vshape

type Box struct {
	ShapeBase

	// size along each dimension
	Size math32.Vector3

	// number of segments to divide each plane into (enforced to be at least 1) -- may potentially increase rendering quality to have > 1
	Segs math32.Vector3i
}

type Capsule struct {
	ShapeBase

	// height of the cylinder portion
	Height float32

	// radius of the top -- set to 0 to omit top cap
	TopRad float32

	// radius of the bottom -- set to 0 to omit bottom cap
	BotRad float32

	// number of radial segments (32 is a reasonable default for full circle)
	RadialSegs int `min:"1"`

	// number of height segments
	HeightSegs int

	// number of segments in the hemisphere cap ends (16 is a reasonable default)
	CapSegs int

	// starting angle in degrees, relative to -1,0,0 left side starting point
	AngStart float32 `min:"0" max:"360" step:"5"`

	// total angle to generate in degrees (max 360)
	AngLen float32 `min:"0" max:"360" step:"5"`
}

type Cylinder struct {
	ShapeBase

	// height of the cylinder
	Height float32

	// radius of the top -- set to 0 for a cone
	TopRad float32

	// radius of the bottom
	BotRad float32

	// number of radial segments (32 is a reasonable default for full circle)
	RadialSegs int `min:"1"`

	// number of height segments
	HeightSegs int

	// render the top disc
	Top bool

	// render the bottom disc
	Bottom bool

	// starting angle in degrees, relative to -1,0,0 left side starting point
	AngStart float32 `min:"0" max:"360" step:"5"`

	// total angle to generate in degrees (max 360)
	AngLen float32 `min:"0" max:"360" step:"5"`
}

type Lines struct {
	ShapeBase

	// line points (must be 2 or more)
	Points []math32.Vector3

	// line width, Y = height perpendicular to line direction, and X = depth
	Width math32.Vector2

	// optional colors for each point -- actual color interpolates between
	Colors []color.Color

	// if true, connect the first and last points to form a closed shape
	Closed bool
}

type Plane struct {
	ShapeBase

	// axis along which the normal perpendicular to the plane points.  E.g., if the Y axis is specified, then it is a standard X-Z ground plane -- see also NormNeg for whether it is facing in the positive or negative of the given axis.
	NormAxis math32.Dims

	// if false, the plane normal facing in the positive direction along specified NormAxis, otherwise it faces in the negative if true
	NormNeg bool

	// 2D size of plane
	Size math32.Vector2

	// number of segments to divide plane into (enforced to be at least 1) -- may potentially increase rendering quality to have > 1
	Segs math32.Vector2i

	// offset from origin along direction of normal to the plane
	Offset float32
}

type Shape interface {
	// N returns number of vertex, index points in this shape element
	N() (nVtx, nIndex int)

	// Offs returns starting offset for verticies, indexes in full shape array,
	// in terms of points, not floats
	Offs() (vtxOff, idxOff int)

	// SetOffs sets starting offset for verticies, indexes in full shape array,
	// in terms of points, not floats
	SetOffs(vtxOff, idxOff int)

	// Set sets points in given allocated arrays
	Set(vtxAry, normAry, texAry math32.ArrayF32, idxAry math32.ArrayU32)

	// BBox returns the bounding box for the shape, typically centered around 0
	// This is only valid after Set has been called.
	BBox() math32.Box3
}

type ShapeBase struct {

	// vertex offset, in points
	VtxOff int

	// index offset, in points
	IndexOff int

	// cubic bounding box in local coords
	CBBox math32.Box3

	// all shapes take a 3D position offset to enable composition
	Pos math32.Vector3
}

type ShapeGroup struct {
	ShapeBase

	// list of shapes in group
	Shapes []Shape
}

type Sphere struct {
	ShapeBase

	// radius of the sphere
	Radius float32

	// number of segments around the width of the sphere (32 is reasonable default for full circle)
	WidthSegs int `min:"3"`

	// number of height segments (32 is reasonable default for full height)
	HeightSegs int `min:"3"`

	// starting radial angle in degrees, relative to -1,0,0 left side starting point
	AngStart float32 `min:"0" max:"360" step:"5"`

	// total radial angle to generate in degrees (max = 360)
	AngLen float32 `min:"0" max:"360" step:"5"`

	// starting elevation (height) angle in degrees - 0 = top of sphere, and Pi is bottom
	ElevStart float32 `min:"0" max:"180" step:"5"`

	// total angle to generate in degrees (max = 180)
	ElevLen float32 `min:"0" max:"180" step:"5"`
}

type Torus struct {
	ShapeBase

	// larger radius of the torus ring
	Radius float32

	// radius of the solid tube
	TubeRadius float32

	// number of segments around the radius of the torus (32 is reasonable default for full circle)
	RadialSegs int `min:"1"`

	// number of segments for the tube itself (32 is reasonable default for full height)
	TubeSegs int `min:"1"`

	// starting radial angle in degrees relative to 1,0,0 starting point
	AngStart float32 `min:"0" max:"360" step:"5"`

	// total radial angle to generate in degrees (max = 360)
	AngLen float32 `min:"0" max:"360" step:"5"`
}