void ClothDemo::Update(float duration)
{
if (duration <= 0.0f)
return;
cloth.addForce(Vector3(0.0, -0.02, 0.0));
cloth.addWindForce(Vector3(0.5, 0, 0.2));
cloth.timeStep(duration);
cloth.ballCollision(sphere);
}
/* display method called each frame*/
void display(void)
{
// calculating positions
ball_time++;
ball_pos.f[2] = cos(ball_time/50.0)*7;
cloth1.addForce(Vec3(0,-0.2,0)*TIME_STEPSIZE2); // add gravity each frame, pointing down
cloth1.windForce(Vec3(0.5,0,0.2)*TIME_STEPSIZE2); // generate some wind each frame
cloth1.timeStep(); // calculate the particle positions of the next frame
cloth1.ballCollision(ball_pos,ball_radius); // resolve collision with the ball
// drawing
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glDisable(GL_LIGHTING); // drawing some smooth shaded background - because I like it ;)
glBegin(GL_POLYGON);
glColor3f(0.8f,0.8f,1.0f);
glVertex3f(-200.0f,-100.0f,-100.0f);
glVertex3f(200.0f,-100.0f,-100.0f);
glColor3f(0.4f,0.4f,0.8f);
glVertex3f(200.0f,100.0f,-100.0f);
glVertex3f(-200.0f,100.0f,-100.0f);
glEnd();
glEnable(GL_LIGHTING);
glTranslatef(0.0f, 0.25f, z);
glRotatef(xRot, 1.0f, 0.0f, 0.0f);
glRotatef(yRot, 0.0f, 1.0f, 0.0f);
//glTranslatef(-6.5,6,-9.0f); // move camera out and center on the cloth
//glRotatef(25,0,1,0); // rotate a bit to see the cloth from the side
cloth1.drawShaded(myImage); // finally draw the cloth with smooth shading
glPushMatrix(); // to draw the ball we use glutSolidSphere, and need to draw the sphere at the position of the ball
glTranslatef(ball_pos.f[0],ball_pos.f[1],ball_pos.f[2]); // hence the translation of the sphere onto the ball position
glColor3f(0.4f,0.8f,0.5f);
glutSolidSphere(ball_radius-0.1,50,50); // draw the ball, but with a slightly lower radius, otherwise we could get ugly visual artifacts of cloth penetrating the ball slightly
glPopMatrix();
glutSwapBuffers();
glutPostRedisplay();
}