variable
  17  ***********************************************************/
  18 GlutBlocker gBlock;
  19
  20 /***********************************************************
  21  *      Member functions
  22  ***********************************************************/
  23 GlutBlocker::GlutBlocker() {
  24         gSem = create_sem(1, "gSem");
  25         eSem = create_sem(0, "eSem");
  26         events = false;
  27         sleeping = false;
  28 }
  29
  30 GlutBlocker::~GlutBlocker() {
  31         delete_sem(eSem);
  32         delete_sem(gSem);
  33 }
  34
  35 void GlutBlocker::WaitEvent() {
  36         acquire_sem(gSem);
  37         if(!events) {                   // wait for new event
  38                 sleeping = true;
  39                 release_sem(gSem);
  40                 acquire_sem(eSem);      // next event will release eSem
  41         } else {
  42                 release_sem(gSem);
  43         }
  44 }
  45
  46 void GlutBlocker::WaitEvent(bigtime_t usecs) {
  47         acquire_sem(gSem);
  48         if(!events) {                   // wait for new event
  49                 sleeping = true;
  50                 release_sem(gSem);
  51                 acquire_sem_etc(eSem, 1, B_TIMEOUT, usecs);     // wait for next event or timeout
  52         } else {
  53                 release_sem(gSem);
  54         }
  55 }
  56
  57 void GlutBlocker::NewEvent() {
  58         acquire_sem(gSem);
  59         events = true;          // next call to WaitEvent returns immediately
  60         if(sleeping) {
  61                 sleeping = false;
  62                 release_sem(eSem);      // if event loop is blocking, wake it up
  63         }
  64         release_sem(gSem);
  65 }