0,0 → 1,300 |
/* gears.c */ |
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/* |
* 3-D gear wheels. This program is in the public domain. |
* |
* Brian Paul |
*/ |
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#include <math.h> |
#include <stdlib.h> |
#include <stdio.h> |
#include <string.h> |
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#include <GL/glx.h> |
#include <GL/gl.h> |
#include "ui.h" |
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#ifndef M_PI |
# define M_PI 3.14159265 |
#endif |
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/* |
* 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; |
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r0 = inner_radius; |
r1 = outer_radius - tooth_depth/2.0; |
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 */ |
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 ); |
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(); |
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/* 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; |
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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(); |
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glNormal3f( 0.0, 0.0, -1.0 ); |
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/* 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 ); |
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(); |
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/* 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; |
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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(); |
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/* draw outward faces of teeth */ |
glBegin( GL_QUAD_STRIP ); |
for (i=0;i<teeth;i++) { |
angle = i * 2.0*M_PI / teeth; |
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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 ); |
} |
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glVertex3f( r1*cos(0), r1*sin(0), width*0.5 ); |
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 */ |
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(); |
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} |
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static GLfloat view_rotx=20.0, view_roty=30.0, view_rotz=0.0; |
static GLint gear1, gear2, gear3; |
static GLfloat angle = 0.0; |
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static GLuint limit; |
static GLuint count = 1; |
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void draw( void ) |
{ |
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); |
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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 ); |
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glPushMatrix(); |
glTranslatef( -3.0, -2.0, 0.0 ); |
glRotatef( angle, 0.0, 0.0, 1.0 ); |
glCallList(gear1); |
glPopMatrix(); |
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glPushMatrix(); |
glTranslatef( 3.1, -2.0, 0.0 ); |
glRotatef( -2.0*angle-9.0, 0.0, 0.0, 1.0 ); |
glCallList(gear2); |
glPopMatrix(); |
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glPushMatrix(); |
glTranslatef( -3.1, 4.2, 0.0 ); |
glRotatef( -2.0*angle-25.0, 0.0, 0.0, 1.0 ); |
glCallList(gear3); |
glPopMatrix(); |
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glPopMatrix(); |
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tkSwapBuffers(); |
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count++; |
if (count==limit) { |
exit(0); |
} |
} |
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void idle( void ) |
{ |
angle += 2.0; |
draw(); |
} |
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/* change view angle, exit upon ESC */ |
GLenum key(int k, GLenum mask) |
{ |
switch (k) { |
case KEY_UP: |
view_rotx += 5.0; |
return GL_TRUE; |
case KEY_DOWN: |
view_rotx -= 5.0; |
return GL_TRUE; |
case KEY_LEFT: |
view_roty += 5.0; |
return GL_TRUE; |
case KEY_RIGHT: |
view_roty -= 5.0; |
return GL_TRUE; |
case 'z': |
view_rotz += 5.0; |
return GL_TRUE; |
case 'Z': |
view_rotz -= 5.0; |
return GL_TRUE; |
case KEY_ESCAPE: |
exit(0); |
} |
return GL_FALSE; |
} |
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/* new window size or exposure */ |
void reshape( int width, int height ) |
{ |
GLfloat h = (GLfloat) height / (GLfloat) width; |
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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 ); |
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); |
} |
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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 }; |
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glLightfv( GL_LIGHT0, GL_POSITION, pos ); |
glEnable( GL_CULL_FACE ); |
glEnable( GL_LIGHTING ); |
glEnable( GL_LIGHT0 ); |
glEnable( GL_DEPTH_TEST ); |
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/* 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(); |
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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(); |
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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(); |
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glEnable( GL_NORMALIZE ); |
} |
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int main(int argc, char **argv) |
{ |
if (argc>1) { |
/* do 'n' frames then exit */ |
limit = atoi( argv[1] ) + 1; |
} |
else { |
limit = 0; |
} |
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return ui_loop(argc, argv, "gears"); |
} |
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