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How to apply random sizes and colors to points

https://love2d.org./forums/viewtopic.php?t=91646

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How to apply random sizes and colors to points

Posted: Thu Jul 15, 2021 3:02 pm
by klewis
Hello, I'm trying to randomize sizes and colors for the use of love.graphics.points()

I've been playing with the following logic to give it a go. What can I do to get closer to my goal?

Code: Select all

function love.load()
    local screen_width, screen_height = love.graphics.getDimensions()
    local max_stars = 100 -- how many stars we want

    stars = {} -- table which will hold our stars

    for i = 1, max_stars do -- generate the coords of our stars
        local x = love.math.random(5, screen_width - 5) -- generate a "random" number for the x coord of this star
        local y = love.math.random(5, screen_height - 5) -- both coords are limited to the screen size, minus 5 pixels of padding
        stars[i] = {x, y} -- stick the values into the table
    end
end

function love.draw()
    love.graphics.setPointSize(3)
    love.graphics.points(stars) -- draw all stars as points
end

Re: How to apply random sizes and colors to points

Posted: Thu Jul 15, 2021 4:22 pm
by darkfrei
Use circles, not points:

Code: Select all

function love.load()
	local screen_width, screen_height = love.graphics.getDimensions()
	local max_stars = 100	-- how many stars we want

	stars = {}	-- table which will hold our stars

	for i=1, max_stars do	-- generate the coords of our stars
		local x = love.math.random(5, screen_width-5)	-- generate a "random" number for the x coord of this star
		local y = love.math.random(5, screen_height-5)	-- both coords are limited to the screen size, minus 5 pixels of padding
		local r = math.random(1, 3)
		local color = {0.5+0.5*math.random(), 0.5+0.5*math.random(), 0.5+0.5*math.random()}
		local star = {x=x, y=y, r=r, color = color}
		table.insert (stars, star)	-- stick the values into the table
	end
end

function love.draw()
	for i, star in pairs (stars) do
		love.graphics.setColor(star.color)
		love.graphics.circle('fill', star.x, star.y, star.r)
	end
end

`

Posted: Thu Jul 15, 2021 5:19 pm
by klewis
A million thanks on showing me a way to think about and tackle my situation to reach my goal. This looks amazing. and we are using pairs because of our custom key value pairs.

Thanks again!

Re: `

Posted: Thu Jul 15, 2021 8:13 pm
by darkfrei
klewis wrote: ↑Thu Jul 15, 2021 5:19 pm A million thanks on showing me a way to think about and tackle my situation to reach my goal. This looks amazing. and we are using pairs because of our custom key value pairs.

Thanks again!
And moving stars:

Code: Select all

function new_star ()
	local padding = 5
	local x = love.math.random(padding, screen_width-padding)	-- generate a "random" number for the x coord of this star
	local y = love.math.random(padding, screen_height-padding)	-- both coords are limited to the screen size, minus 5 pixels of padding
	local r = math.random(1, 3)
--	local r = 1
	local color = {0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5}
	local star = {x=x, y=y, r=r, color = color}
	return star
end

function love.load()
	screen_width, screen_height = love.graphics.getDimensions()
	center = {x=screen_width/2, y=screen_height/2}
	local max_stars = 100	-- how many stars we want

	stars = {}	-- table which will hold our stars

	for i=1, max_stars do	-- generate the coords of our stars
		local star = new_star ()
		table.insert (stars, star)	-- stick the values into the table
	end
end

function love.update(dt)
	for i, star in pairs (stars) do
		star.x = star.x + dt*(star.x-center.x)
		star.y = star.y + dt*(star.y-center.y)
		star.r = star.r + dt*2
		if (star.x < 0) or (star.y < 0) or (star.x > screen_width) or (star.y > screen_height) then
			-- out of screen, replace the star with the new one
			stars[i] = new_star ()
		end
	end
end

function love.draw()
	for i, star in pairs (stars) do
		love.graphics.setColor(star.color)
		love.graphics.circle('fill', star.x, star.y, star.r)
	end
end

Re: How to apply random sizes and colors to points

Posted: Thu Jul 15, 2021 11:32 pm
by togFox
Heh. Nice. Can they move right to left instead?

Re: How to apply random sizes and colors to points

Posted: Fri Jul 16, 2021 3:01 am
by darkfrei
togFox wrote: ↑Thu Jul 15, 2021 11:32 pm Heh. Nice. Can they move right to left instead?
Main changing in the update:

Code: Select all

star.x = star.x + dt*(-star.r*100)

Code: Select all

function new_star (bool)
	local padding = 5
	local x = love.math.random(padding, screen_width-padding)	-- generate a "random" number for the x coord of this star
	if bool then -- new stars on edge
		x = screen_width
	end
	local y = love.math.random(padding, screen_height-padding)	-- both coords are limited to the screen size, minus 5 pixels of padding
	local r = 1+5*math.random()^4
--	local r = 1
	local color = {0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5}
	local star = {x=x, y=y, r=r, color = color}
	return star
end

function love.load()
	screen_width, screen_height = love.graphics.getDimensions()
	center = {x=screen_width/2, y=screen_height/2}
	local max_stars = 100	-- how many stars we want

	stars = {}	-- table which will hold our stars

	for i=1, max_stars do	-- generate the coords of our stars
		local star = new_star ()
		table.insert (stars, star)	-- stick the values into the table
	end
end

function love.update(dt)
	for i, star in pairs (stars) do
		star.x = star.x + dt*(-star.r*100)
		if (star.x < 0) or (star.y < 0) or (star.x > screen_width) or (star.y > screen_height) then
			stars[i] = new_star (true) -- out of screen, replace the star with the new one
		end
	end
end

function love.draw()
	for i, star in pairs (stars) do
		love.graphics.setColor(star.color)
		love.graphics.circle('fill', star.x, star.y, star.r)
	end
end

Re: How to apply random sizes and colors to points

Posted: Fri Jul 16, 2021 8:43 am
by darkfrei
But the extra high speed needs lines, not circles:

Code: Select all

function new_star (bool)
	local padding = 5
	local x = love.math.random(padding, screen_width-padding)	-- generate a "random" number for the x coord of this star
	if bool then -- new stars on edge
		x = screen_width
	end
	local y = love.math.random(padding, screen_height-padding)	-- both coords are limited to the screen size, minus 5 pixels of padding
	local r = 0.5+5*math.random()^2
--	local r = 1
	local color = {0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5, 0.5+0.5*love.math.random()^0.5}
	local star = {x=x, y=y, r=r, color = color}
	star.vx = (-star.r*500)*(0.1+0.9*math.random())
	star.x = star.x - (1/60)*star.vx
	
	return star
end

function love.load()
	screen_width, screen_height = love.graphics.getDimensions()
	center = {x=screen_width/2, y=screen_height/2}
	local max_stars = 100	-- how many stars we want

	stars = {}	-- table which will hold our stars

	for i=1, max_stars do	-- generate the coords of our stars
		local star = new_star ()
		table.insert (stars, star)	-- stick the values into the table
	end
end

function love.update(dt)
	for i, star in pairs (stars) do
		star.x = star.x + dt*star.vx
		if (star.x < 0) then
			stars[i] = new_star (true) -- out of screen, replace the star with the new one
		end
	end
end

function love.draw()
	for i, star in pairs (stars) do
		love.graphics.setColor(star.color)
		love.graphics.setLineWidth( star.r/2 )
		love.graphics.line(star.x, star.y, star.x-(star.vx^2)*0.00002, star.y)
	end
end

Re: How to apply random sizes and colors to points

Posted: Fri Jul 16, 2021 9:38 am
by togFox
Looks real. :)

Re: How to apply random sizes and colors to points

Posted: Wed Jun 15, 2022 6:55 pm
by klewistech
@darkfrei thank you so much for the tutorial on this!
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