luau/bench/tests/mesh-normal-scalar.lua

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2023-05-12 13:15:01 +01:00
--!strict
local bench = script and require(script.Parent.bench_support) or require("bench_support")
function test()
type Vertex = {
pX: number, pY: number, pZ: number,
uvX: number, uvY: number, uvZ: number,
nX: number, nY: number, nZ: number,
tX: number, tY: number, tZ: number,
bX: number, bY: number, bZ: number,
h: number
}
local grid_size = 100
local mesh: {
vertices: {Vertex},
indices: {number},
triangle_cone_p: {{x: number, y: number, z: number}},
triangle_cone_n: {{x: number, y: number, z: number}}
} = {
vertices = table.create(grid_size * grid_size),
indices = table.create((grid_size - 1) * (grid_size - 1) * 6),
triangle_cone_p = table.create((grid_size - 1) * (grid_size - 1) * 2),
triangle_cone_n = table.create((grid_size - 1) * (grid_size - 1) * 2)
}
local function init_vertices()
local i = 1
for y = 1,grid_size do
for x = 1,grid_size do
local v: Vertex = {}
v.pX = x
v.pY = y
v.pZ = math.cos(x) + math.sin(y)
v.uvX = (x-1)/(grid_size-1)
v.uvY = (y-1)/(grid_size-1)
v.uvZ = 0
v.nX = 0
v.nY = 0
v.nZ = 0
v.bX = 0
v.bY = 0
v.bZ = 0
v.tX = 0
v.tY = 0
v.tZ = 0
v.h = 0
mesh.vertices[i] = v
i += 1
end
end
end
local function init_indices()
local i = 1
for y = 1,grid_size-1 do
for x = 1,grid_size-1 do
mesh.indices[i] = x + (y-1)*grid_size
i += 1
mesh.indices[i] = x + y*grid_size
i += 1
mesh.indices[i] = (x+1) + (y-1)*grid_size
i += 1
mesh.indices[i] = (x+1) + (y-1)*grid_size
i += 1
mesh.indices[i] = x + y*grid_size
i += 1
mesh.indices[i] = (x+1) + y*grid_size
i += 1
end
end
end
local function calculate_normals()
local norm_sum = 0
for i = 1,#mesh.indices,3 do
local a = mesh.vertices[mesh.indices[i]]
local b = mesh.vertices[mesh.indices[i + 1]]
local c = mesh.vertices[mesh.indices[i + 2]]
local abx = a.pX - b.pX
local aby = a.pY - b.pY
local abz = a.pZ - b.pZ
local acx = a.pX - c.pX
local acy = a.pY - c.pY
local acz = a.pZ - c.pZ
local nx = aby * acz - abz * acy;
local ny = abz * acx - abx * acz;
local nz = abx * acy - aby * acx;
a.nX += nx
a.nY += ny
a.nZ += nz
b.nX += nx
b.nY += ny
b.nZ += nz
c.nX += nx
c.nY += ny
c.nZ += nz
end
for _,v in mesh.vertices do
local magnitude = math.sqrt(v.nX * v.nX + v.nY * v.nY + v.nZ * v.nZ)
v.nX /= magnitude
v.nY /= magnitude
v.nZ /= magnitude
norm_sum += v.nX * v.nX + v.nY * v.nY + v.nZ * v.nZ
end
return norm_sum
end
local function compute_triangle_cones()
local mesh_area = 0
local pos = 1
for i = 1,#mesh.indices,3 do
local p0 = mesh.vertices[mesh.indices[i]]
local p1 = mesh.vertices[mesh.indices[i + 1]]
local p2 = mesh.vertices[mesh.indices[i + 2]]
local p10x = p1.pX - p0.pX
local p10y = p1.pY - p0.pY
local p10z = p1.pZ - p0.pZ
local p20x = p2.pX - p0.pX
local p20y = p2.pY - p0.pY
local p20z = p2.pZ - p0.pZ
local normalx = p10y * p20z - p10z * p20y;
local normaly = p10z * p20x - p10x * p20z;
local normalz = p10x * p20y - p10y * p20x;
local area = math.sqrt(normalx * normalx + normaly * normaly + normalz * normalz)
local invarea = if area == 0 then 0 else 1 / area;
local rx = (p0.pX + p1.pX + p2.pX) / 3
local ry = (p0.pY + p1.pY + p2.pY) / 3
local rz = (p0.pZ + p1.pZ + p2.pZ) / 3
mesh.triangle_cone_p[pos] = { x = rx, y = ry, z = rz }
mesh.triangle_cone_n[pos] = { x = normalx * invarea, y = normaly * invarea, z = normalz * invarea}
pos += 1
mesh_area += area
end
return mesh_area
end
local function compute_tangent_space()
local checksum = 0
for i = 1,#mesh.indices,3 do
local a = mesh.vertices[mesh.indices[i]]
local b = mesh.vertices[mesh.indices[i + 1]]
local c = mesh.vertices[mesh.indices[i + 2]]
local x1 = b.pX - a.pX
local x2 = c.pX - a.pX
local y1 = b.pY - a.pY
local y2 = c.pY - a.pY
local z1 = b.pZ - a.pZ
local z2 = c.pZ - a.pZ
local s1 = b.uvX - a.uvX
local s2 = c.uvX - a.uvX
local t1 = b.uvY - a.uvY
local t2 = c.uvY - a.uvY
local r = 1.0 / (s1 * t2 - s2 * t1);
local sdirX = (t2 * x1 - t1 * x2) * r
local sdirY = (t2 * y1 - t1 * y2) * r
local sdirZ = (t2 * z1 - t1 * z2) * r
local tdirX = (s1 * x2 - s2 * x1) * r
local tdirY = (s1 * y2 - s2 * y1) * r
local tdirZ = (s1 * z2 - s2 * z1) * r
a.tX += sdirX
a.tY += sdirY
a.tZ += sdirZ
b.tX += sdirX
b.tY += sdirY
b.tZ += sdirZ
c.tX += sdirX
c.tY += sdirY
c.tZ += sdirZ
a.bX += tdirX
a.bY += tdirY
a.bZ += tdirZ
b.bX += tdirX
b.bY += tdirY
b.bZ += tdirZ
c.bX += tdirX
c.bY += tdirY
c.bZ += tdirZ
end
for _,v in mesh.vertices do
local tX = v.tX
local tY = v.tY
local tZ = v.tZ
-- Gram-Schmidt orthogonalize
local ndt = v.nX * tX + v.nY * tY + v.nZ * tZ
local tmnsX = tX - v.nX * ndt
local tmnsY = tY - v.nY * ndt
local tmnsZ = tZ - v.nZ * ndt
local l = math.sqrt(tmnsX * tmnsX + tmnsY * tmnsY + tmnsZ * tmnsZ)
local invl = 1 / l
v.tX = tmnsX * invl
v.tY = tmnsY * invl
v.tZ = tmnsZ * invl
local normalx = v.nY * tZ - v.nZ * tY;
local normaly = v.nZ * tX - v.nX * tZ;
local normalz = v.nX * tY - v.nY * tX;
local ht = normalx * v.bX + normaly * v.bY + normalz * v.bZ
v.h = ht < 0 and -1 or 1
checksum += v.tX + v.h
end
return checksum
end
init_vertices()
init_indices()
calculate_normals()
compute_triangle_cones()
compute_tangent_space()
end
bench.runCode(test, "mesh-normal-scalar")