Create ROM Object

A ROM object contains all the static data for running a game. ROM elements can be set with this function or after the fact, e.g. with ROM$framerate = 30.

See vignette("engine") for more info.

Usage

rom.init(
  screen.width,
  screen.height,
  keybinds = c(w = "up", a = "left", s = "down", d = "right"),
  startup = function(RAM) {
     return(RAM)
 },
  custom = function(RAM) {
     return(RAM)
 },
  sprites = list(),
  palette = c("  ", "[]", "  "),
  framerate = 60,
  backup_duration = 2,
  input_delay = 1/60
)

Arguments

screen.width

Width of the game screen in pixels; see render.scene.

screen.height

Height of the game screen in pixels.

keybinds

Vector of keys and their corresponding action; see inputs.process().

startup

Function run by the game when initialized with ram.init(). Must return RAM.

custom

Function run by the game on every frame with ram.tick(). Must return RAM.

sprites

List of all sprites (matrices) used by the game; see render.animate.

palette

Vector of how each value of 0, 1, 2, 3, etc. in a sprite should be drawn by render.matrix().

framerate

Frames per second the game should run at. 60 recommended, 30 may be useful if render.ram() takes a significant amount of time.

backup_duration

How frequently the RAM backs itself up in seconds; see ram.rollback. Shouldn't need to be changed from the default.

input_delay

Seconds to add to the timestamp of every input. Makes inputs get processed slightly after they were sent, to reduce the frequency of rollbacks. Shouldn't need to be changed.

Game Code

ROM$custom updates the RAM every frame in ram.tick(). All game code should be either in ROM$custom or in helper functions stored in the ROM, demonstrated below.

Examples

testrom = rom.init(64,16)
testrom$example_function = function(){print('foo')}
testrom$startup = function(RAM){RAM$ROM$example_function(); return(RAM)}
RAM = ram.init(testrom)
#> [1] "foo"