blaze.collision.shapes.polygon

class PolyDef : blaze.collision.shapes.shape.ShapeDef;

Convex polygon. The vertices must be in CCW order for a right-handed coordinate system with the z-axis coming out of the screen.

Implements:
ShapeDef

bVec2 [] vertices ;

The polygon vertices in local coordinates.

this(float density, bVec2 [] vertices);

Params:

float density	the density of the polygon
verticies	the verticies that make up the polygon

void setAsBox (float hx, float hy);

Build vertices to represent an axis-aligned box.

Params:

float hx	the half-width.
float hy	the half-height.

void setAsBox (float hx, float hy, bVec2 center, float angle);

Build vertices to represent an oriented box.

Params:

float hx	the half-width. hy the = half-height.
bVec2 center	the center of the box in local coordinates.
float angle	the rotation of the box in local coordinates.

class Polygon : blaze.collision.shapes.shape.Shape;

A polygon

Implements:
Shape

this(ShapeDef def);

Constructs a polygon from a ShapeDef

BUGS:
www.dsource.org/forums/viewtopic.php?t=4354&sid=ced13ecab0525aa79a60a826e7290805 This example code demonstrates the failure

 auto sdef = new blaze.PolyDef;
 sdef.vertices ~= Vec2(-.07, -.11);
 sdef.vertices ~= Vec2(.07, -.11);
 sdef.vertices ~= Vec2(.07, .1);
 sdef.vertices ~= Vec2(-.07, .1);

bVec2 firstVertex (bXForm xf);

Returns:
the first vertex and apply the supplied transform.

AABB aabb ();

Returns:
the axis aligned bounding box associated with the shape, in reference to the parent body's transform

void updateAABB ();

Update the AABB

OBB obb ();

Returns:
the oriented bounding box relative to the parent body.

bVec2 centroid ();

Returns:
the local centroid relative to the parent body.

bVec2 centroid (bXForm xf);

Returns:
the centroid and apply the supplied transform.

int vertexCount ();

Returns:
the vertex count

bVec2 [] vertices ();

Returns:
the vertices in local coordinates.

bVec2 [] worldVertices ();

Returns:
the vertices in world coordinates

bVec2 worldCenter ();

Returns:
The polygon's centroid in world coordinates

bVec2 [] coreVertices ();

Returns:
The core vertices in local coordinates. These vertices represent a smaller polygon that is used for time of impact computations.

bVec2 [] normals ();

Returns:
The edge normal vectors. There is one for each vertex.

void updateSweepRadius (bVec2 center);

Update the sweep radius (maximum radius) as measured from a local center point.

Params:

bVec2 center

the center point to measure from

bool testPoint (bXForm xf, bVec2 p);

Test a point for containment in this shape. This only works for convex shapes.

Params:

bXForm xf	the shape world transform.
bVec2 p	a point in world coordinates.

Returns:
true if the point lies within the shape, false otherwise.

Implements:
blaze.collision.shapes.shape.Shape. testPoint

SegmentCollide testSegment (bXForm xf, ref float lambda, ref bVec2 normal, Segment segment, float maxLambda);

Perform a ray cast against this shape.

Params:

bXForm xf	the shape world transform.
float lambda	returns the hit fraction. You can use this to compute the contact point p = (1 - lambda) * segment.p1 + lambda * segment.p2
bVec2 normal	returns the normal at the contact point. If there is no intersection, the normal is not set.
Segment segment	defines the begin and end point of the ray cast.
float maxLambda	a number typically in the range [0,1].

Returns:
a SegmentCollide representing the collision between this shape and the segment

Implements:
blaze.collision.shapes.shape.Shape. testSegment

void computeAABB (ref AABB aabb, bXForm xf);

Given a transform, compute the associated axis aligned bounding box for this shape. This does not modify the shape's AABB

Params:

AABB aabb	returns the axis aligned box.
bXForm xf	the world transform of the shape.

Implements:
blaze.collision.shapes.shape.Shape. computeAABB

void computeSweptAABB (bXForm xf1, bXForm xf2);

Given two transforms, compute the associated swept axis aligned bounding box for this shape. This DOES modify the shape's AABB (see bugs)

Params:

bXForm xf1	the world transform of the shape.
bXForm xf2	the velocity of the shape

Implements:
blaze.collision.shapes.shape.Shape. computeSweptAABB

BUGS:
Why is this different from the way Box2d does it? And why does it behave differently from computeAABB?

void computeMass (ref MassData massData);

Compute the mass properties of this shape using its dimensions and density. The inertia tensor is computed about the local origin, not the centroid.

Params:

MassData massData

returns the mass data for this shape.

Implements:
blaze.collision.shapes.shape.Shape. computeMass

bVec2 support (bXForm xf, bVec2 d);

Returns:
The shape's support point (for MPR & GJK)

void triangulate ();

Triangulate the shape in world coordinates. Currently this is only used by the buoyancy solver.

bVec2 computeCentroid (bVec2 [] vs);

Determines the centroid of a polygon

Params:

bVec2 [] vs

the verticies that define the polygon

Returns:
the location of the centroid (probably in local coordinates)

void computeOBB (ref OBB obb, bVec2 [] vs);

Computes the object bounding box for a polygon

Params:

OBB obb	the bounding box that the result is stored in
bVec2 [] vs	the verticies that define the polygon

See Also:
www.geometrictools.com/Documentation/minNumimumAreaRectangle.pdf