406 lines
9.6 KiB
C
406 lines
9.6 KiB
C
/*
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* 3-D gear wheels. This program is in the public domain.
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*
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* Command line options:
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* -info print GL implementation information
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* -exit automatically exit after 30 seconds
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*
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*
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* Brian Paul
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*/
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/* Conversion to GLUT by Mark J. Kilgard */
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#include <math.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <GL/glut.h>
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#ifndef M_PI
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#define M_PI 3.14159265
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#endif
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static GLint T0 = 0;
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static GLint Frames = 0;
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static GLint autoexit = 0;
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static GLint win = 0;
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static GLboolean Visible = GL_TRUE;
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static GLboolean Animate = GL_TRUE;
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static GLfloat viewDist = 40.0;
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/**
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Draw a gear wheel. You'll probably want to call this function when
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building a display list since we do a lot of trig here.
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Input: inner_radius - radius of hole at center
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outer_radius - radius at center of teeth
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width - width of gear
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teeth - number of teeth
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tooth_depth - depth of tooth
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**/
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static void
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gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
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GLint teeth, GLfloat tooth_depth)
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{
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GLint i;
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GLfloat r0, r1, r2;
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GLfloat angle, da;
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GLfloat u, v, len;
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r0 = inner_radius;
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r1 = outer_radius - tooth_depth / 2.0;
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r2 = outer_radius + tooth_depth / 2.0;
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da = 2.0 * M_PI / teeth / 4.0;
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glShadeModel(GL_FLAT);
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glNormal3f(0.0, 0.0, 1.0);
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/* draw front face */
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glBegin(GL_QUAD_STRIP);
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for (i = 0; i <= teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
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glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
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if (i < teeth) {
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glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
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}
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}
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glEnd();
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/* draw front sides of teeth */
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glBegin(GL_QUADS);
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da = 2.0 * M_PI / teeth / 4.0;
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for (i = 0; i < teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
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glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
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glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
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}
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glEnd();
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glNormal3f(0.0, 0.0, -1.0);
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/* draw back face */
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glBegin(GL_QUAD_STRIP);
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for (i = 0; i <= teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
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glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
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if (i < teeth) {
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
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glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
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}
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}
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glEnd();
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/* draw back sides of teeth */
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glBegin(GL_QUADS);
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da = 2.0 * M_PI / teeth / 4.0;
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for (i = 0; i < teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
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glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
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glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
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glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
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}
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glEnd();
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/* draw outward faces of teeth */
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glBegin(GL_QUAD_STRIP);
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for (i = 0; i < teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
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glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
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u = r2 * cos(angle + da) - r1 * cos(angle);
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v = r2 * sin(angle + da) - r1 * sin(angle);
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len = sqrt(u * u + v * v);
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u /= len;
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v /= len;
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glNormal3f(v, -u, 0.0);
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glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
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glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
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glNormal3f(cos(angle), sin(angle), 0.0);
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glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
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glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
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u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
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v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
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glNormal3f(v, -u, 0.0);
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
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glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
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glNormal3f(cos(angle), sin(angle), 0.0);
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}
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glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
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glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
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glEnd();
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glShadeModel(GL_SMOOTH);
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/* draw inside radius cylinder */
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glBegin(GL_QUAD_STRIP);
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for (i = 0; i <= teeth; i++) {
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angle = i * 2.0 * M_PI / teeth;
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glNormal3f(-cos(angle), -sin(angle), 0.0);
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glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
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glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
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}
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glEnd();
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}
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static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
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static GLint gear1, gear2, gear3;
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static GLfloat angle = 0.0;
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static void
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cleanup(void)
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{
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glDeleteLists(gear1, 1);
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glDeleteLists(gear2, 1);
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glDeleteLists(gear3, 1);
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glutDestroyWindow(win);
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}
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static void
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draw(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix();
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glTranslatef(0.0, 0.0, -viewDist);
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glRotatef(view_rotx, 1.0, 0.0, 0.0);
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glRotatef(view_roty, 0.0, 1.0, 0.0);
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glRotatef(view_rotz, 0.0, 0.0, 1.0);
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glPushMatrix();
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glTranslatef(-3.0, -2.0, 0.0);
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glRotatef(angle, 0.0, 0.0, 1.0);
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glCallList(gear1);
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glPopMatrix();
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glPushMatrix();
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glTranslatef(3.1, -2.0, 0.0);
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glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
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glCallList(gear2);
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glPopMatrix();
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glPushMatrix();
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glTranslatef(-3.1, 4.2, 0.0);
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glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
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glCallList(gear3);
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glPopMatrix();
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glPopMatrix();
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glutSwapBuffers();
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Frames++;
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{
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GLint t = glutGet(GLUT_ELAPSED_TIME);
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if (t - T0 >= 5000) {
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GLfloat seconds = (t - T0) / 1000.0;
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GLfloat fps = Frames / seconds;
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printf("%d frames in %6.3f seconds = %6.3f FPS\n", Frames, seconds, fps);
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fflush(stdout);
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T0 = t;
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Frames = 0;
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if ((t >= 999.0 * autoexit) && (autoexit)) {
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cleanup();
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exit(0);
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}
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}
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}
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}
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static void
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idle(void)
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{
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static double t0 = -1.;
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double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
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if (t0 < 0.0)
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t0 = t;
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dt = t - t0;
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t0 = t;
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angle += 70.0 * dt; /* 70 degrees per second */
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angle = fmod(angle, 360.0); /* prevents eventual overflow */
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glutPostRedisplay();
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}
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static void
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update_idle_func(void)
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{
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if (Visible && Animate)
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glutIdleFunc(idle);
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else
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glutIdleFunc(NULL);
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}
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/* change view angle, exit upon ESC */
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/* ARGSUSED1 */
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static void
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key(unsigned char k, int x, int y)
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{
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switch (k) {
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case 'z':
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view_rotz += 5.0;
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break;
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case 'Z':
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view_rotz -= 5.0;
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break;
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case 'd':
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viewDist += 1.0;
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break;
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case 'D':
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viewDist -= 1.0;
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break;
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case 'a':
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Animate = !Animate;
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update_idle_func();
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break;
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case 27: /* Escape */
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cleanup();
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exit(0);
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break;
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default:
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return;
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}
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glutPostRedisplay();
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}
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/* change view angle */
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/* ARGSUSED1 */
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static void
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special(int k, int x, int y)
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{
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switch (k) {
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case GLUT_KEY_UP:
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view_rotx += 5.0;
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break;
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case GLUT_KEY_DOWN:
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view_rotx -= 5.0;
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break;
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case GLUT_KEY_LEFT:
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view_roty += 5.0;
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break;
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case GLUT_KEY_RIGHT:
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view_roty -= 5.0;
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break;
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default:
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return;
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}
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glutPostRedisplay();
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}
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/* new window size or exposure */
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static void
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reshape(int width, int height)
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{
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GLfloat h = (GLfloat) height / (GLfloat) width;
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glViewport(0, 0, (GLint) width, (GLint) height);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glFrustum(-1.0, 1.0, -h, h, 5.0, 200.0);
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glMatrixMode(GL_MODELVIEW);
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}
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static void
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init(int argc, char *argv[])
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{
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static GLfloat pos[4] = {5.0, 5.0, 10.0, 0.0};
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static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0};
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static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0};
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static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};
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GLint i;
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glLightfv(GL_LIGHT0, GL_POSITION, pos);
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glEnable(GL_CULL_FACE);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glEnable(GL_DEPTH_TEST);
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/* make the gears */
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gear1 = glGenLists(1);
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glNewList(gear1, GL_COMPILE);
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glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
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gear(1.0, 4.0, 1.0, 20, 0.7);
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glEndList();
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gear2 = glGenLists(1);
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glNewList(gear2, GL_COMPILE);
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glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
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gear(0.5, 2.0, 2.0, 10, 0.7);
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glEndList();
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gear3 = glGenLists(1);
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glNewList(gear3, GL_COMPILE);
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glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
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gear(1.3, 2.0, 0.5, 10, 0.7);
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glEndList();
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glEnable(GL_NORMALIZE);
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for ( i=1; i<argc; i++ ) {
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if (strcmp(argv[i], "-info")==0) {
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printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
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printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
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printf("GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
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printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
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}
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else if ( strcmp(argv[i], "-exit")==0) {
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autoexit = 30;
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printf("Auto Exit after %i seconds.\n", autoexit );
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}
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}
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}
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static void
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visible(int vis)
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{
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Visible = vis;
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update_idle_func();
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}
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int main(int argc, char *argv[])
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{
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glutInit(&argc, argv);
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glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(300, 300);
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win = glutCreateWindow("Gears");
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init(argc, argv);
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glutDisplayFunc(draw);
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glutReshapeFunc(reshape);
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glutKeyboardFunc(key);
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glutSpecialFunc(special);
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glutVisibilityFunc(visible);
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update_idle_func();
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glutMainLoop();
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return 0; /* ANSI C requires main to return int. */
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}
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