Projection Matrix

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Projection matrix three main component:

• Aspect ratio
• Field Of View (FOV angle)
• Normalization

Aspect ratio

We scale, shink thing on x-axis.

FOV:

Talking about 'how much object can we see?'

• The bigger FOV, the object have to be smaller.
• The smaller FOV, the object have to be bigger.

so, we inverse the scale factor to: 1 / tan(angle/ 2)

Normalizing

• zfar: the maximun value we can disapy
• znear: the closest value we can saw.

So zfar / (zfar - znear), zfar over the total Z distance give us normalized value. And at the end we subtract the offset.

The flow of projection: