JurassicParkTrespasser/jp2_pc/Tools/MAXScript/IntersectRay.ms
2018-01-01 23:07:24 +01:00

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fn MaxComp N =
(
m = (abs N.x)
i = 1
if (abs N.y) > m do
(
m = (abs N.y)
i = 2
)
if (abs N.z) > m do
(
m = (abs N.z)
i = 3
)
return i
)
fn Intersect r oMesh =
(
local nf = oMesh.numfaces
local debug = false
local rPoint, rNormal, rIndex, rUV
-- first get t (where t > 0) for all faces in the object
TmpArray = #()
TmpIndices = #()
TArray = #()
TIndices = #()
for i = 1 to nf do
(
-- get the vertex indices of the current face
CFace = getFace oMesh i
-- get the vertex positions of the vace
V0 = (getVert oMesh CFace.x)
-- get the normal of the face
N = getFaceNormal oMesh i
d = -(dot V0 N)
t = -((d + (dot N r.pos)) / (dot N r.dir))
if t > 0.0 do
(
append TmpArray t
append TmpIndices i
)
)
if TmpArray.count != 0 do
(
aTemp = (SortUp2 TmpArray TmpIndices)
TArray = aTemp[1]
TIndices = aTemp[2]
for i = 1 to TIndices.count do
(
t = TArray[i]
if debug do format "\n\nFace:%\n" TIndices[i]
-- get the vertex indices of the current face
CFace = getFace oMesh TIndices[i]
-- get the vertex positions of the vace
V0 = (getVert oMesh CFace.x)
V0 = #(V0.x, V0.y, V0.z)
V1 = (getVert oMesh CFace.y)
V1 = #(V1.x, V1.y, V1.z)
V2 = (getVert oMesh CFace.z)
V2 = #(V2.x, V2.y, V2.z)
local V = #(V0, V1, V2)
-- First Rejection test (t>0)
if t > 0.0 then
(
N = getFaceNormal oMesh TIndices[i]
-- second rejection test, are the normals parallel?
if (dot N r.dir) != 0 do
(
inter = false
P0 = r.pos.x + r.dir.x * t
P1 = r.pos.y + r.dir.y * t
P2 = r.pos.z + r.dir.z * t
P = #(P0, P1, P2)
if debug do
(
format "Intersection Point = %\n" [p0,p1,p2]
s = sphere()
s.radius = .25
s.pos = [p0,p1,p2]
)
-- determine the max component of N
i0 = MaxComp N
if debug do format "Maximum component:%\n" i0
if i0 == 1 do (i1 = 2;i2 = 3)
if i0 == 2 do (i1 = 3;i2 = 1)
if i0 == 3 do (i1 = 1;i2 = 2)
u0 = P[i1] - V[1][i1]
v0 = P[i2] - V[1][i2]
u1 = V[2][i1] - V[1][i1]
u2 = V[3][i1] - V[1][i1]
v1 = V[2][i2] - V[1][i2]
v2 = V[3][i2] - V[1][i2]
if debug do format "u0:%\t\tu1:%\t\tu2:%\nv0:%\t\tv1:%\t\tv2:%\n" u0 u1 u2 v0 v1 v2
if u1 == 0 then
(
beta = u0/u2 as float
if debug do format "beta:%\n" beta
if (beta >= 0.0) and (beta <= 1.0) do
(
alpha = (v0 - beta * v2) / v1
if debug do format "alpha:%\n" alpha
inter = ((alpha >= 0) and ((alpha + beta) <=1))
)
) else (
beta = ((v0 * u1) - (u0 * v1)) / ((v2 * u1) - (u2 * v1))
if debug do format "Beta:%\n" beta
if ((beta >= 0.0) and (beta <= 1.0)) do
(
alpha = (u0 - (beta * u2)) / u1
if debug do format "Alpha:%\n" alpha
if (inter = ((alpha >= 0) and ((alpha + beta) <=1))) do
(
CTVFace = getTVFace oMesh TIndices[i]
-- get the TVerts of the face
tv0 = (getTVert oMesh CTVFace.x)
tv1 = (getTVert oMesh CTVFace.y)
tv2 = (getTVert oMesh CTVFace.z)
local tv = #(tv0, tv1, tv2)
rUV = ((tv0 * (1 - (alpha + beta))) + (tv1 * alpha) + (tv2 * beta))
rPoint = P
-- get the normal of the face
rN = N
rIndex = TIndices[i]
return #(rPoint, rN, rIndex, rUV)
)
)
)
)
)
)
)
return undefined
)
-- returns the magnitude of a vector
fn MagV vec = (sqrt((vec.x)^2 + (vec.y)^2 + (vec.z)^2))
-- returns a normalized vector between two objects
fn GetNormalDirVec o1 o2 = normalize (o2.pos - o1.pos)
-- returns a non-normalized vector between two objects
fn GetDirVec o1 o2 = (o2.pos - o1.pos)
-- returns a ray from one object to another
fn CreateRay o1 o2 =
return (ray o1.pos (GetNormalDirVec o2 o1))