Miscellany

// Julien Pilet, Sept. 2008#include <OpenCV/cv.h>#include "Meddle/elasticchainondefm.h"namespace Meddle {/* ctor */ElasticChain::ElasticChain(unsigned int npts, float x, float y,    Model::Animation::Handler *animation):	m_npts(npts),	m_first(true),	m_animation(animation){	m_elastics  = new t_elastic[m_npts - 1];	m_pts = new t_point[m_npts];	memset(m_pts, 0, m_npts * sizeof(t_point));	// orientation et force de la gravite	gravity[0] = 0;	gravity[1] = -800;	float dy = 2 / m_npts; // 2/m_npts espace entre les points du spaghetti	for (int i = 0; i < m_npts; i++) {		m_pts[i].mass   = .002;		// poids des maillons intermediaires		m_pts[i].pos[0] = x;		m_pts[i].pos[1] = y + i*dy;	}	m_pts[0].flags = 10;	m_pts[m_npts - 1].mass = .02;	for (int i = 0;i < m_npts - 1; i++) {		m_elastics[i].p1 = m_pts + i;		m_elastics[i].p2 = m_pts + i + 1;		m_elastics[i].factor = 2; //2 ressort plus ou moins rigide		m_elastics[i].len = dy;	}	m_last.start();}/* dtor */ElasticChain::~ElasticChain(){	delete[] (m_pts);	delete[] (m_elastics);}voidElasticChain::draw(float x, float y){	if (m_first) {		m_first = false;		return;	}	float dtime = m_last.elapsed();	m_pts[0].pos[0] = x;	m_pts[0].pos[1] = y;	dtime = dtime / 32;	for (int i = 0;i < 32; i++) {		zero_forces(m_pts, m_npts);		calc_forces(m_elastics, m_npts - 1);		advance(m_pts, m_npts, dtime);	}	m_animation->texturize();	m_animation->texture.enable();	double width = 20;  //20 LARGEUR de la chaine dessine	glBegin(GL_TRIANGLES);	glColor4f(1, 1, 1, 1);	int ndiv = 1;	int tot = (m_npts - 1) * ndiv;	int k = 0;	for (int i = 0;i < m_npts - 1; i++) {		for (int j = 0;j < ndiv; j++, k++) {			float t = j / (float)ndiv;			float r[2];			float dt[2];			float nr[2], ndt[2];			splineCompute(t,2, (i>0? m_pts[i-1].pos:0), m_pts[i].pos, m_pts[i+1].pos,					(i<m_npts-2? m_pts[i+2].pos:0), r, dt);			splineCompute(t+1.0f/ndiv,2, (i>0? m_pts[i-1].pos:0), m_pts[i].pos, m_pts[i+1].pos,					(i<m_npts-2? m_pts[i+2].pos:0), nr, ndt);			float w = width /sqrt(dt[0]*dt[0]+dt[1]*dt[1]);			dt[0] *= w;			dt[1] *= w;			w = width/sqrt(ndt[0]*ndt[0]+ndt[1]*ndt[1]);			ndt[0] *= w;			ndt[1] *= w;			/*float a[2]= {r[0]-dt[1],r[1]+dt[0]};			  float b[2]= {r[0]+dt[1],r[1]-dt[0]};			  float na[2]= {nr[0]-ndt[1],nr[1]+ndt[0]};			  float nb[2]= {nr[0]+ndt[1],nr[1]-ndt[0]};*/			float a[2]= {r[0]+80,r[1]-80};			float b[2]= {r[0]-80,r[1]-80};			float na[2]= {r[0]+80,r[1]+80};			float nb[2]= {r[0]-80,r[1]+80};			float tex = (float)k/(float)tot;			float texn = (float)(k+1)/(float)tot;			glTexCoord2f(0,tex);			glVertex2fv(a);			glTexCoord2f(1,tex);			glVertex2fv(b);			glTexCoord2f(0,texn);			glVertex2fv(na);			glTexCoord2f(0,texn);			glVertex2fv(na);			glTexCoord2f(1,tex);			glVertex2fv(b);			glTexCoord2f(1,texn);			glVertex2fv(nb);		}	}	glEnd();	m_animation->texture.disable();	m_last.restart();}} // namespace Meddle