mirror of
https://github.com/vrld/HC.git
synced 2024-11-18 12:54:23 +00:00
304 lines
7.2 KiB
ReStructuredText
304 lines
7.2 KiB
ReStructuredText
HC.shapes
|
|
=========
|
|
|
|
::
|
|
|
|
shapes = require 'HC.shapes'
|
|
|
|
Shape classes with collision detection methods.
|
|
|
|
This module defines methods to move, rotate and draw shapes created with the
|
|
main module.
|
|
|
|
As each shape is at it's core a Lua table, you can attach values and add
|
|
functions to it. Be careful not to use keys that name a function or start with
|
|
an underscore, e.g. `move` or `_rotation`, since these are used internally.
|
|
Everything else is fine.
|
|
|
|
If you don't want to use the full blown module, you can still use these classes
|
|
to test for colliding shapes.
|
|
This may be useful for scenes where the shapes don't move very much and only
|
|
few collisions are of interest - for example graphical user interfaces.
|
|
|
|
|
|
.. _shape-baseclass:
|
|
|
|
Base Class
|
|
----------
|
|
|
|
.. class:: Shape(type)
|
|
|
|
:param any type: Arbitrary type identifier of the shape's type.
|
|
|
|
Base class for all shapes. All shapes must conform to the interface defined below.
|
|
|
|
.. function:: Shape:move(dx, dy)
|
|
|
|
:param numbers dx,dy: Coordinates to move the shape by.
|
|
|
|
Move the shape *by* some distance.
|
|
|
|
**Example**::
|
|
|
|
circle:move(10, 15) -- move the circle 10 units right and 15 units down.
|
|
|
|
|
|
.. function:: Shape:moveTo(x, y)
|
|
|
|
:param numbers x,y: Coordinates to move the shape to.
|
|
|
|
Move the shape *to* some point. Most shapes will be *centered* on the point
|
|
``(x,y)``.
|
|
|
|
.. note::
|
|
Equivalent to::
|
|
|
|
local cx,cy = shape:center()
|
|
shape:move(x-cx, y-cy)
|
|
|
|
**Example**::
|
|
|
|
local x,y = love.mouse.getPosition()
|
|
circle:moveTo(x, y) -- move the circle with the mouse
|
|
|
|
|
|
.. function:: Shape:center()
|
|
|
|
:returns: ``x, y`` - The center of the shape.
|
|
|
|
Get the shape's center.
|
|
|
|
**Example**::
|
|
|
|
local cx, cy = circle:center()
|
|
print("Circle at:", cx, cy)
|
|
|
|
.. function:: Shape:rotate(angle[, cx, cy])
|
|
|
|
:param number angle: Amount of rotation in radians.
|
|
:param numbers cx, cy: Rotation center; defaults to the shape's center if omitted (optional).
|
|
|
|
Rotate the shape *by* some angle. A rotation center can be specified. If no
|
|
center is given, rotate around the center of the shape.
|
|
|
|
**Example**::
|
|
|
|
rectangle:rotate(math.pi/4)
|
|
|
|
|
|
.. function:: Shape:setRotation(angle[, cx, cy])
|
|
|
|
:param number angle: Amount of rotation in radians.
|
|
:param numbers cx, cy: Rotation center; defaults to the shape's center if omitted (optional).
|
|
|
|
Set the rotation of a shape. A rotation center can be specified. If no center
|
|
is given, rotate around the center of the shape.
|
|
|
|
.. note::
|
|
Equivalent to::
|
|
|
|
shape:rotate(angle - shape.rotation(), cx,cy)
|
|
|
|
**Example**::
|
|
|
|
rectangle:setRotation(math.pi, 100,100)
|
|
|
|
|
|
.. function:: Shape:rotation()
|
|
|
|
:returns: The shape's rotation in radians.
|
|
|
|
Get the rotation of the shape in radians.
|
|
|
|
|
|
.. function:: Shape:scale(s)
|
|
|
|
:param number s: Scale factor; must be > 0.
|
|
|
|
Scale the shape relative to it's center.
|
|
|
|
.. note::
|
|
|
|
There is no way to query the scale of a shape.
|
|
|
|
**Example**::
|
|
|
|
circle:scale(2) -- double the size
|
|
|
|
|
|
.. function:: Shape:outcircle()
|
|
|
|
:returns: ``x, y, r`` - Parameters of the outcircle.
|
|
|
|
Get parameters of a circle that fully encloses the shape.
|
|
|
|
**Example**::
|
|
|
|
if player:hasShield() then
|
|
love.graphics.circle('line', player:outcircle())
|
|
end
|
|
|
|
.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
|
|
|
|
.. function:: Shape:bbox()
|
|
|
|
:returns: ``x1, y1, x2, y2`` - Corners of the counding box.
|
|
|
|
Get axis aligned bounding box.
|
|
``x1, y1`` defines the upper left corner, while ``x2, y2`` define the lower
|
|
right corner.
|
|
|
|
**Example**::
|
|
|
|
-- draw bounding box
|
|
local x1,y1, x2,y2 = shape:bbox()
|
|
love.graphics.rectangle('line', x1,y1, x2-x1,y2-y1)
|
|
|
|
|
|
.. function:: Shape:draw(mode)
|
|
|
|
:param DrawMode mode: How to draw the shape. Either 'line' or 'fill'.
|
|
|
|
Draw the shape either filled or as outline. Mostly for debug-purposes.
|
|
|
|
**Example**::
|
|
|
|
circle:draw('fill')
|
|
|
|
.. function:: Shape:support(dx,dy)
|
|
|
|
:param numbers dx, dy: Search direction.
|
|
:returns: The furthest vertex in direction `dx, dy`.
|
|
|
|
Get furthest vertex of the shape with respect to the direction ``dx, dy``.
|
|
|
|
Used in the collision detection algorithm, but may be useful for other things -
|
|
e.g. lighting - too.
|
|
|
|
**Example**::
|
|
|
|
-- get vertices that produce a shadow volume
|
|
local x1,y1 = circle:support(lx, ly)
|
|
local x2,y2 = circle:support(-lx, -ly)
|
|
|
|
|
|
.. function:: Shape:collidesWith(other)
|
|
|
|
:param Shape other: Test for collision with this shape.
|
|
:returns: ``collide, dx, dy`` - Collision indicator and separating vector.
|
|
|
|
Test if two shapes collide.
|
|
|
|
The separating vector ``dx, dy`` will only be defined if ``collide`` is ``true``.
|
|
If defined, the separating vector will point in the direction of ``other``,
|
|
i.e. ``dx, dy`` is the direction and magnitude to move ``other`` so that the
|
|
shapes do not collide anymore.
|
|
|
|
**Example**::
|
|
|
|
if circle:collidesWith(rectangle) then
|
|
print("collision detected!")
|
|
end
|
|
|
|
|
|
.. function:: Shape:contains(x, y)
|
|
|
|
:param numbers x, y: Point to test.
|
|
:returns: ``true`` if ``x,y`` lies in the interior of the shape.
|
|
|
|
Test if the shape contains a given point.
|
|
|
|
**Example**::
|
|
|
|
if unit.shape:contains(love.mouse.getPosition) then
|
|
unit:setHovered(true)
|
|
end
|
|
|
|
|
|
.. function:: Shape:intersectionsWithRay(x, y, dx, dy)
|
|
|
|
:param numbers x, y: Starting point of the ray.
|
|
:param numbers dx, dy: Direction of the ray.
|
|
:returns: Table of ray parameters.
|
|
|
|
Test if the shape intersects the given ray.
|
|
The ray parameters of the intersections are returned as a table.
|
|
The position of the intersections can be computed as
|
|
``(x,y) + ray_parameter * (dx, dy)``.
|
|
|
|
|
|
**Example**::
|
|
|
|
local ts = player:intersectionsWithRay(x,y, dx,dy)
|
|
for _, t in ipairs(t) do
|
|
-- find point of intersection
|
|
local vx,vy = vector.add(x, y, vector.mul(t, dx, dy))
|
|
player:addMark(vx,vy)
|
|
end
|
|
|
|
|
|
.. function:: Shape:intersectsRay(x, y, dx, dy)
|
|
|
|
:param numbers x, y: Starting point of the ray.
|
|
:param numbers dx, dy: Direction of the ray.
|
|
:returns: ``intersects, ray_parameter`` - intersection indicator and ray paremter.
|
|
|
|
Test if the shape intersects the given ray.
|
|
If the shape intersects the ray, the point of intersection can be computed by
|
|
``(x,y) + ray_parameter * (dx, dy)``.
|
|
|
|
|
|
**Example**::
|
|
|
|
local intersecting, t = player:intersectsRay(x,y, dx,dy)
|
|
if intersecting then
|
|
-- find point of intersection
|
|
local vx,vy = vector.add(x, y, vector.mul(t, dx, dy))
|
|
player:addMark(vx,vy)
|
|
end
|
|
|
|
|
|
|
|
.. _custom-shapes:
|
|
|
|
Custom Shapes
|
|
-------------
|
|
|
|
Custom shapes must implement at least the following methods (as defined above)
|
|
|
|
- :func:`Shape:move`
|
|
- :func:`Shape:rotate`
|
|
- :func:`Shape:scale`
|
|
- :func:`Shape:bbox`
|
|
- :func:`Shape:collidesWith`
|
|
|
|
|
|
.. _builtin-shapes:
|
|
|
|
Built-in Shapes
|
|
---------------
|
|
|
|
.. class:: ConcavePolygonShape
|
|
|
|
.. class:: ConvexPolygonShape
|
|
|
|
.. class:: CircleShape
|
|
|
|
.. class:: PointShape
|
|
|
|
.. function:: newPolygonShape(...)
|
|
|
|
:param numbers ...: Vertices of the :class:`Polygon`.
|
|
:returns: :class:`ConcavePolygonShape` or :class:`ConvexPolygonShape`.
|
|
|
|
.. function:: newCircleShape(cx, cy, radius)
|
|
|
|
:param numbers cx,cy: Center of the circle.
|
|
:param number radius: Radius of the circle.
|
|
:returns: :class:`CircleShape`.
|
|
|
|
.. function:: newPointShape
|
|
|
|
:param numbers x, y: Position of the point.
|
|
:returns: :class:`PointShape`.
|