From c5ad88074c8f14979d1a8db6bab970248e3dbf60 Mon Sep 17 00:00:00 2001 From: Evan Hemsley <2342303+ehemsley@users.noreply.github.com> Date: Tue, 31 Dec 2019 14:37:49 -0800 Subject: [PATCH] adds documentation for AABB and revised IShape2D --- content/api/AABB.md | 27 +++++++++++++++++++++++++++ content/api/IShape2D.md | 15 ++++++++------- 2 files changed, 35 insertions(+), 7 deletions(-) create mode 100644 content/api/AABB.md diff --git a/content/api/AABB.md b/content/api/AABB.md new file mode 100644 index 0000000..93f6dbf --- /dev/null +++ b/content/api/AABB.md @@ -0,0 +1,27 @@ +--- +title: "AABB" +date: 2019-12-31T14:36:00-07:00 +weight: 6 +--- + +*AABB*, or axis-aligned bounding box, is defined by a minimum point and a maximum point. It is used for broad-phase collision detection. It represents a rectangular outline of the shape so we can quickly insert shapes into a *SpatialHash*. + +## Properties + +##### **public Vector2 Min { get; private set; }** + +The minimum point of the AABB. + +##### **public Vector2 Max { get; private set; }** + +The maximum point of the AABB. + +## Methods + +##### **public static AABB FromVertices(IEnumerable vertices)** + +Can be used to generate an AABB from an arbitrary collection of vertices. It is generally better to define a more efficient AABB generation method based on the properties of a particular shape, but this can be used for an arbitrary collection of vertices, like a polygon. + +##### **public static AABB Transformed(AABB aabb, Transform2D transform)** + +Efficiently transforms an AABB. Used internally by SpatialHash to quickly transform a shape's AABB. diff --git a/content/api/IShape2D.md b/content/api/IShape2D.md index 85f9cef..2f01e7b 100644 --- a/content/api/IShape2D.md +++ b/content/api/IShape2D.md @@ -8,6 +8,12 @@ An *IShape2D* is an interface that, when implemented, allows for spatial hashing Your *IShape2D* implementations should be structs for memory efficiency purposes. +## Properties + +##### **public AABB { get; }** + +An axis-aligned bounding box for the shape. This is stored so we can efficiently transform the AABB when necessary. + ## Methods ##### **Vector2 Support(Vector2 direction, Transform2D transform)** @@ -34,13 +40,8 @@ A method which returns the axis-aligned bounding box for the transformed shape. For example, the AABB method for Bonk's *Circle* implementation: ```cs -public AABB AABB(Transform2D Transform2D) +public AABB TransformedAABB(Transform2D Transform2D) { - return new AABB( - Transform2D.Position.X - Radius, - Transform2D.Position.Y - Radius, - Transform2D.Position.X + Radius, - Transform2D.Position.Y + Radius - ); + return AABB.Transformed(AABB, transform2D); } ```