Terrain-Point Algorithm

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

Using the function below, how could I find a decent way to generates points, so that when the triangles are draw (using the points as vertices), it would create some terrain?

Code:: local ply = Instance.new("WedgePart")
ply.formFactor = "Custom"
ply.TopSurface = 0
ply.BottomSurface = 0
ply.Anchored = true
ply.Size = Vector3.new(0.2,7,7)

local msh = Instance.new("SpecialMesh")
msh.MeshType = 2
msh.Parent = ply

function ParaD(a, b, c)
local dot = (b-a).x*(c-a).x + (b-a).y*(c-a).y + (b-a).z*(c-a).z
return dot / (a-b).magnitude
end

function PerpD(a, b, c)
local par = ParaD(a, b, c)
return math.sqrt((c-a).magnitude^2 - par^2)
end

local _P0, _P1 = nil, nil

function DrawTriangle(vec1, vec2, vec3)
local A, B, C = nil, nil, nil
local p0, p1 = ply:clone(), ply:clone()
_P0 = p0
_P1 = p1
local s1 = (vec1 - vec2).magnitude
      s2 = (vec2 - vec3).magnitude
      s3 = (vec3 - vec1).magnitude
local smax = math.max(s1, s2, s3)
if (vec1 - vec2).magnitude == smax then
   A = vec1
   B = vec2
   C = vec3
elseif (vec2 - vec3).magnitude == smax then
   A = vec2
   B = vec3
   C = vec1
elseif (vec3 - vec1).magnitude == smax then
   A = vec3
   B = vec1
   C = vec2
end
local perp = PerpD(A, B, C)
local para = ParaD(A, B, C)
local dif_para = (A-B).magnitude - para
local ambig = false
p0.Mesh.Scale = Vector3.new(0.1, 1,1)
p0.Size = Vector3.new(.2, perp, para)
p0.CFrame = CFrame.new(B, A)
local Top_Look = (p0.CFrame * CFrame.fromEulerAnglesXYZ(math.pi/2, 0, 0)).lookVector
local Mid_Point = A + CFrame.new(A, B).lookVector * para
local Needed_Look = CFrame.new(Mid_Point, C).lookVector
local dot = Top_Look.x*Needed_Look.x + Top_Look.y*Needed_Look.y + Top_Look.z*Needed_Look.z
p0.CFrame = p0.CFrame * CFrame.fromEulerAnglesXYZ(0, 0, math.acos(dot))
if ((p0.CFrame * CFrame.fromEulerAnglesXYZ(math.pi/2, 0, 0)).lookVector - Needed_Look).magnitude > 0.01 then
   p0.CFrame = p0.CFrame * CFrame.fromEulerAnglesXYZ(0, 0, -2*math.acos(dot))
   ambig = true
end
p0.CFrame = p0.CFrame * CFrame.new(0, perp/2, -(dif_para + para/2))
p0.Parent = tmodel
p0.Name = "P0"
p1.Mesh.Scale = Vector3.new(0, 1,1)
p1.Size = Vector3.new(.2, perp, dif_para)
p1.CFrame = CFrame.new(B, A) * CFrame.fromEulerAnglesXYZ(0, 0, math.acos(dot)) * CFrame.fromEulerAnglesXYZ(0, math.pi, 0)
if ((p1.CFrame * CFrame.fromEulerAnglesXYZ(math.pi/2, 0, 0)).lookVector - Needed_Look).magnitude > 0.01 then
   p1.CFrame = p1.CFrame * CFrame.fromEulerAnglesXYZ(0, 0, 2*math.acos(dot))
   ambig = true
end
p1.CFrame = p1.CFrame * CFrame.new(0, perp/2, dif_para/2)
p1.Parent = tmodel
p1.Name = "P1"
--p0.Mesh.Scale = p0.Mesh.Scale * 0.145714286
--p1.Mesh.Scale = p1.Mesh.Scale * 0.145714286
end

Administrator Posts : 878 Join date : 2010-07-30

I'm not sure. How would you make a triangle in the first place with pieces?

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

I already have them made. There is a function in the code to do so.

Administrator Posts : 878 Join date : 2010-07-30

Great, now you made me want to go mess with the triangle.

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

It's quite entertaining, I've made a tool and a place that uses them together to build while online.

Administrator Posts : 878 Join date : 2010-07-30

So, what your trying to do is make the triangle big enough to fill the drawn triangle?

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

No no, that is all done. I just want to generate points so I can draw the triangles to look like mountains or something.

Administrator Posts : 878 Join date : 2010-07-30

I know somebody made something like that, just I don't think it was with triangles and it was just a randomized terrain.

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

A lot of people made random terrain, xLEGOx did a random terrain with triangles (the main way to make decent terrain).

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

maybe have the points generate randomly as long as it's within a certain height to the lowest and highest points adjacent to the point.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

I was thinking of making one of these map generators myself!

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

Sorry, but that didn't make any sense at all.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

every time you generate a point you make it generate at a random height in-between the lowest and highest points next to the point. make more sense?

Guest

Yeah Blue's way is rather efficient. I use it in my terrain generator, although since mine is row-based rather than 2D-based, it isn't as good as it could be.

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

blueymaddog wrote:: every time you generate a point you make it generate at a random height in-between the lowest and highest points next to the point. make more sense?

You obviously don't understand an algorithm that should be used here. I figured it should be the Diamond-Square algorithm for random triangle-based terrain. I decided to ask the Scripters on Roblox. Interesting results are being turned up.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

link to thread please, MNN?

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

Here is the link.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

lol, so your asking me how you should generate the points on the terrain generater and I give my suggestion. then you say that you should use the 'diamond-square' algorithm. :P

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

An algorithm is a solution, your "algorithim" was no where near a solution to keep the terrain smooth and actually look like terrain.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

then get the average of all the point's positions and make it randomize roughly around the average. :P

Expert Scripter Posts : 27 Join date : 2011-03-06 Age : 28

I already have a solution.

Administrator Posts : 1081 Join date : 2010-12-09 Age : 26

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Terrain-Point Algorithm

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