Another rotation instead of glRotate ???

OpenGL OpenGL: Advanced Coding
1

HI
I’m tryng to do a function that does exactly what glRotatef does.

Well, could you people check it, to see what’s wrong?

Shouldn’t this routines rotate the point in the x axis by 90 degrees, just like
glRotatef(90,1.0,0.0,0.0) ??
x1 = x;
y1 = (ycos(90))+(zsin(90));
z1 = (ycos(90))-(xsin(90));

2

convert your degrees to radians.

radians = (degrees / 360) * 2pi
= (degrees / 180) * pi

[This message has been edited by Attic Man (edited 08-04-2000).]

3

No, because you use x in the calculation of z.

Also, cos(90) == 0 and sin(90) == 1 (if you use degrees) but something completely different if you use radians (which your computer is doing).

4

Ok, i’v added the radians conversion, but still not working…,
any sugestions, please?

float Rad(float angle)
{
float PI = 3.14159265;
angle = (angle /180)*PI;
return angle;
}

x1 = x;
y1 = (ycos(Rad(90)))+(zsin(Rad(90)));
z1 = (ycos(Rad(90)))-(xsin(Rad(90)));

thanks
Bruno

5

In your z1 line, change the x to a z and then swap the positions of the z and y in that line too. At some point you might want to make that Rad function either an inline function or a macro, at least I would anyway.