gluLookAt alternative doesn't work
- by Brammie
Hey guys.
I'm trying to calculate a lookat matrix myself, instead of using gluLookAt().
My problem is that my matrix doesn't work. using the same parameters on gluLookAt does work however.
my way of creating a lookat matrix:
Vector3 Eye, At, Up; //these should be parameters =)
Vector3 zaxis = At - Eye; zaxis.Normalize();
Vector3 xaxis = Vector3::Cross(Up, zaxis); xaxis.Normalize();
Vector3 yaxis = Vector3::Cross(zaxis, xaxis); yaxis.Normalize();
float r[16] =
{
xaxis.x, yaxis.x, zaxis.x, 0,
xaxis.y, yaxis.y, zaxis.y, 0,
xaxis.z, yaxis.z, zaxis.z, 0,
0, 0, 0, 1,
};
Matrix Rotation;
memcpy(Rotation.values, r, sizeof(r));
float t[16] =
{
1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
-Eye.x, -Eye.y, -Eye.z, 1,
};
Matrix Translation;
memcpy(Translation.values, t, sizeof(t));
View = Rotation * Translation; // i tried reversing this as well (translation*rotation)
now, when i try to use this matrix be calling glMultMatrixf, nothing shows up in my engine, while using the same eye, lookat and up values on gluLookAt works perfect as i said before.
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMultMatrixf(View);
the problem must be in somewhere in the code i posted here, i know the problem is not in my Vector3/Matrix classes, because they work fine when creating a projection matrix.
