xenocara/dist/Mesa/progs/xdemos/vgears.c

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2006-11-25 11:56:37 -07:00
/* $ID$ */
/*
* Spinning gears demo for Linux SVGA/Mesa interface in 32K color mode.
*
* Compile with: gcc vgears.c -I../include -L../lib -lMesaGL -lX11 -lXext
* -lvga -lm -o vgears
*
* This program is in the public domain.
* Brian Paul, January 1996
*/
#include <vga.h>
#include <math.h>
#include "GL/svgamesa.h"
#include "GL/gl.h"
int width = 800, height = 600;
SVGAMesaContext vmc;
/*
* 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 );
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 );
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 GLuint limit;
static GLuint count = 1;
static void draw( void )
{
angle += 2.0;
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();
SVGAMesaSwapBuffers();
}
static void init( void )
{
static GLfloat pos[4] = {5.0, 5.0, 10.0, 1.0 };
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 };
GLfloat w = (float) width / (float) height;
GLfloat h = 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 );
glViewport( 0, 0, width, height );
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (width>height) {
GLfloat w = (GLfloat) width / (GLfloat) height;
glFrustum( -w, w, -1.0, 1.0, 5.0, 60.0 );
}
else {
GLfloat h = (GLfloat) height / (GLfloat) width;
glFrustum( -1.0, 1.0, -h, h, 5.0, 60.0 );
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef( 0.0, 0.0, -40.0 );
}
void setup( void )
{
vga_init();
vga_setmode(G800x600x32K);
/* gl_setcontextvga(G800x600x32K);*/
vmc = SVGAMesaCreateContext(GL_TRUE);
SVGAMesaMakeCurrent( vmc );
}
void end( void )
{
SVGAMesaDestroyContext( vmc );
vga_setmode( TEXT );
}
int main( int argc, char *argv[] )
{
int i;
setup();
init();
for (i=0;i<4;i++) {
draw(); /*SVGAMesaSwapBuffers();*/
}
end();
return 0;
}