Module libre_pvz::core::kinematics

Kinematics for projectiles and other movable entities.

All the movable entities live in a right-handed pseudo-3D world. The XY plane lies on the ground, with the X axis points right, and the Y axis points up. The Z axis is for height, and coincides with Y axis on the viewport. This coordinate system has the following benefits:

• it easily translates to the viewport coordinate (x <- x, y <- y + z);
• it avoids false collision (it distinguishes between “at the back” and “high in the sky”);
• it allows objects to correctly drop their shadows;

All entities have a planar collide box in the 2D world. During collision detection, the collide boxes are laid out parallel to the XZ plane, and then pushed along the Y axis to form a cuboid.

Structs

• Acceleration
  Acceleration (in length per square second).
• KinematicsPlugin
  Kinematics plugin for all movable entities.
• Position
  Position.
• Velocity
  Velocity (in length per second).

Enums

• KineticsSystem
  System label for kinetics systems.

Functions

• acceleration_system
  Update velocity from acceleration.
• coordinate_translation_system
  Coordinate translation from pseudo 3D to 2D.
• movement_system
  Update position from velocity.