/* Une courbe de BSpline */
/* */
/* Auteur: Nicolas JANEY */
/* nicolas.janey@univ-fcomte.fr */
/* Decembre 2009 */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>
typedef struct coord_3D {
GLfloat x,y,z,w; } coord_3D;
typedef struct lignePolygonale {
int n;
coord_3D *p; } lignePolygonale;
typedef float matrice[4][4];
static float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static GLfloat vert[4] = { 0.0F,1.0F,0.0F,1.0F };
static GLfloat bleu[4] = { 0.0F,0.0F,1.0F,1.0F };
static GLfloat cyan[4] = { 0.0F,1.0F,1.0F,1.0F };
static GLfloat magenta[4] = { 1.0F,0.0F,1.0F,1.0F };
static GLfloat jaune[4] = { 1.0F,1.0F,0.0F,1.0F };
static GLfloat rouge[4] = { 1.0F,0.0F,0.0F,1.0F };
static coord_3D ptsi[28] = {
{-3.0,-3.0,-3.0,1.0},{-3.0, 3.0,-3.0,1.0},
{ 3.0, 3.0,-3.0,1.0},{ 3.0,-3.0,-3.0,1.0},
{-3.0,-3.0,-2.0,1.0},{-3.0, 3.0,-2.0,1.0},
{ 3.0, 3.0,-2.0,1.0},{ 3.0,-3.0,-2.0,1.0},
{-3.0,-3.0,-1.0,1.0},{-3.0, 3.0,-1.0,1.0},
{ 3.0, 3.0,-1.0,1.0},{ 3.0,-3.0,-1.0,1.0},
{-3.0,-3.0, 0.0,1.0},{-3.0, 3.0, 0.0,1.0},
{ 3.0, 3.0, 0.0,1.0},{ 3.0,-3.0, 0.0,1.0},
{-3.0,-3.0, 1.0,1.0},{-3.0, 3.0, 1.0,1.0},
{ 3.0, 3.0, 1.0,1.0},{ 3.0,-3.0, 1.0,1.0},
{-3.0,-3.0, 2.0,1.0},{-3.0, 3.0, 2.0,1.0},
{ 3.0, 3.0, 2.0,1.0},{ 3.0,-3.0, 2.0,1.0},
{-3.0,-3.0, 3.0,1.0},{-3.0, 3.0, 3.0,1.0},
{ 3.0, 3.0, 3.0,1.0},{ 3.0,-3.0, 3.0,1.0} };
static coord_3D pts[28];
static int aff = 28;
static int nbp = 300;
static int m = 0;
static int p = 0;
static lignePolygonale pl = { 28,(coord_3D *) &pts[0] };
matrice m1 = { -0.1666666F, 0.5F, -0.5F, 0.1666666F,
0.5F ,-1.0F, 0.5F, 0.0F,
-0.5F , 0.0F, 0.5F, 0.0F,
0.1666666F, 0.6666666F, 0.1666666F,0.0F } ;
matrice m2 = { -0.5F, 1.5F,-1.5F, 0.5F,
1.0F,-2.5F, 2.0F,-0.5F,
-0.5F, 0.0F, 0.5F, 0.0F,
0.0F, 1.0F, 0.0F, 0.0F } ;
void calculPoint(coord_3D *p,coord_3D *g,float t,matrice m) {
float tt[4],ttt[4] ;
tt[0] = t*t*t ;
tt[1] = t*t ;
tt[2] = t ;
tt[3] = 1.0F ;
for ( int j = 0 ; j < 4 ; j++ ) {
ttt[j] = 0 ;
for ( int k = 0 ; k < 4 ; k++ )
ttt[j] += tt[k] * m[k][j] ; }
for ( int j = 0 ; j < 4 ; j++ ) {
p->x += ttt[j] * g[j].x ;
p->y += ttt[j] * g[j].y ;
p->z += ttt[j] * g[j].z ; }
p->w = 1.0F;
}
void bspline(lignePolygonale *p,int n,lignePolygonale *b,matrice m) {
b->n = n;
b->p =(coord_3D *) calloc(n,sizeof(coord_3D));
for ( int i = 0 ; i < n ; i++ ) {
float t =(float) (p->n-3)*i/(n-1);
int crv = t;
t -= crv;
if ( crv == p->n-3 ) {
crv = p->n-4;
t = 1.0F; }
calculPoint(&b->p[i],&p->p[crv],t,m); }
}
void display(void) {
int i;
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(rx,1.0F,0.0F,0.0F);
glRotatef(ry,0.0F,1.0F,0.0F);
glRotatef(rz,0.0F,0.0F,1.0F);
glPointSize(5.0);
glColor4fv(jaune);
glBegin(GL_POINTS);
for( i = 0 ; i < aff ; i++ )
glVertex3fv((GLfloat *) &pts[i]);
glEnd();
glColor4fv(rouge);
glBegin(GL_LINE_STRIP);
for( i = 0 ; i < aff ; i++ )
glVertex3fv((GLfloat *) &pts[i]);
glEnd();
glPointSize(3.0);
lignePolygonale bsp;
bspline(&pl,nbp,&bsp,(m) ? m2 : m1);
glBegin(GL_POINTS);
for ( i = 0 ; i < bsp.n ; i++ ) {
float t =(float) (pl.n-3)*i/(bsp.n-1);
int crv = t;
if ( crv == pl.n-3 ) {
crv = pl.n-4; }
switch (crv%4) {
case 0 :
glColor4fv(magenta);
break;
case 1 :
glColor4fv(cyan);
break;
case 2 :
glColor4fv(vert);
break;
case 3 :
glColor4fv(bleu);
break; }
glVertex3fv((GLfloat *)&bsp.p[i]); }
glEnd();
free(bsp.p);
glPopMatrix();
glFlush();
glutSwapBuffers();
int error = glGetError();
if ( error != GL_NO_ERROR )
printf("Erreur OpenGL\n",error);
}
/* Fonction executee lorsqu'aucun evenement */
/* n'est en file d'attente */
void idle(void) {
rx += 0.4256F;
ry += 0.6117F;
rz += 0.4174F;
glutPostRedisplay() ;
}
/* Fonction executee lors d'un changement */
/* de la taille de la fenetre OpenGL */
void reshape(int x,int y) {
glViewport(0,0,x,y);
glMatrixMode(GL_PROJECTION) ;
glLoadIdentity() ;
gluPerspective(65.0F,(float) x/y,1.0,40.0) ;
glMatrixMode(GL_MODELVIEW) ;
glLoadIdentity() ;
gluLookAt(0.0,0.0,10.0,0.0,0.0,0.0,0.0,1.0,0.0);
}
/* Fonction executee lors de l'appui */
/* d'une touche de curseur ou d'une touche */
/* page up ou page down */
void special(int key,int x,int y) {
switch(key) {
case GLUT_KEY_UP :
rx++;
glutPostRedisplay() ;
break;
case GLUT_KEY_DOWN :
rx--;
glutPostRedisplay() ;
break;
case GLUT_KEY_LEFT :
ry++;
glutPostRedisplay() ;
break;
case GLUT_KEY_RIGHT :
ry--;
glutPostRedisplay() ;
break;
case GLUT_KEY_PAGE_UP :
rz++;
glutPostRedisplay() ;
break;
case GLUT_KEY_PAGE_DOWN :
rz--;
glutPostRedisplay() ;
break; }
}
void myinit(void) {
for ( int i = 0 ; i < 28 ; i++ )
pts[i] = ptsi[i];
glClearColor(0.0,0.0,0.0,1.0);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_FLAT);
glDepthFunc(GL_LESS);
glEnable(GL_AUTO_NORMAL);
glEnable(GL_NORMALIZE);
}
void keyboard(unsigned char key,int x,int y) {
switch ( key ) {
case 43 :
nbp++;
glutPostRedisplay();
break;
case 45 :
nbp--;
if ( nbp < 2 )
nbp = 2;
glutPostRedisplay();
break;
case 0x0D :
p = !p;
for ( int i = 0 ; i < 28 ; i++ ) {
pts[i].x = ptsi[i].x + ((p) ? -0.5F + (rand()%100)/100.0F : 0.0F);
pts[i].y = ptsi[i].y + ((p) ? -0.5F + (rand()%100)/100.0F : 0.0F);
pts[i].z = ptsi[i].z + ((p) ? -0.5F + (rand()%100)/100.0F : 0.0F); }
glutPostRedisplay();
break;
case 0x1B :
exit(0);
break;
case 0x20 :
{ static int anim = 0;
anim = !anim;
glutIdleFunc(( anim ) ? idle : NULL); }
break;
case 'm' :
m = !m;
glutPostRedisplay();
break; }
}
int main(int argc,char **argv) {
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
glutInitWindowSize(300,300);
glutInitWindowPosition(50,50);
glutCreateWindow("Courbe BSpline");
myinit();
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutSpecialFunc(special);
glutDisplayFunc(display);
glutMainLoop();
return(0);
}
RETOUR