doom fire text.lua

local fireBlocks = {}
local tilesize = 8
local numberWidthBlocks = math.floor(ScrW() / tilesize)
local numberHeightBlocks = 48 -- means all the 36 colors with a little more space to remaining flames
local offsetY = ScrH() - (numberHeightBlocks * tilesize)

local colorLookup = {
    Color(7,7,7),
	Color(31,7,7),
	Color(47,15,7),
	Color(71,15,7),
	Color(87,23,7),
	Color(103,31,7),
	Color(119,31,7),
	Color(143,39,7),
	Color(159,47,7),
	Color(175,63,7),
	Color(191,71,7),
	Color(199,71,7),
	Color(223,79,7),
	Color(223,87,7),
	Color(223,87,7),
	Color(215,95,7),
	Color(215,95,7),
	Color(215,103,15),
	Color(207,111,15),
	Color(207,119,15),
	Color(207,127,15),
	Color(207,135,23),
	Color(199,135,23),
	Color(199,143,23),
	Color(199,151,31),
	Color(191,159,31),
	Color(191,159,31),
	Color(191,167,39),
	Color(191,167,39),
	Color(191,175,47),
	Color(183,175,47),
	Color(183,183,47),
	Color(183,183,55),
	Color(207,207,111),
	Color(223,223,159),
	Color(239,239,199),
    Color(255,255,25),
}

for i,v in ipairs(colorLookup) do
    v.a = (i/#colorLookup) * 255
end

for line = 1,numberHeightBlocks do
	table.insert(fireBlocks, {})
	
    local yValue = (line - 1) * tilesize + offsetY
    for col = 1,numberWidthBlocks do
		if line < numberHeightBlocks - 1 then
			table.insert(fireBlocks[line], {x = (col-1) * tilesize, y = yValue, color = 1})
		else
			table.insert(fireBlocks[line], {x = (col-1) * tilesize, y = yValue, color = 36})
		end
    end
end

local function draw()
	for line, cols in ipairs(fireBlocks) do
        for _, block in ipairs(cols) do
			surface.SetDrawColor(colorLookup[math.Clamp(math.floor(block.color), 1, #colorLookup)])
			surface.DrawRect(block.x, block.y, tilesize, tilesize)
		end
	end
end

local alphaMap = {}
local tex = GetRenderTarget("doomfire"..math.random(), numberWidthBlocks, numberHeightBlocks) 
print(numberWidthBlocks, numberHeightBlocks)
surface.CreateFont( "FireFont", {
	font = "Arial", -- Use the font-name which is shown to you by your operating system Font Viewer, not the file name
	extended = false,
	size = 50,
	weight = 500,
	blursize = 0,
	scanlines = 0,
	antialias = true,
	underline = false,
	italic = false,
	strikeout = false,
	symbol = false,
	rotary = false,
	shadow = false,
	additive = false,
	outline = false,
} )

surface.DisableClipping(true)
render.PushRenderTarget(tex)
    render.Clear(0,0,0,0)
    cam.Start2D()

    surface.SetFont("FireFont")
    local w, h = surface.GetTextSize("FIRE")

    surface.SetTextPos(numberWidthBlocks/2 - w/2, 5)
    surface.SetTextColor(255,255,255,255)
    surface.DrawText("FIRE")


    cam.End2D()
    render.CapturePixels()

    for x = 0, numberWidthBlocks do
        alphaMap[x] = alphaMap[x] or {}
        for y = 0, numberHeightBlocks do
            alphaMap[x][y] = alphaMap[x][y] or {}
            local r,g,b = render.ReadPixel(x,y)
            r = r / 255
            g = g / 255
            b = b / 255
            local dist = math.sqrt(r*r + g*g + b*b) / 1.78
            alphaMap[x][y] = dist ^0.1
        end
    end
render.PopRenderTarget()
surface.DisableClipping(false)

local nextUpdate = 0

local function update()
    
    if nextUpdate > RealTime() then
        return
    end

    nextUpdate = RealTime() + 1/16

	for line = 1,numberHeightBlocks - 1 do
		for col = 2,numberWidthBlocks - 1 do
			local windDirection = math.random()
            local alpha = alphaMap[col] and alphaMap[col][line] or 0
            local decay = 5

            decay = decay - alpha*6 - math.random()



			local collumn_To_Apply = col
			if windDirection < 0.2 then
				collumn_To_Apply = (col - 1)
			elseif windDirection > 0.8 then
				collumn_To_Apply = (col + 1)
			end
			if fireBlocks[line+1][col].color - decay > 1 then
				fireBlocks[line][collumn_To_Apply].color = fireBlocks[line+1][col].color - decay
			else
				fireBlocks[line][collumn_To_Apply].color = 1
			end
		end
	end
end

local mat = CreateMaterial("firemat" .. math.random(),"UnlitGeneric",{
	["$basetexture"] = "models/shadertest/shader5",
	["$vertexcolor"] = 1,
	["$vertexalpha"] = 1,
})

mat:SetTexture("$basetexture",tex)


hook.Add("HUDPaint", "doom", function() 
    surface.SetDrawColor(255,255,255,255)
    surface.SetMaterial(mat)
    surface.DrawTexturedRect(0,0,tex:Width(), tex:Height())
    draw()
end)
hook.Add("Think", "doom", update)


timer.Remove("doomfire")