Managing Multiple Windows with OpenGL and GLUT.ppt

* * * Managing Multiple WindowswithOpenGL and GLUT A mini-tutorial Based upon: The OpenGL Utility Toolkit (GLUT) Programming Interface API Version 3 Mark J. Kilgard Copyright 1996 Two (or more) OpenGL/GLUT Windows Callbacks Display Func. Mouse Func. Reshape Func. Keyboard Func. Etc. Callbacks Display Func. Mouse Func. Reshape Func. Keyboard Func. Etc. OpenGL State OpenGL State Frame Buffer Idle Function Shared Window 1 Window 2 Steps for Creating Multiple Windows Initialize drawing context and frame buffer using glutInit(), glutInitDisplayMode(), and glutInitWindowSize(). Create first window Register callbacks for first window Create second window Position the second window Register callbacks for second window Register (shared) idle callback Enter the main loop Note: Callbacks can be shared between windows, if desired Creating a Window int glutCreateWindow(char *name); Unique identifier of the window created Name of the window Appears at top in window decoration Creates a window data structure and returns a small integer identifier. Window is not displayed until the main loop is entered Window becomes the current window. The current window Can be set or obtained using glutSetWindow() and glutGetWindow(). Behavior of Callback Functions Keyboard and mouse events are routed by the event loop to the callbacks registered for the current active window. Display events are generated for each window separately when the O/S determines that the window must be redisplayed. Display events can be user generated using glutPostRedisplay(). These events are routed to the display callback for the current window. The shared idle() function is executed whenever no events are present in the event queue. Example Using Two Windows glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB |GLUT_DEPTH); glutInitWindowSize(500, 500); // create the first window window1 = glutCreateWindow(First Window - Perspective View); // register callbacks for first window, which is now curren