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/*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* This is a port of the infamous "glxgears" demo to straight EGL
* Port by Dane Rushton 10 July 2005
*
* No command line options.
* Program runs for 5 seconds then exits, outputing framerate to console
*/
#include <math.h>
#include <GL/gl.h>
#include <EGL/egl.h>
#include "eglut.h"
static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
static GLint gear1, gear2, gear3;
static GLfloat angle = 0.0;
/*
*
* 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 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();
}
static void
idle(void)
{
static double t0 = -1.;
double dt, t = eglutGet(EGLUT_ELAPSED_TIME) / 1000.0;
if (t0 < 0.0)
t0 = t;
dt = t - t0;
t0 = t;
angle += 70.0 * dt; /* 70 degrees per second */
angle = fmod(angle, 360.0); /* prevents eventual overflow */
eglutPostRedisplay();
}
/* 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);
}
int
main(int argc, char *argv[])
{
eglutInitWindowSize(300, 300);
eglutInitAPIMask(EGLUT_OPENGL_BIT);
eglutInit(argc, argv);
eglutCreateWindow("eglgears");
eglutIdleFunc(idle);
eglutReshapeFunc(reshape);
eglutDisplayFunc(draw);
init();
glDrawBuffer(GL_BACK);
eglutMainLoop();
return 0;
}
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