/* calculates normal to the triangle designated by v1, v2, v3 */
void triagnormal(float v1[3], float v2[3], float v3[3], float norm[3])
{
float vec1[3], vec2[3];
vec1[0] = v3[0] - v1[0];
vec2[0] = v2[0] - v1[0];
vec1[1] = v3[1] - v1[1];
vec2[1] = v2[1] - v1[1];
vec1[2] = v3[2] - v1[2];
vec2[2] = v2[2] - v1[2];
ncrossprod(vec2, vec1, norm);
}
/*
* I took the idea of tracking eye position in absolute
* coords and direction looking in Polar form from denis
*/
void FlyLookFrom(GLfloat x, GLfloat y, GLfloat z, GLfloat az, GLfloat el)
{
float lookat[3], perp[3], up[3];
lookat[0] = sin(TORAD(az))*cos(TORAD(el));
lookat[1] = sin(TORAD(el));
lookat[2] = -cos(TORAD(az))*cos(TORAD(el));
normalize(lookat);
perp[0] = lookat[2];
perp[1] = 0;
perp[2] = -lookat[0];
normalize(perp);
ncrossprod(lookat, perp, up);
gluLookAt(x, y, z,
x+lookat[0], y+lookat[1], z+lookat[2],
up[0], up[1], up[2]);
}
