Oh shadows… I’ve made a system that that can raycast and build up a shadow out of tris.
As a performance optimisation I’ve relied on not raycasting thousands of times to build up an image, this is how the system is built up to allow for real time shadows:
- Get the vertices of the cube, that means we raycast 8 times
- After that depending on where all raycasts hit the script builds up a “2D” shape that represents the shadow out of tris (tris being a polygon made up of 3 vectors basically being a 3D triangle)
After that we get this decently good result:
Oh noes! There’s a complicated bug!
This is pretty self explanatory what’s causing this but the problem lies in the whole system itself, I need guidance of how I could solve the issue. To solve this I’m going to have to be subdividing triangles which is not something I have much of experience on, also that somehow I need to make an algorithm that finds the places to “cut” the triangles at maybe even at multiple places!
Code
local CubeShadowPositions = {Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero} --
local Wedges = {}
local wedge = Instance.new("WedgePart");
wedge.Anchored = true;
wedge.Color = Color3.new(0.231006, 0.231815, 0.234257)
wedge.TopSurface = Enum.SurfaceType.Smooth;
wedge.BottomSurface = Enum.SurfaceType.Smooth;
wedge.Material = Enum.Material.Neon
wedge.CanCollide = false
wedge.CanTouch = false
wedge.CanQuery = false
local rot = Vector3.new()
local function draw3dTriangle(a, b, c, parent)
local ab, ac, bc = b - a, c - a, c - b;
local abd, acd, bcd = ab:Dot(ab), ac:Dot(ac), bc:Dot(bc);
if (abd > acd and abd > bcd) then
c, a = a, c;
elseif (acd > bcd and acd > abd) then
a, b = b, a;
end
ab, ac, bc = b - a, c - a, c - b;
local right = ac:Cross(ab).unit;
local up = bc:Cross(right).unit;
local back = bc.unit;
local height = math.abs(ab:Dot(up));
local w1 = wedge:Clone();
w1.Size = Vector3.new(0, height, math.abs(ab:Dot(back)));
w1.CFrame = CFrame.fromMatrix((a + b)/2, right, up, back);
w1.Parent = parent;
local w2 = wedge:Clone();
w2.Size = Vector3.new(0, height, math.abs(ac:Dot(back)));
w2.CFrame = CFrame.fromMatrix((a + c)/2, -right, up, -back);
w2.Parent = parent;
table.insert(Wedges, w1)
table.insert(Wedges, w2)
return w1, w2;
end
game:GetService("RunService").Heartbeat:Connect(function()
for i = 1, #Wedges do
Wedges[i]:Destroy()
end
table.clear(Wedges)
for i,v in pairs(game.Workspace:GetDescendants()) do
if v:IsA("BasePart") then
--print(v.Name, v.Position)
CubeShadowPositions = {Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero,Vector3.zero}
local rayparams = RaycastParams.new()
rayparams.FilterType = Enum.RaycastFilterType.Exclude
rayparams.FilterDescendantsInstances = {v}
if v.Parent:IsA("Model") then
rayparams.FilterDescendantsInstances = {v.Parent:GetDescendants()}
elseif v.Parent:IsA("Accessory") then
rayparams.FilterDescendantsInstances = {v.Parent.Parent:GetDescendants()}
end
local ray = game.Workspace:Raycast((v.CFrame * CFrame.new(v.Size.X/2, v.Size.Y/2, v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray then
CubeShadowPositions[5] = ray.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(-v.Size.X/2, v.Size.Y/2, v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[6] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(v.Size.X/2, -v.Size.Y/2, v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[7] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(v.Size.X/2, v.Size.Y/2, -v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[1] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(-v.Size.X/2, -v.Size.Y/2, v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[8] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(v.Size.X/2, -v.Size.Y/2, -v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[2] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(-v.Size.X/2, v.Size.Y/2, -v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[3] = ray2.Position
end
local ray2 = game.Workspace:Raycast((v.CFrame * CFrame.new(-v.Size.X/2, -v.Size.Y/2, -v.Size.Z/2)).Position + game.Lighting:GetSunDirection().Unit*1, -game.Lighting:GetSunDirection().Unit*60,rayparams)
if ray2 then
CubeShadowPositions[4] = ray2.Position
end
if CubeShadowPositions[1].X == 0 and CubeShadowPositions[2].X == 0 and CubeShadowPositions[3].X == 0 and CubeShadowPositions[4].X == 0 and CubeShadowPositions[5].X == 0 and CubeShadowPositions[6].X == 0 and CubeShadowPositions[7].X == 0 and CubeShadowPositions[8].X == 0 then
else
draw3dTriangle(CubeShadowPositions[1],CubeShadowPositions[2],CubeShadowPositions[3], v)
draw3dTriangle(CubeShadowPositions[4],CubeShadowPositions[2],CubeShadowPositions[3], v)
draw3dTriangle(CubeShadowPositions[5],CubeShadowPositions[6],CubeShadowPositions[7], v)
draw3dTriangle(CubeShadowPositions[8],CubeShadowPositions[6],CubeShadowPositions[7], v)
draw3dTriangle(CubeShadowPositions[1],CubeShadowPositions[2],CubeShadowPositions[5], v)
draw3dTriangle(CubeShadowPositions[7],CubeShadowPositions[2],CubeShadowPositions[5], v)
draw3dTriangle(CubeShadowPositions[4],CubeShadowPositions[3],CubeShadowPositions[8], v)
draw3dTriangle(CubeShadowPositions[6],CubeShadowPositions[3],CubeShadowPositions[8], v)
draw3dTriangle(CubeShadowPositions[4],CubeShadowPositions[2],CubeShadowPositions[8], v)
draw3dTriangle(CubeShadowPositions[7],CubeShadowPositions[2],CubeShadowPositions[8], v)
draw3dTriangle(CubeShadowPositions[3],CubeShadowPositions[1],CubeShadowPositions[6], v)
draw3dTriangle(CubeShadowPositions[5],CubeShadowPositions[1],CubeShadowPositions[6], v)
end
end
end
end)
How could I go about making this algorithm? Plus to not crash the players pc?
edit: If there is a better and more lag efficient way of doing this please inform me about that : )
