/* * 3-D gear wheels. This program is in the public domain. * * Brian Paul */ /* Conversion to GLUT by Mark J. Kilgard */ #include <math.h> #include <stdlib.h> #include <stdio.h> #include <GL/glut.h> #ifndef M_PI #define M_PI 3.14159265 #endif static GLint T0 = 0; static GLint Frames = 0; /** Draw a gear wheel. You'll probably want to call this function when building a display list since we do a lot of trig here. Input: inner_radius - radius of hole at center outer_radius - radius at center of teeth width - width of gear teeth - number of teeth tooth_depth - depth of tooth **/ static void gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width, GLint teeth, GLfloat tooth_depth) { GLint i; GLfloat r0, r1, r2; GLfloat angle, da; GLfloat u, v, len; r0 = inner_radius; r1 = outer_radius - tooth_depth / 2.0; r2 = outer_radius + tooth_depth / 2.0; da = 2.0 * M_PI / teeth / 4.0; glShadeModel(GL_FLAT); glNormal3f(0.0, 0.0, 1.0); /* draw front face */ glBegin(GL_QUAD_STRIP); for (i = 0; i <= teeth; i++) { angle = i * 2.0 * M_PI / teeth; glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); if (i < teeth) { glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); } } glEnd(); /* draw front sides of teeth */ glBegin(GL_QUADS); da = 2.0 * M_PI / teeth / 4.0; for (i = 0; i < teeth; i++) { angle = i * 2.0 * M_PI / teeth; glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5); glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5); glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); } glEnd(); glNormal3f(0.0, 0.0, -1.0); /* draw back face */ glBegin(GL_QUAD_STRIP); for (i = 0; i <= teeth; i++) { angle = i * 2.0 * M_PI / teeth; glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); if (i < teeth) { glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); } } glEnd(); /* draw back sides of teeth */ glBegin(GL_QUADS); da = 2.0 * M_PI / teeth / 4.0; for (i = 0; i < teeth; i++) { angle = i * 2.0 * M_PI / teeth; glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5); glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5); glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); } glEnd(); /* draw outward faces of teeth */ glBegin(GL_QUAD_STRIP); for (i = 0; i < teeth; i++) { angle = i * 2.0 * M_PI / teeth; glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); u = r2 * cos(angle + da) - r1 * cos(angle); v = r2 * sin(angle + da) - r1 * sin(angle); len = sqrt(u * u + v * v); u /= len; v /= len; glNormal3f(v, -u, 0.0); glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5); glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5); glNormal3f(cos(angle), sin(angle), 0.0); glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5); glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5); u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da); v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da); glNormal3f(v, -u, 0.0); glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); glNormal3f(cos(angle), sin(angle), 0.0); } glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5); glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5); glEnd(); glShadeModel(GL_SMOOTH); /* draw inside radius cylinder */ glBegin(GL_QUAD_STRIP); for (i = 0; i <= teeth; i++) { angle = i * 2.0 * M_PI / teeth; glNormal3f(-cos(angle), -sin(angle), 0.0); glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); } glEnd(); } static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0; static GLint gear1, gear2, gear3; static GLfloat angle = 0.0; static void draw(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glRotatef(view_rotx, 1.0, 0.0, 0.0); glRotatef(view_roty, 0.0, 1.0, 0.0); glRotatef(view_rotz, 0.0, 0.0, 1.0); glPushMatrix(); glTranslatef(-3.0, -2.0, 0.0); glRotatef(angle, 0.0, 0.0, 1.0); glCallList(gear1); glPopMatrix(); glPushMatrix(); glTranslatef(3.1, -2.0, 0.0); glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0); glCallList(gear2); glPopMatrix(); glPushMatrix(); glTranslatef(-3.1, 4.2, 0.0); glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0); glCallList(gear3); glPopMatrix(); glPopMatrix(); glutSwapBuffers(); Frames++; { GLint t = glutGet(GLUT_ELAPSED_TIME); if (t - T0 >= 5000) { GLfloat seconds = (t - T0) / 1000.0; GLfloat fps = Frames / seconds; printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps); T0 = t; Frames = 0; } } } static void idle(void) { angle += 2.0; glutPostRedisplay(); } /* change view angle, exit upon ESC */ /* ARGSUSED1 */ static void key(unsigned char k, int x, int y) { switch (k) { case 'z': view_rotz += 5.0; break; case 'Z': view_rotz -= 5.0; break; case 27: /* Escape */ exit(0); /* FIXME: Shutdown and free resources cleanly in ggiglut */ break; default: return; } glutPostRedisplay(); } /* change view angle */ /* ARGSUSED1 */ static void special(int k, int x, int y) { switch (k) { case GLUT_KEY_UP: view_rotx += 5.0; break; case GLUT_KEY_DOWN: view_rotx -= 5.0; break; case GLUT_KEY_LEFT: view_roty += 5.0; break; case GLUT_KEY_RIGHT: view_roty -= 5.0; break; default: return; } glutPostRedisplay(); } /* new window size or exposure */ static void reshape(int width, int height) { GLfloat h = (GLfloat) height / (GLfloat) width; glViewport(0, 0, (GLint) width, (GLint) height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.0, 0.0, -40.0); } static void init(void) { static GLfloat pos[4] = {5.0, 5.0, 10.0, 0.0}; static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0}; static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0}; static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0}; glLightfv(GL_LIGHT0, GL_POSITION, pos); glEnable(GL_CULL_FACE); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_DEPTH_TEST); /* make the gears */ gear1 = glGenLists(1); glNewList(gear1, GL_COMPILE); glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red); gear(1.0, 4.0, 1.0, 20, 0.7); glEndList(); gear2 = glGenLists(1); glNewList(gear2, GL_COMPILE); glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green); gear(0.5, 2.0, 2.0, 10, 0.7); glEndList(); gear3 = glGenLists(1); glNewList(gear3, GL_COMPILE); glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue); gear(1.3, 2.0, 0.5, 10, 0.7); glEndList(); glEnable(GL_NORMALIZE); } void visible(int vis) { if (vis == GLUT_VISIBLE) glutIdleFunc(idle); else glutIdleFunc(NULL); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); // glutInitWindowPosition(0, 0); // glutInitWindowSize(300, 300); glutCreateWindow("Gears"); init(); glutDisplayFunc(draw); glutReshapeFunc(reshape); glutKeyboardFunc(key); glutSpecialFunc(special); glutVisibilityFunc(visible); glutMainLoop(); return 0; }