// This Program introduces the ability to draw multiple sub windows. // It uses the command glOrtho() for orthographic projection and scaling. // as well as keyboard and mouse routines. #include #include #include #include // Integers to identify the three windows int main_window, sub_window1, sub_window2; // These are evil global variables that determine the main window size int width=830; // Two 400 pixel windows and three 10-pixel borders int height=420; // Top and bottom borders of 10 pixels each. // This string will be used to display which window is being viewed. char s[10] ="Window n"; // These values will be used to zoom in and out of the second window. // Initial values for the zoom are the same as the fixed window. float orthoX1= 1.0, orthoY1=1.0; // This is a function that will do something when a key is pressed in Window 1 void key_pressed1(unsigned char key, int x, int y) { if (isprint(key)) { printf("First Subwindow key: `%c' %d,%d\n", key, x, y); } else { printf("First Subwindow key: 0x%x %d,%d\n", key, x, y); } } // This is a function that will do something when a key is pressed in Window 2 void key_pressed2(unsigned char key, int x, int y) { if (isprint(key)) { printf("Second Subwindow key: `%c' %d,%d\n", key, x, y); } else { printf("Second Subwindow key: 0x%x %d,%d\n", key, x, y); } } // This routine tells what to do when the mouse is used in Window 1 // It will zoom into Window 2 making the image larger. void mouse1(int button, int state, int x, int y) { printf("WINDOW 1: button: %d %s %d,%d\n", button, state == GLUT_UP ? "UP" : "down", x, y); if (state == GLUT_DOWN){ orthoX1 -= 0.2; orthoY1 -= 0.2; glutSetWindow(sub_window2); // Reset Window #2 glutPositionWindow( (width-30)/2+20,10); // Figure out top corner glutReshapeWindow( (width-30)/2, height-20); // Figure out size } glutPostRedisplay(); // Cause the image to be redisplayed } // This routine tells what to do when the mouse is used in Window 2 // It will zoom out of Window 2 making the image smaller. void mouse2(int button, int state, int x, int y) { printf("WINDOW 2: button: %d %s %d,%d\n", button, state == GLUT_UP ? "UP" : "down", x, y); if (state == GLUT_DOWN){ orthoX1 += 0.2; orthoY1 += 0.2; glutSetWindow(sub_window2); // Reset Window #2 glutPositionWindow( (width-30)/2+20,10); // Figure out top corner glutReshapeWindow( (width-30)/2, height-20); // Figure out size } glutPostRedisplay(); // Force redisplay } // The following code permits drawing text on the screen // Bitmap character fonts must be pre-defined void bitmap_output(int x, int y, int z, char *string, void *font) { int len, i; glRasterPos3f(x, y, 0); len = (int) strlen(string); for (i = 0; i < len; i++) { glutBitmapCharacter(font, string[i]); } } // Draws a graph of a simple line. DrawGraph() { float x; glBegin(GL_POINTS); // Start drawing points glColor3f(0.0,0.0,0.0); // Set drawing color to black for (x=-0.9; x<0.9; x+=0.01) // Step through x values {glVertex3f(x,x,0.0); // Put a point at (x,x) } glEnd(); } // Draws a set of labeled axes DrawAxes() { glBegin(GL_LINES); glColor3f(1.0, 1.0, 0.0); glVertex3f(-0.9,0.0, 0.0); // Draw x-axis glVertex3f(0.9, 0.0, 0.0); glVertex3f(0.0, -0.9,0.0); // Draw y-axis glVertex3f(0.0, 0.9, 0.0); glEnd(); glPushMatrix(); // Label y-axis glTranslatef(0.05, 0.85, 0); bitmap_output(0,0,0, "y", GLUT_BITMAP_TIMES_ROMAN_24); glPopMatrix(); glPushMatrix(); // Label x-axis glTranslatef(0.8, -0.1, 0); bitmap_output(0,0,0, "x", GLUT_BITMAP_TIMES_ROMAN_24); glPopMatrix(); } //Draws some titles on the screen in available Times Roman fonts void DrawTitles( ) { glColor3f(0.0, 0.0, 0.0); glPushMatrix(); glTranslatef(-0.9, 0.8, 0); bitmap_output(0,0,0, s, GLUT_BITMAP_TIMES_ROMAN_24); glPopMatrix(); glPushMatrix(); glTranslatef(-0.5, -0.95, 0); bitmap_output(0,0,0, "The above graph is for the linear equation y = x", GLUT_BITMAP_TIMES_ROMAN_10); glPopMatrix(); } // Left Display Window is RED. void display1(void) { glClearColor(1.0, 0.0, 0.0, 1.0); glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 ); // Default scaling (-1..+1) sprintf(s,"Window 1"); DrawAxes(); DrawGraph(); DrawTitles(); glFlush(); // Force writing of GL commands } // Right Display Window is BLUE. void display2(void) { glClearColor(0.0, 0.0, 1.0, 1.0); glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glOrtho( -orthoX1, orthoX1, -orthoY1, orthoY1, -1.0, 1.0 ); sprintf(s,"Window 2"); DrawAxes(); DrawGraph(); DrawTitles(); glFlush(); // Force writing of GL commands } // Main display is WHITE. void display(void) { glClearColor(1.0, 1.0, 1.0, 1.0); glClear(GL_COLOR_BUFFER_BIT); } // This routine tells what to do if the window is resized. void reshape(int w, int h) { glViewport(0, 0, w, h); // This gets coordinates of the new window width = w; height = h; glutSetWindow(sub_window1); // Stuff for window #1 glutPositionWindow(10,10); glutReshapeWindow( (width-30)/2, height-20); glutSetWindow(sub_window2); // Stuff for window #2 glutPositionWindow( (width-30)/2 + 20 ,10); glutReshapeWindow( (width-30)/2, height-20); } int main(int argc, char **argv) { // Initialization stuff glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGB); glutInitWindowSize(width, height); // Make Main outer window main_window = glutCreateWindow("Two Active Windows "); glutDisplayFunc(display); glutReshapeFunc(reshape); // Create First subwindow sub_window1 = glutCreateSubWindow(main_window, 10, 10, 400 , 400); glutDisplayFunc(display1); // Pointer to display function glutKeyboardFunc(key_pressed1); // Pointer to keyboard function glutMouseFunc(mouse1); // Pointer to mouse routine // Create second subwindow sub_window2 = glutCreateSubWindow(main_window, 420, 10, 400, 400); glutDisplayFunc(display2); // Pointer do other display function glutKeyboardFunc(key_pressed2); // Pointer to other keyboard function glutMouseFunc(mouse2); // Pointer to other mouse routine // Enter Glut Main Loop and wait for events glutMainLoop(); return 0; /* ANSI C requires main to return int. */ }