lovexp/asteroids/actors.lua

local love = require("love")
local phys = require("phys")
local inspect = require("inspect")

local actors = {}

function actors.buildActors(game)
    local asteroids = {}
    local asteroids_mt = { __index = asteroids }

    function asteroids.new(asteroid)
        local stageIndex = asteroid.stage or #game.asteroids.stages
        local stage = game.asteroids.stages[stageIndex]
        local instance = {
            angle = math.random() * phys.tau,
            speed = stage.speed,
            facing = math.random() * phys.tau,
            spin = (math.random() - 0.5),
            radius = stage.radius,
            sprite = stage.sprite,
        }
        for k, v in pairs(asteroid) do
            instance[k] = v
        end
        instance.stage = stageIndex
        setmetatable(instance, asteroids_mt)
        return instance
    end

    function asteroids:draw()
        local width = self.sprite:getWidth()
        local height = self.sprite:getHeight()
        love.graphics.push()
        love.graphics.setColor(1, 1, 1)
        local scale = 2 * self.radius / math.max(width, height)
        love.graphics.draw(self.sprite,
            self.x,
            self.y,
            self.facing,
            scale,
            scale,
            width / 2,
            height / 2
        )
        love.graphics.pop()
    end

    local bullets = {}
    local bullets_mt = { __index = bullets }

    function bullets.new(bullet)
        local instance = {
            spin = 0,
        }
        for k, v in pairs(game.ship.bullet) do
            instance[k] = v
        end
        for k, v in pairs(bullet) do
            instance[k] = v
        end
        instance.sound = love.audio.newSource(game.ship.bullet.sound)
        instance.timeLeft = instance.time
        setmetatable(instance, bullets_mt)
        return instance
    end

    function bullets:draw()
        love.graphics.push()
        love.graphics.setColor(0, 1, 0)
        love.graphics.circle('fill', self.x, self.y, self.radius)
        love.graphics.pop()
    end

    local ships = {}
    local ships_mt = { __index = ships }

    function ships.new(ship)
        local instance = {
            x = game.width / 2,
            y = game.height / 2,
            angle = 0,
            speed = 0,
            spin = 0,
            facing = phys.tau * 3 / 4,
            radius = game.ship.radius,
            throttle = 0,
        }
        for k, v in pairs(game.ship) do
            instance[k] = v
        end
        for k, v in pairs(ship) do
            instance[k] = v
        end
        instance.engineSound = love.audio.newSource(instance.engineSound)
        instance.engineSound:setVolume(0)
        instance.engineSound:setLooping(true)
        instance.rocketPlume = love.graphics.newParticleSystem(instance.rocketPlume)
        instance.rocketPlume:setColors(
            0.37, 0.65, 1.00, 0.8,
            0.45, 0.65, 0.9, 0.8,
            0.5, 0.6, 0.85, 0.8
        )
        instance.rocketPlume:setSizes(1.0, 0.9, 0.1)
        instance.rocketPlume:setEmissionRate(1000)
        -- TODO probably governed most by thrust
        instance.rocketPlume:setParticleLifetime(0.1, 0.25)
        instance.rocketPlume:setEmissionArea('normal', 1.5, 1.5)
        instance.rocketPlume:setSpeed(150, 300)
        instance.rocketPlume:setRadialAcceleration(40, 80)
        instance.rocketPlume:setLinearDamping(0, 0)
        instance.rocketPlume:setDirection(phys.tau * 3 / 4)
        instance.rocketPlume:setSpread(0)
        instance.rocketPlume:setSizeVariation(0)
        instance.rocketPlume:setSpin(0.5, 1)
        instance.rocketPlume:setTangentialAcceleration(0, 0)

        setmetatable(instance, ships_mt)
        return instance
    end

    function ships:draw()
        love.graphics.push()
        love.graphics.translate(self.x, self.y)
        love.graphics.setColor(1, 1, 1)
        local width = self.sprite:getWidth()
        local height = self.sprite:getHeight()

        local scale = 2 * game.ship.radius / math.max(width, height)
        love.graphics.draw(game.ship.sprite,
            0,
            0,
            (self.facing + phys.tau / 4) % phys.tau,
            scale,
            scale,
            width / 2,
            height / 2
        )
        self.rocketPlume:setEmissionRate(1000 * self.throttle)
        love.graphics.draw(self.rocketPlume,
            0,
            0,
            (self.facing + phys.tau * 3 / 4) % phys.tau,
            scale,
            scale,
            0,
            height * 0.6
        )
        love.graphics.pop()
    end

    return {
        asteroids = asteroids,
        bullets = bullets,
        ships = ships,
    }
end

return actors