Triangles - Small library to draw delaunay triangle geometry on LOVE.

init.lua

--
-- triangles
--
-- The MIT License (MIT)
--
-- Copyright (c) 2014, DesertRock
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy
-- of this software and associated documentation files (the "Software"), to deal
-- in the Software without restriction, including without limitation the rights
-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-- copies of the Software, and to permit persons to whom the Software is
-- furnished to do so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in
-- all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-- THE SOFTWARE.
--
-- Notice that this license does not apply to the dependancy on the delaunay
-- library made by Yonaba that can be found here: tps://github.com/Yonaba/delaunay
--
-- To use, put the delaunay.lua file in a folder along with this file. You then
-- can do a `Triangles = require("triangles")`.
-- To create a triangles object, you do Triangles:new(). After that you do
-- Triangles:generate(width,height,cellsize,cellvariance). If you want to color
-- the triangles, do :colorize(lines). If lines is true, it will draw outlines.
-- Look at main.lua below for an example.

local Delaunay = require( ... .. '.delaunay') -- https://github.com/Yonaba/delaunay

--Stolen from: https://github.com/EmmanuelOga/columns/blob/master/utils/color.lua
local function hslToRgb(h, s, l, a)
  local r, g, b

  if s == 0 then
    r, g, b = l, l, l -- achromatic
  else
    function hue2rgb(p, q, t)
      if t < 0   then t = t + 1 end
      if t > 1   then t = t - 1 end
      if t < 1/6 then return p + (q - p) * 6 * t end
      if t < 1/2 then return q end
      if t < 2/3 then return p + (q - p) * (2/3 - t) * 6 end
      return p
    end

    local q
    if l < 0.5 then q = l * (1 + s) else q = l + s - l * s end
    local p = 2 * l - q

    r = hue2rgb(p, q, h + 1/3)
    g = hue2rgb(p, q, h)
    b = hue2rgb(p, q, h - 1/3)
  end

  return {r * 255, g * 255, b * 255, a * 255}
end

local Triangles = {}
Triangles.__index = Triangles

function Triangles:new(i)
    local o = {}
    o = {}
    o.points = {}
    o.triangles = nil
    o.cs = 100
    o.cp = 15
    o.noffx = 0
    o.noffy = 0
    o.freq = 1000
    o.saturation = 0.5
    o.lightness = 0.5
    o.linecolor = {0,0,0}
    o.hueoff = 0
    o.huemult = 1

    setmetatable(o, self)
    return o
end

function Triangles:generate(w,h,csize,padding)
    self.points = {}
    self.cs = csize or 100
    self.cp = padding or 15
    local cellrows = 1+ w/self.cs
    local cellcols = 1+ h/self.cs
    for x=-1,cellrows do
        for y=-1,cellcols do
            local xx = x*self.cs + love.math.random(self.cp*2) - self.cp
            local yy = y*self.cs + love.math.random(self.cp*2) - self.cp
            table.insert(self.points,Delaunay.Point(xx,yy))
        end
    end

    self.noffx,self.noffy = love.math.random(10000),love.math.random(10000)

    self.triangles = Delaunay.triangulate(unpack(self.points))
    for _,tri in ipairs(self.triangles) do
        tri.color = {100,100,100}
    end
    return self
end

function Triangles:getColor(x,y)
    local hue = love.math.noise( self.noffx+x/self.freq,self.noffy+y/self.freq )*self.huemult + self.hueoff
    while hue > 1.0 do
        hue = hue-1
    end
    while hue < 0 do
        hue = hue + 1
    end
    return hslToRgb(hue,self.saturation,self.lightness,1)
end

function Triangles:colorize()
    for _,tri in ipairs(self.triangles) do
        tri.color = self:getColor(tri:getCenter())
    end
    return self
end

function Triangles:draw(lines)
    for _,tri in ipairs(self.triangles) do
        love.graphics.setColor(unpack(tri.color))
        love.graphics.polygon( "fill", tri.p1.x,tri.p1.y,tri.p2.x,tri.p2.y,tri.p3.x,tri.p3.y)
        if lines then
            love.graphics.setColor(unpack(self.linecolor))
            love.graphics.polygon( "line", tri.p1.x,tri.p1.y,tri.p2.x,tri.p2.y,tri.p3.x,tri.p3.y)
        end
    end
end

return Triangles

main.lua

Triangles = require("triangles")

function love.load()
    for i=0,20 do
        love.math.random();love.math.random();love.math.random();love.math.random()
    end
    love.graphics.setBackgroundColor( 220, 220, 220 )
    tris = Triangles:new():generate(love.graphics.getWidth(),love.graphics.getHeight(),30,10)
    -- tris:colorize()
    tris.lightness = 0.5
    tris.saturation = 0.3
    tris.hueoff = love.math.random()
    tris.huemult = 0.3
end

function love.update(dt)
    -- tris.noffx = tris.noffx+dt/4
    -- tris.noffy = tris.noffx+dt/20
    tris.hueoff = tris.hueoff+dt/20
    tris:colorize()
end
function love.draw()
    tris:draw()
end