jprof-churn.lua

--baseline vs churn "try it yourself" love demonstration

--byo jprof
PROF_CAPTURE = true
local prof = require("jprof")

--starting parameters
local churn = 1e3
local baseline = 1e5
local baseline_change_per_frame = 1e3

--build keybinds up
local keybinds_in_order = {
	{"up", "increase churn", function()
		churn = churn * 10
	end},
	{"down", "decrease churn", function()
		churn = churn / 10
	end},
	{"left", "decrease baseline", function()
		baseline = baseline / 10
	end},
	{"right", "increase baseline", function()
		baseline = baseline * 10
	end},
}
local keybinds_map = {}
for i,v in ipairs(keybinds_in_order) do
	keybinds_map[v[1]] = v[3]
end

--maintain the working set
local working_set = {}
local function maintain_baseline()
	for i = 1, baseline_change_per_frame do
		if #working_set < baseline then
			table.insert(working_set, {#working_set})
		end
		if #working_set > baseline then
			table.remove(working_set)
		end
	end
end

--on load, connect to jprof and set up the baseline
function love.load()
	print(prof, prof.connect(false))
	maintain_baseline()
end

--storage for the per-frame garbage line
local line = {}

function love.update()
	prof.push("frame")
	
	prof.push("baseline")
		maintain_baseline()
	prof.pop("baseline")

	prof.push("churn")
		--this line is all churn; each segment is a table of 2 random values;
		--the table is regenerated every frame
		line = {}
		for i = 1, churn do
			table.insert(line, {love.math.random(), love.math.random()})
		end
	prof.pop("churn")
end

function love.draw()
	prof.push("draw")
		prof.push("clear")
			love.graphics.clear(0.5, 0.5, 0.5, 1.0)
		prof.pop("clear")
		
		prof.push("line")
			local xs = love.graphics.getWidth() / #line
			local ys = 80
			local y0 = love.graphics.getHeight() - 160
			for i, v in ipairs(line) do
				local x1, y1 = (i - 1), v[1]
				local x2, y2 = i, v[2]
				love.graphics.line(
					x1 * xs, y1 * ys + y0,
					x2 * xs, y2 * ys + y0
				)
			end
		prof.pop("line")

		prof.push("text")
			--render some debug text so we can see what's going on
			love.graphics.print(string.format("churn: %8d\nbaseline%8d", churn, baseline), 10, 10)
			for i, v in ipairs(keybinds_in_order) do
				love.graphics.print(table.concat{v[1], ": ", v[2]}, 10, 40 + i * 17)
			end
		prof.pop("text")
	prof.pop("draw")
	prof.pop("frame")
end

function love.keypressed(k)
	--do keybind callbacks
	if keybinds_map[k] then
		keybinds_map[k]()
	end
end