Modern Math Reflect

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Reflect

Reflects a vector off a surface, given the surface's normalised normal.

Syntax

Reflect( byref v as Vec3, byref n as Vec3 ) as Vec3

Notes

• v - 2 * Dot( v, n ) * n, which assumes n is already normalised -- it does not normalise for you, because in a renderer it already is and the root would be wasted.
• The mirror-bounce of a ray or a velocity.
• A vector parallel to the normal comes back negated.

Examples

#import "std/numeric"
using numeric

dim as Vec3 v = type<Vec3>( 1, -1, 0 )
dim as Vec3 n = type<Vec3>( 0, 1, 0 )      '' already normalised

dim as Vec3 r = Reflect( v, n )
print r.x & " " & r.y        '' 1 1 -- the y component flipped

'' It does NOT normalise n for you

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Library: Math Library
Category: Math Library
Documented under: Members