module DragonSkeleton::Screen

Contains methods for working with a low-resolution screen.

First, you need to create a screen object via ::with_resolution.

screen = Screen.with_resolution(320, 180)

Then you must prepare render target with ::build_render_target to draw to the screen.

render_target = Screen.build_render_target(args, screen)
render_target.primitives << { x: 20, y: 20, w: 32, h: 32, path: 'character.png' }.sprite!

Finally, you need to draw the screen to the main render area using ::sprite.

args.outputs.primitives << Screen.sprite(screen)

Constants

GBA_STYLE: 320x180
LOWREZJAM: 64x64
NOKIA_3310: 84x48
SNES_STYLE: 427x240

Public Class Methods

build_render_target(args, screen) click to toggle source

Creates a render target used to render to the given screen.

# File lib/dragon_skeleton/screen.rb, line 44
def build_render_target(args, screen)
  result = args.outputs[:screen]
  result.width = screen[:x_resolution]
  result.height = screen[:y_resolution]
  result.transient!
  result
end

pixel_rect(screen, screen_position) click to toggle source

Returns the rectangle on the display where the pixel at the given screen position is drawn.

# File lib/dragon_skeleton/screen.rb, line 67
def pixel_rect(screen, screen_position)
  {
    x: screen[:x] + (screen_position.x * screen[:scale]),
    y: screen[:y] + (screen_position.y * screen[:scale]),
    w: screen[:scale],
    h: screen[:scale]
  }
end

sprite(screen) click to toggle source

Creates a sprite that is used to draw the given screen to the display.

# File lib/dragon_skeleton/screen.rb, line 53
def sprite(screen)
  screen.slice(:x, :y, :w, :h).sprite!(path: :screen)
end

to_screen_position(screen, position) click to toggle source

Converts a display position to coordinates on the given screen.

# File lib/dragon_skeleton/screen.rb, line 58
def to_screen_position(screen, position)
  {
    x: (position.x - screen[:x]).idiv(screen[:scale]),
    y: (position.y - screen[:y]).idiv(screen[:scale])
  }
end

with_resolution(x_resolution, y_resolution, scale: nil, render_position: nil) click to toggle source

Creates a screen object with the given resolution.

The scale of the screen (2 for example meaning the screen is rendered at double size) is automatically calculated from the resolution to fit into 1280x720.

The position of the screen is automatically calculated to be centered on the display.

Both the scale and position can be overridden via the scale and render_position keyword arguments.

# File lib/dragon_skeleton/screen.rb, line 29
def with_resolution(x_resolution, y_resolution, scale: nil, render_position: nil)
  scale ||= [1280.idiv(x_resolution), 720.idiv(y_resolution)].min
  w = x_resolution * scale
  h = y_resolution * scale
  render_position ||= { x: (1280 - w).idiv(2), y: (720 - h).idiv(2) }
  render_position.merge(
    x_resolution: x_resolution,
    y_resolution: y_resolution,
    w: w,
    h: h,
    scale: scale
  )
end