Camera matrix from basic principles.
Derivation of a camera matrix general enough to be used for stereo rendering, and it's inverse. This problem is used to motivate and discuss projective geometry.
A neat vector expression for the direction of refraction
Derivation of an economical vector expression for the direction of refraction.
Fast quaternion math in shaders
I derive a few of the handiest quaternion functions in a way suited for implementation in shader languages.
Round-off error propagation.
I prove some simple rules of thumb for how many decimals to keep when multiplying and dividing numbers.
Working out some expressions for grids.
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