boatbomber / ViewportCanvas

A greedy meshed canvas for arbitrary drawings on Roblox

ViewportCanvas

A canvas renderer using greedy meshed parts in a ViewportFrame to draw efficiently in Roblox. Serves as an alternative to GradientCanvas since that one hits Roblox's UI cap.

Here's ViewportCanvas rendering a 4k image (that's 8,294,400 pixels!) using just 1,176,336 Parts. No UI cap to concern yourself with!

API

ViewportCanvas.new(ResolutionX: number, ResolutionY: number)

returns a new canvas of the specified resolution

ViewportCanvas.Threshold: number

Defines the greediness of the mesher using CIE76 color distances, should stay between 1 and 30

ViewportCanvas:SetParent(Parent: Instance)

parents the canvas GUI to the passed Instance

ViewportCanvas:SetPixel(X: number, Y: number, Color: Color3)

Sets the color of the canvas specified pixel

ViewportCanvas:Render()

renders the canvas based on the set pixels

(It will not automatically render, you must call this method when you've completed your pixel updates)

ViewportCanvas:Clear()

clears the canvas render

ViewportCanvas:Destroy()

cleans up the canvas and its GUIs

---

Demonstration

-- Frames
local Demo = script.Parent.Demo
local Ref = script.Parent.Ref

-- Resolution
local ResX, ResY = 16*10, 9*10

-- Create Canvas
local Canvas = require(script.ViewportCanvas).new(ResX, ResY)
Canvas:SetParent(Demo.Holder)

-- Draw pixels
for x=1, ResX do
	for y=1, ResY do
		-- Define color
		local color = Color3.fromHSV(x/ResX, y/ResY, 1)

		-- Set in canvas
		Canvas:SetPixel(x, y, color)

		-- Draw naively for reference
		local pixel = Instance.new("Frame")
		pixel.BorderSizePixel = 0
		pixel.BackgroundColor3 = color
		pixel.Size = UDim2.fromScale(1/ResX, 1/ResY)
		pixel.Position = UDim2.fromScale((1/ResX)*(x-1), (1/ResY)*(y-1))
		pixel.Parent = Ref.Holder
	end
end

-- Render canvas
Canvas:Render()

-- Expose counts
Demo.Info.Text = string.format("%d Part instances (%.1f%% improvement!)", Canvas._ActiveParts, ((ResX*ResY)-Canvas._ActiveParts)/(ResX*ResY)*100)
Ref.Info.Text = string.format("Frames Instances: %d", ResX*ResY)