VertexGraphics module (ROBLOX)

-- By noliCAIKS/RPFeltz, somewhere in 2014

local VertexGraphics = {}
local vertexColor = BrickColor.new(Color3.new(0, 0, 0))
local vertexFixed = true
local vertexLocked = true
local vertexMaterial = Enum.Material.Plastic
local vertexSolid = false
local vertexTransparency = 0
local vertexTriangleOffset = 0

local function GenerateStockPart(className)
    local stockPart = Instance.new(className)
    stockPart.Anchored = vertexFixed
    stockPart.BackSurface = "SmoothNoOutlines"
    stockPart.BottomSurface = "SmoothNoOutlines"
    stockPart.BrickColor = vertexColor
    stockPart.CanCollide = vertexSolid
    stockPart.FormFactor = "Custom"
    stockPart.FrontSurface = "SmoothNoOutlines"
    stockPart.LeftSurface = "SmoothNoOutlines"
    stockPart.Locked = vertexLocked
    stockPart.Material = vertexMaterial
    stockPart.RightSurface = "SmoothNoOutlines"
    stockPart.TopSurface = "SmoothNoOutlines"
    stockPart.Transparency = vertexTransparency
    return stockPart
end

function VertexGraphics.drawLineFan(vertices, parent, thickness)
    thickness = thickness or 0.2
    local stockPart = GenerateStockPart("Part")
    local count = #vertices
    local previous = nil
    local vertex1, vertex2 = vertices[1], nil
    for index = 2, count do
        vertex2 = vertices[index]
        local offset = vertex2 - vertex1
        local distance = offset.magnitude
        local center = vertex1:Lerp(vertex2, 0.5)
        local part = stockPart:Clone()
        local mesh = Instance.new("CylinderMesh", part)
        local size = Vector3.new(thickness, distance, thickness)
        part.CFrame = CFrame.new(center, vertex2) * CFrame.new(0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1, 0)
        part.Size = size
        mesh.Scale = size / part.Size
        if not vertexFixed and previous then
            JoinParts(previous, part)
        end
        previous = part
        part.Parent = parent
    end
    parent.PrimaryPart = previous
end
function VertexGraphics.drawLineStrip(vertices, parent, thickness)
    thickness = thickness or 0.2
    local stockPart = GenerateStockPart("Part")
    local count = #vertices
    local previous = nil
    local vertex1, vertex2 = nil, vertices[1]
    for index = 2, count do
        vertex1, vertex2 = vertex2, vertices[index]
        local offset = vertex2 - vertex1
        local distance = offset.magnitude
        local center = vertex1:Lerp(vertex2, 0.5)
        local part = stockPart:Clone()
        local mesh = Instance.new("CylinderMesh", part)
        local size = Vector3.new(thickness, distance, thickness)
        part.CFrame = CFrame.new(center, vertex2) * CFrame.new(0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1, 0)
        part.Size = size
        mesh.Scale = size / part.Size
        if not vertexFixed and previous then
            JoinParts(previous, part)
        end
        previous = part
        part.Parent = parent
    end
    parent.PrimaryPart = previous
end
function VertexGraphics.drawTriangleFan(vertices, parent, thickness)
    thickness = thickness or 0
    local stockPart = GenerateStockPart("WedgePart")
    local count = #vertices
    local previous = nil
    local vertexIterator1, vertexIterator2, vertexIterator3 = vertices[1], nil, vertices[2]
    local offsetIterator1, offsetIterator2, offsetIterator3 = nil, nil, vertexIterator1 - vertexIterator3
    local dotIterator1, dotIterator2, dotIterator3 = nil, nil, offsetIterator3:Dot(offsetIterator3)
    for index = 3, count do
        vertexIterator2, vertexIterator3 = vertexIterator3, vertices[index]
        offsetIterator1, offsetIterator2, offsetIterator3 = -offsetIterator3, vertexIterator3 - vertexIterator2, vertexIterator1 - vertexIterator3
        dotIterator1, dotIterator2, dotIterator3 = dotIterator3, offsetIterator2:Dot(offsetIterator2), offsetIterator3:Dot(offsetIterator3)
        local vertex1, vertex2, vertex3
        local offset1, offset2, offset3
        local dot1, dot2, dot3
        if dotIterator1 > dotIterator2 then
            if dotIterator1 > dotIterator3 then
                vertex1, vertex2, vertex3 = vertexIterator1, vertexIterator2, vertexIterator3
                offset1, offset2, offset3 = offsetIterator1, offsetIterator2, offsetIterator3
                dot1, dot2, dot3 = dotIterator1, dotIterator2, dotIterator3
            else
                vertex1, vertex2, vertex3 = vertexIterator3, vertexIterator1, vertexIterator2
                offset1, offset2, offset3 = offsetIterator3, offsetIterator1, offsetIterator2
                dot1, dot2, dot3 = dotIterator3, dotIterator1, dotIterator2
            end
        elseif dotIterator2 > dotIterator3 then
            vertex1, vertex2, vertex3 = vertexIterator2, vertexIterator3, vertexIterator1
            offset1, offset2, offset3 = offsetIterator2, offsetIterator3, offsetIterator1
            dot1, dot2, dot3 = dotIterator2, dotIterator3, dotIterator1
        else
            vertex1, vertex2, vertex3 = vertexIterator3, vertexIterator1, vertexIterator2
            offset1, offset2, offset3 = offsetIterator3, offsetIterator1, offsetIterator2
            dot1, dot2, dot3 = dotIterator3, dotIterator1, dotIterator2
        end
        local length1 = math.sqrt(dot1)
        local distanceMiddle = (dot1 + dot3 - dot2) / (2 * length1)
        local offsetMiddle = vertex1:Lerp(vertex2, distanceMiddle / length1)
        local offsetTop = vertex3 - offsetMiddle
        local height = offsetTop.magnitude
        local axisY, axisZ = offsetTop / height, offset1 / length1
        local axisX = axisY:Cross(axisZ)
        local size1, size2 = Vector3.new(thickness, height, distanceMiddle), Vector3.new(thickness, height, length1 - distanceMiddle)
        local part1, part2 = stockPart:Clone(), stockPart:Clone()
        part1.CFrame = CFrame.new(offsetMiddle.X, offsetMiddle.Y, offsetMiddle.Z, axisX.X, axisY.X, axisZ.X, axisX.Y, axisY.Y, axisZ.Y, axisX.Z, axisY.Z, axisZ.Z) * CFrame.new(-vertexTriangleOffset, height * 0.5, distanceMiddle * -0.5)
        part2.CFrame = CFrame.new(offsetMiddle.X, offsetMiddle.Y, offsetMiddle.Z, -axisX.X, axisY.X, -axisZ.X, -axisX.Y, axisY.Y, -axisZ.Y, -axisX.Z, axisY.Z, -axisZ.Z) * CFrame.new(vertexTriangleOffset, height * 0.5, (distanceMiddle - length1) * 0.5)
        part1.Size = size1
        part2.Size = size2
        local realSize1, realSize2 = part1.Size, part2.Size
        if size1 ~= realSize1 or size2 ~= realSize2 then
            local mesh1 = Instance.new("SpecialMesh")
            mesh1.MeshType = "Wedge"
            local mesh2 = mesh1:Clone()
            mesh1.Scale = size1 / realSize1
            mesh2.Scale = size2 / realSize2
            mesh1.Parent = part1
            mesh2.Parent = part2
        end
        if not vertexFixed then
            VertexGraphics.joinParts(part1, part2)
            if previous then
                VertexGraphics.joinParts(previous, part1)
            end
        end
        previous = part1
        part1.Parent = parent
        part2.Parent = parent
    end
    parent.PrimaryPart = previous
end
function VertexGraphics.drawTriangleStrip(vertices, parent, thickness)
    thickness = thickness or 0
    local offsetMultiplier = 1
    local stockPart = GenerateStockPart("WedgePart")
    local count = #vertices
    local previous = nil
    local vertexIterator1, vertexIterator2, vertexIterator3 = nil, vertices[1], vertices[2]
    local offsetIterator1, offsetIterator2, offsetIterator3 = nil, vertexIterator3 - vertexIterator2, nil
    local dotIterator1, dotIterator2, dotIterator3 = nil, offsetIterator2:Dot(offsetIterator2), nil
    for index = 3, count do
        vertexIterator1, vertexIterator2, vertexIterator3 = vertexIterator2, vertexIterator3, vertices[index]
        offsetIterator1, offsetIterator2, offsetIterator3 = offsetIterator2, vertexIterator3 - vertexIterator2, vertexIterator1 - vertexIterator3
        dotIterator1, dotIterator2, dotIterator3 = dotIterator2, offsetIterator2:Dot(offsetIterator2), offsetIterator3:Dot(offsetIterator3)
        local vertex1, vertex2, vertex3
        local offset1, offset2, offset3
        local dot1, dot2, dot3
        if dotIterator1 > dotIterator2 then
            if dotIterator1 > dotIterator3 then
                vertex1, vertex2, vertex3 = vertexIterator1, vertexIterator2, vertexIterator3
                offset1, offset2, offset3 = offsetIterator1, offsetIterator2, offsetIterator3
                dot1, dot2, dot3 = dotIterator1, dotIterator2, dotIterator3
            else
                vertex1, vertex2, vertex3 = vertexIterator3, vertexIterator1, vertexIterator2
                offset1, offset2, offset3 = offsetIterator3, offsetIterator1, offsetIterator2
                dot1, dot2, dot3 = dotIterator3, dotIterator1, dotIterator2
            end
        elseif dotIterator2 > dotIterator3 then
            vertex1, vertex2, vertex3 = vertexIterator2, vertexIterator3, vertexIterator1
            offset1, offset2, offset3 = offsetIterator2, offsetIterator3, offsetIterator1
            dot1, dot2, dot3 = dotIterator2, dotIterator3, dotIterator1
        else
            vertex1, vertex2, vertex3 = vertexIterator3, vertexIterator1, vertexIterator2
            offset1, offset2, offset3 = offsetIterator3, offsetIterator1, offsetIterator2
            dot1, dot2, dot3 = dotIterator3, dotIterator1, dotIterator2
        end
        local length1 = math.sqrt(dot1)
        local distanceMiddle = (dot1 + dot3 - dot2) / (2 * length1)
        local offsetMiddle = vertex1:Lerp(vertex2, distanceMiddle / length1)
        local offsetTop = vertex3 - offsetMiddle
        local height = offsetTop.magnitude
        local axisY, axisZ = offsetTop / height, offset1 / length1
        local axisX = axisY:Cross(axisZ)
        local size1, size2 = Vector3.new(thickness, height, distanceMiddle), Vector3.new(thickness, height, length1 - distanceMiddle)
        local part1, part2 = stockPart:Clone(), stockPart:Clone()
        part1.CFrame = CFrame.new(offsetMiddle.X, offsetMiddle.Y, offsetMiddle.Z, axisX.X, axisY.X, axisZ.X, axisX.Y, axisY.Y, axisZ.Y, axisX.Z, axisY.Z, axisZ.Z) * CFrame.new(offsetMultiplier * -vertexTriangleOffset, height * 0.5, distanceMiddle * -0.5)
        part2.CFrame = CFrame.new(offsetMiddle.X, offsetMiddle.Y, offsetMiddle.Z, -axisX.X, axisY.X, -axisZ.X, -axisX.Y, axisY.Y, -axisZ.Y, -axisX.Z, axisY.Z, -axisZ.Z) * CFrame.new(offsetMultiplier * vertexTriangleOffset, height * 0.5, (distanceMiddle - length1) * 0.5)
        part1.Size = size1
        part2.Size = size2
        local realSize1, realSize2 = part1.Size, part2.Size
        if size1 ~= realSize1 or size2 ~= realSize2 then
            local mesh1 = Instance.new("SpecialMesh")
            mesh1.MeshType = "Wedge"
            mesh1.Name = "Mesh"
            local mesh2 = mesh1:Clone()
            mesh1.Scale = size1 / realSize1
            mesh2.Scale = size2 / realSize2
            mesh1.Parent = part1
            mesh2.Parent = part2
        end
        if not vertexFixed then
            VertexGraphics.joinParts(part1, part2)
            if previous then
                VertexGraphics.joinParts(previous, part1)
            end
        end
        previous = part1
        part1.Parent = parent
        part2.Parent = parent
        offsetMultiplier = -offsetMultiplier
    end
    parent.PrimaryPart = previous
end
function VertexGraphics.joinModels(model1, model2)
    VertexGraphics.joinParts(model1.PrimaryPart, model2.PrimaryPart)
end
function VertexGraphics.joinParts(part0, part1)
    local weld = Instance.new("Weld", part0)
    weld.Part0 = part0
    weld.Part1 = part1
    weld.C0 = part0.CFrame:inverse()
    weld.C1 = part1.CFrame:inverse()
end

function VertexGraphics.setAlpha(alpha)
    vertexTransparency = 1 - alpha
end
function VertexGraphics.setColor(color)
    vertexColor = color
end
function VertexGraphics.setFixed(fixed)
    vertexFixed = fixed
end
function VertexGraphics.setLocked(locked)
    vertexLocked = locked
end
function VertexGraphics.setMaterial(material)
    vertexMaterial = material
end
function VertexGraphics.setSolid(solid)
    vertexSolid = solid
end
function VertexGraphics.setTriangleOffset(triangleOffset)
    vertexTriangleOffset = triangleOffset
end

return VertexGraphics