Input and Interaction课件.pptVIP

Display List in OpenGL Matrix computation Image display Light, material Texture Polygonal objects display Display List in OpenGL void glNewList(GLuint list, GLenum mode); mode: GL_COMPILE and GL_COMPILE_AND_EXECUTE void glEndList(void); NOT included in Display List: glDeleteLists() glIsEnable() glFeedbackBuffer() glIsList() glFinish() glPixelStore() glGenLists() glRenderMode() glGet*() glSelectBuffer() Display List in OpenGL Example: GLuint listName = 1; void myinit (void) { glNewList (listName, GL_COMPILE); glColor3f (1.0, 0.0, 0.0); glBegin (GL_TRIANGLES); glVertex2f (0.0, 0.0); glVertex2f (1.0, 0.0); glVertex2f (0.0, 1.0); glEnd (); glTranslatef (1.5, 0.0, 0.0); glEndList (); glShadeModel (GL_FLAT); } void CALLBACK display(void) { GLuint i; glClear(GL_COLOR_BUFFER_BIT); glColor3f (0.0, 1.0, 0.0); glPushMatrix(); for (i = 0; i 5; i++) glCallList (listName); drawLine (); glPopMatrix(); glFlush (); } ? Input Mode Input devices contain a trigger which can be used to send a signal to the operating system Button on mouse Pressing or releasing a key When triggered, input devices return information (their measure) to the system Mouse returns position information Keyboard returns ASCII code Request Mode Input provided to program only when user triggers the device Typical of keyboard input Can erase (backspace), edit, correct until enter (return) key (the trigger) is depressed 1. Program requests measure of a device and blocks. 2. Measure process maintains current measure. 3. Trigger process signals measure process to return measure. request_locator(device_id, measure); Event Mode Most systems have more than one input device, each of which can be triggered at an arbitrary time by a user Each trigger generates an event whose measure is put in an event queue which can be examined by the user program glutMainLoop(); Event Types Window: resize, expose, iconify Mouse: click one or more buttons Motion: mo