0

Hi everyone, I need some help with the lookat matrix...

This is my code

```
Matrix Matrix::CreateLookAt(Vector3 eye, Vector3 target, Vector3 up)
{
Vector3 forward = target - eye;
forward.normalize();
Vector3 side = Vector3::cross(forward, up);
side.normalize();
up = Vector3::cross(side, forward);
Matrix m; // Defaults to identity matrix
m.m11 = side.x; m.m12 = up.x; m.m13 = -forward.x;
m.m21 = side.y; m.m22 = up.y; m.m23 = -forward.y;
m.m31 = side.z; m.m32 = up.z; m.m33 = -forward.z;
m.m14 = -eye.x;
m.m24 = -eye.y;
m.m34 = -eye.z;
return m;
}
```

And this is the mesa opensource opengl code

```
void GLAPIENTRY
gluLookAt(GLdouble eyex, GLdouble eyey, GLdouble eyez, GLdouble centerx,
GLdouble centery, GLdouble centerz, GLdouble upx, GLdouble upy,
GLdouble upz)
{
float forward[3], side[3], up[3];
GLfloat m[4][4];
forward[0] = centerx - eyex;
forward[1] = centery - eyey;
forward[2] = centerz - eyez;
up[0] = upx;
up[1] = upy;
up[2] = upz;
normalize(forward);
/* Side = forward x up */
cross(forward, up, side);
normalize(side);
/* Recompute up as: up = side x forward */
cross(side, forward, up);
__gluMakeIdentityf(&m[0][0]);
m[0][0] = side[0];
m[1][0] = side[1];
m[2][0] = side[2];
m[0][1] = up[0];
m[1][1] = up[1];
m[2][1] = up[2];
m[0][2] = -forward[0];
m[1][2] = -forward[1];
m[2][2] = -forward[2];
glMultMatrixf(&m[0][0]);
glTranslated(-eyex, -eyey, -eyez);
}
```

I started out with my own version which didn't work, and now i try to follow mesa's code but still failed. Can help me see what is wrong with my maths at all?

All my cross products are correct.

Unfortunately i cannot find the source for glTranslated() but assumed it is just the 4th column values applied. But I am obviously wrong. But that's not the only error, as can seen when I compare both matrix after the gluLookAt function.

*Edited 6 Years Ago by jakesee*: n/a