65 lines
1.8 KiB
Markdown
65 lines
1.8 KiB
Markdown
# Camera Essentials
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There are two types of camera:
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1. A model-viewer camera
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2. A fly-through camera
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A camera involves
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1. A position in 3D space
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2. A forward direction
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3. A right direction
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4. An up direction
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Calculating a camera direction can be achieved using Euler angles, **pitch**, **yaw** and **roll** .
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- Pitch rotates the camera on the x axis
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- Think of a plane pointing its nose to the floor or to the sky
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- Yaw rotates the camera on the y axis
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- Think a plane moving the nose left to right keeping the wings parallel with the ground
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- Roll rotates the camera on the z axis
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- Think tilting the plane’s wings left and right, but not changing the direction of the nose
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#### Model-Viewer Camera
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This is a camera that can rotate around the model in a sphere.
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Changing the pitch of the camera makes the camera move upwards and point downwards, here the camera moves around the sphere where the direction is always towards the model
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The camera can also move back and forwards, making the sphere bigger or smaller.
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$$
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\begin{aligned}
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p_x = &\cos\theta * \cos\alpha \\
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p_y = &\sin\alpha \\
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p_z = &\sin\theta * \cos\alpha
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\end{aligned}
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$$
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#### Fly-Through Camera
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The camera has a position in world space and a focus direction `front`, which can be focused on the model or not.
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We can move this kind of camera, forward, backward, left and right along with pitch, roll and yaw.
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The camera is at the center of the sphere, and the model moves around the edge of the sphere.
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A unit vector points from the camera to the model as the front direction of the camera
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We can move the camera forwards and backwards by
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```c
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pos += front //forwards
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pos -= front //backwards
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pos += right //move right
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pos -= right //move left
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```
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