FoX_*D i E*

04-09-2010, 09:40 AM

Hello,

First, sorry for my English, I'm a French student.

I'm drawing a quarter cylinder and I want it to be correctly lighted.

I simplify the code to make is more readable.

This think works:

glBegin(GL_QUAD_STRIP);

for (i=-90; i<=0; i+=precision)

{

float angle_radians = i * M_PI / (float)180;

float x = rayon * (float)cos(angle_radians);

float z = rayon * (float)sin(angle_radians);

glNormal3f( 1., 0., 1. );

glVertex3f(x,0,z);

glVertex3f(x,hauteur,z);

}

glEnd();

But I want the light rendering being normal to little rectangles drawn. What follows does not work, it's lighten as a grid:

glBegin(GL_QUAD_STRIP);

for (i=-90; i<=0; i+=precision)

{

float angle_radians = i * M_PI / (float)180;

float x = rayon * (float)cos(angle_radians);

float z = rayon * (float)sin(angle_radians);

//glNormal3f( 1., 0., 1. );

glNormal3f(cos(i),0,sin(i));

glVertex3f(x,0,z);

glVertex3f(x,hauteur,z);

}

glEnd();

By the way, if you know a glut function that draw a part of cylinder, I'm interested!

First, sorry for my English, I'm a French student.

I'm drawing a quarter cylinder and I want it to be correctly lighted.

I simplify the code to make is more readable.

This think works:

glBegin(GL_QUAD_STRIP);

for (i=-90; i<=0; i+=precision)

{

float angle_radians = i * M_PI / (float)180;

float x = rayon * (float)cos(angle_radians);

float z = rayon * (float)sin(angle_radians);

glNormal3f( 1., 0., 1. );

glVertex3f(x,0,z);

glVertex3f(x,hauteur,z);

}

glEnd();

But I want the light rendering being normal to little rectangles drawn. What follows does not work, it's lighten as a grid:

glBegin(GL_QUAD_STRIP);

for (i=-90; i<=0; i+=precision)

{

float angle_radians = i * M_PI / (float)180;

float x = rayon * (float)cos(angle_radians);

float z = rayon * (float)sin(angle_radians);

//glNormal3f( 1., 0., 1. );

glNormal3f(cos(i),0,sin(i));

glVertex3f(x,0,z);

glVertex3f(x,hauteur,z);

}

glEnd();

By the way, if you know a glut function that draw a part of cylinder, I'm interested!