Lecture 13 - Review of Pitch and Yaw

Announcements:

P4 due Monday
Lab 8 (pitch and yaw) due today

Review of Pitch and Yaw

Some tidbits that are the most important:

Recall that we want to use the glm::LookAt method to generate. Lecture 12 - Pitch and Yaw Camera#^c529c8.
The origin is the eye of the camera. Part of moving the world to where the eye is centered is part of the view transform V as per

$[\begin{matrix} u_{x} & u_{y} & u_{z} & 0 \\ v_{x} & v_{y} & v_{z} & 0 \\ w_{x} & w_{y} & w_{z} & 0 \\ 0 & 0 & 0 & 1 \end{matrix}] [\begin{matrix} 1 & 0 & 0 & - e_{x} \\ 0 & 1 & 0 & - e_{y} \\ 0 & 0 & 1 & - e_{z} \\ 0 & 0 & 0 & 1 \end{matrix}]$

where the first applied matrix is the translation that helps us move the world to the eye coordinates.

You'll need to be able to compute $w$ or $u$ so you can dolly or strafe in P4.

Issues with This

If your gaze $v_{v i e w}$ points in the direction of $v_{u p}$ , then the cross product's don't work from Lecture 12 - Pitch and Yaw Camera#^df77d6. Hence, when you look straight up your world will start to spin.

So when you look straight up in a game or otherwise, you can just restrict it. Even if it's something really small like $ε = 0.0001$ or something like that, you can have the impression that it looks like you're looking straight up:

Things for P4

For the lab we just put the eye at the origin. In lab, you'll have $θ \in (0, 360)$ degrees while we have:

- 85 \leq α \leq 85

To update $α$ we want to do:

alpha += deltaY * scale;
beta += deltaX * scale;

Make sure for WASD that, not only for updating the eye position, we need to update the look-at point too.