README.md

Pico-Kit 📐

A collection of helpers to make your life easier. Comes with four libraries:

• oop

  • oop.class(properties?, parents?, constructor?, metatable?) -> table

    A multi-purpose class creator that returns a table that can be called with a table of properties to generate class instances. The class's constructor is automatically generated and does the following for every parent and then current instance:

    • checks that all required properties are satisfied
    • copies over first the default properties and then the properties passed to the constructor to the instance table
    • calls the provided constructor argument (if it exists)

    Detailed explanation of arguments:

    • properties: A table of property keys/values that will be copied down to every instances. Properties with a value of "req" are considered unset and are required to be provided on an instance creation.
    • parents: A list of parents. The class's __index is set to these parents. Their constructors are also automatically called upon an instance creation.
    • constructor: A function called at the end of instance creation.
    • metatable: A metatable passed to every instance.

• tools

  • tools.assign(table, initial={}) -> table

    Similar to javascript's Object.assign: copies over a table to an empty table, or, if provided, an existing table.

  • tools.assigndeep(table, initial={}) -> table

    Similar to tools.assign but it iterates through tables, effectively performing a deep copy.

• debug

  • debug.tstr(table, indent?) -> str

    Converts a table to a string, optionally indenting each line with indent number of spaces.

  • debug.print(...)

    Prints values to the console with printh. If it encounters nil it prints nil, and if it encounters a table it uses debug.tstr to print out the entire table. Very useful for debugging because not only can you print multiple values at once, but tstr allows you to see the entire contents of even a nested table.

• physics

  • physics.collided(body1, body2) -> bool

    Returns whether two bodies intersect.

  • physics.world(parameters) -> world

    • properties

      • bodies={}

      • gravity={0, .5} a vector that is applied with body.shove to every body during world.update, taking into consideration each bodies' weight and mass

    • physics.world:update()

      For each non-static body: applies gravity, friction, checks for collisions and then updates the position. Call this every frame.

    • physics.world:addbody(body) -> body

      Adds a body to the world and returns it.

  • physics.body(parameters) -> body

    A single physics body.

    • properties

      • pos="req"
      • size="req"
      • vel={0, 0}
      • mass={1, 1} proportionally affects all body.shove and body.slow calls
      • weight={1, 1} proportionally affects all gravity applied to the body
      • friction={.1, 0} applied with body.slow every world.update call, proportionally affects velocity
      • collisions={} a list of object collisions, reset during world.update call
      • static=false a static object that is ignored during world.update
      • layer=0x1 a binary field that represents collision layers. Every world.update calls a band operation between two bodies' layer properties determines whether they will be checked for a collision.

    • physics.body:update()

      Adds the current velocity to the position.

    • physics.body:shove(vector)

      For x and y, adds the vector multiplied by body.mass to the current velocity.

    • physics.body:slow(vector)

      For x and y, subtracts the vector multiplied by body.mass from the current velocity. If the result of this operation crosses 0, the velocity on the corresponding axis is set to 0.

    • physics.body:checkcollided(body)

      For x and y, checks if the current body and provided body would have collided with that axis of the body's velocity, and if so:

      • Adds the provided body to body.collisions.
      • Adjusts the body's position on that axis to the edge of the provided object.
      • Sets that axis of the body's velocity to 0.

Setting up

To use this library, just download the starter.p8 file and open it in Pico. Check out example.p8 for a little example game.

Contributing

Suggested edits are welcome! Just create a pull request and make sure to edit both the starter and example files.