Light & Shadow

A simple dynamic light shadow library for LOVE2D 11.2.

It's easy to use, don't need to create body for shadow, directly generate shadow from canvas/image according alpha. So it's not fast, and don't support 3D shadow. If you want a fast and 3D light shadow library, Light World and Shadow is better choice.

Example

##Usage

local Lib = require 'light'
local light_world = Lib.World.new()
local light

local lg = love.grpahics

function love.load()
  light = light_world:add(200, 200, 200, 1, 0, 0)
end

function love.update(dt)
  light.x, light.y = love.mouse.getPosition()
end

function love.draw()
  -- reset light world
  light_world:begin()

  for i = 1, 10 do
    lg.circle('fill', 100 + i * 70, 300, 10)
  end

  -- track shadow objects
  light_world:track_obj()
  for i = 1, 10 do
    lg.circle('fill', 100 + i * 70, 300 + i * 50, 30)
  end
  -- draw background
  light_world:track_bg()

  for i = 1, 10 do
    lg.circle('fill', 100 + i * 70, 500 + i * 50, 30)
  end

  -- draw scene, light and shadow
  light_world:finish()

  lg.print('mouse: '..mx..','..my..' light: '..light.x..','..light.y, 50, 50)
end

Functions

World

• World.new({ env_light = { 0.5, 0.4, 0.5, 0.5 }, alpha_through = 0.3 }) if a object alpha less than alpha_through, we will not generate shadow for it
• World:begin() reset light world and start track background pixels.
• World:track_obj() switch to draw object mode, pixels is affected by light and has shadow.
• World:track_light_objs() switch to draw object mode, pixels is always light and has shadow.
• World:track_bg() switch to draw background mode, new pixels is affected by light.
• World:track_light_bg() switch to draw background mode, the pixels always is light and it has no shadow
• World:finish() draw bg, objects, light and shadow to screen.
• World:add(x, y, radius, r, g, b, a) add a light to world, return light
• World:remove(light) remove the light from world
• World:clear() remove all lights
• World:setEnvLight(r, g, b, a)
• World:resize(w, h) you must call it after change window size
• World:setTranslate(x, y, scale) you must call it if your applied love.graphics.translate or love.graphics.scale
• World.env_tex=[canvas/image]
• World.pause=true Stop light and shadow feature.

Light

• Light:setSize(radius) resize the light

Tips

• If the env_light is 1, 1, 1, 1, no light and shadow can be draw. In an overly bright environment you will not see light and shadow
• If the background alpha is too little, we will not see the light because no object can reflect this light into your eyes
• When you have a lot of light, it will very slow. the light size and quantity will affect performance. (I will try to make it faster)

TODO

• Fix shadow for source_radius argument.
• Support shadow for semitransparent objects.(shadow map able to save four floats.)
• Optimize according to here