the directx docs state:
P = normalize(Plane);
L = Light;
d = dot(P, L)
P.a * L.x + d P.a * L.y P.a * L.z P.a * L.w
P.b * L.x P.b * L.y + d P.b * L.z P.b * L.w
P.c * L.x P.c * L.y P.c * L.z + d P.c * L.w
P.d * L.x P.d * L.y P.d * L.z P.d * L.w + d
I have tried to derive the matrix myself and the closest I got was this:
{
{ld - lpx * pna - pnd, -lpy * pna, -lpz * pna, -pna}
,{-lpx * pnb, ld - lpy * pnb - pnd, -lpz * pnb, -pnb}
,{-lpx * pnc, -lpy * pnc, ld - lpz * pnc - pnd, -pnc}
,{lpx * pnd, lpy * pnd, lpz * pnd, ld}
}
from this equation:
ld = lp . pn
(vp - lp) * ld
vp' = -------------- + lp
ld - (vp . pn)
I derived the reflection matrix in about 2 minutes - I have been working on this shadow matrix for 4 days now :-(
in my test program my matrix works, the dx matrix does not
does anybody know how to derive this matrix - are the directx docs correct?
I keep expecting to have a forehead-slapping moment but its not coming ...
