[BlindMath] Do Two line segments intersect?

[Jonathan Fine]

Hi Chris

I'm happy to be your sighted assistant for this. I'll learn something from
it.

Here's a start, from my phone.

To understand the algorithm you will need to know what it is that the
determinant calculates.

To implement the algorithm you will need to know how to compute a
determinant.

You might also need to know something about the hazards of floating point
arithmetic.

All the above are equally true for sighted and blind.

You quoted some determinants from stack overflow. Unfortunately they've
been written as ASCII art, and you've misread them.

In ASCII art the basic 2x2 determinant is

| a b |
| c d |

It's value is (a*d - b*c).

The quote from stack overflow you should read as columns, not rows.

All this might not be enough to help you. Please let me know how you get
on, and I'll respond further tomorrow.

Best wishes

Jonathan