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# Focused tutorial video: https://s3.amazonaws.com/s3.dragonruby.org/dragonruby-nddnug-workshop.mp4
# Workshop/Presentation which provides motivation for creating a game engine: https://www.youtube.com/watch?v=S3CFce1arC8
def defaults args
args.outputs.background_color = [0, 0, 0]
args.state.x ||= 640
args.state.y ||= 360
args.state.stars ||= 100.map do
[1280 * rand, 720 * rand, rand.fdiv(10), 255 * rand, 255 * rand, 255 * rand]
end
args.state.sun ||= args.state.new_entity(:sun) do |s|
s.s = 100
s.path = 'sprites/sun.png'
end
args.state.planets = [
[:mercury, 65, 5, 88],
[:venus, 100, 10, 225],
[:earth, 120, 10, 365],
[:mars, 140, 8, 687],
[:jupiter, 280, 30, 365 * 11.8],
[:saturn, 350, 20, 365 * 29.5],
[:uranus, 400, 15, 365 * 84],
[:neptune, 440, 15, 365 * 164.8],
[:pluto, 480, 5, 365 * 247.8],
].map do |name, distance, size, year_in_days|
args.state.new_entity(name) do |p|
p.path = "sprites/#{name}.png"
p.distance = distance * 0.7
p.s = size * 0.7
p.year_in_days = year_in_days
end
end
args.state.ship ||= args.state.new_entity(:ship) do |s|
s.x = 1280 * rand
s.y = 720 * rand
s.angle = 0
end
end
def to_sprite args, entity
x = 0
y = 0
if entity.year_in_days
day = args.state.tick_count
day_in_year = day % entity.year_in_days
entity.random_start_day ||= day_in_year * rand
percentage_of_year = day_in_year.fdiv(entity.year_in_days)
angle = 365 * percentage_of_year
x = angle.vector_x(entity.distance)
y = angle.vector_y(entity.distance)
end
[640 + x - entity.s.half, 360 + y - entity.s.half, entity.s, entity.s, entity.path]
end
def render args
args.outputs.solids << [0, 0, 1280, 720]
args.outputs.sprites << args.state.stars.map do |x, y, _, r, g, b|
[x, y, 10, 10, 'sprites/star.png', 0, 100, r, g, b]
end
args.outputs.sprites << to_sprite(args, args.state.sun)
args.outputs.sprites << args.state.planets.map { |p| to_sprite args, p }
args.outputs.sprites << [args.state.ship.x, args.state.ship.y, 20, 20, 'sprites/ship.png', args.state.ship.angle]
end
def calc args
args.state.stars = args.state.stars.map do |x, y, speed, r, g, b|
x += speed
y += speed
x = 0 if x > 1280
y = 0 if y > 720
[x, y, speed, r, g, b]
end
if args.state.tick_count == 0
args.outputs.sounds << 'sounds/bg.ogg'
end
end
def process_inputs args
if args.inputs.keyboard.left || args.inputs.controller_one.key_held.left
args.state.ship.angle += 1
elsif args.inputs.keyboard.right || args.inputs.controller_one.key_held.right
args.state.ship.angle -= 1
end
if args.inputs.keyboard.up || args.inputs.controller_one.key_held.a
args.state.ship.x += args.state.ship.angle.x_vector
args.state.ship.y += args.state.ship.angle.y_vector
end
end
def tick args
defaults args
render args
calc args
process_inputs args
end
def r
$gtk.reset
end
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