## reb Class REB_TrapShapeCircleCatacaustic

```Object
common:Generic
common:TrapShape
reb:REB_TrapShapeCircleCatacaustic
```

`class TrapShape:REB_TrapShapeCircleCatacaustic`

This shape uses the circle catacaustic function.

This variant of the function has a signed and absolute value version of the distance. The function also has a complex conjugate. The transformed value is the complex return value of the function.

Ultra Fractal Source
``` class REB_TrapShapeCircleCatacaustic(common.ulb:TrapShape) {
; This shape uses the circle catacaustic function.<br>
; <p>
; This variant of the function has a signed and absolute value
; version of the distance. The function also has a complex conjugate.
; The transformed value is the complex return value of the function.
public:
import "common.ulb"

; Constructor
func REB_TrapShapeCircleCatacaustic(Generic pparent)
TrapShape.TrapShape(pparent)
endfunc

; Call this for each iteration being trapped.
float func Iterate(complex pz)
TrapShape.Iterate(pz)
int sgn = 1
if @sgn
sgn = -1
endif
float theta = 0
float d =  0
float af1 = 0
float af2 = 0
complex as = 0
theta = atan2(pz)
af1 = 2*@b*(1-3*2*@b*cos(theta)+2*2*@b*cos(theta)^3)/(-(1+2*(2*@b)^2)+3*2*@b*cos(theta))
af2 = 2*(2*@b)^2*sin(theta)^3/(1+2*(2*@b)^2-3*2*@b*cos(theta))
as = @a*(af1 + sgn*flip(af2))
if @absval
d = abs(cabs(pz) - cabs(as))
else
d = cabs(pz - (as))
endif
m_LastZ = as
return d
endfunc

default:
title = "Circle Catacaustic"
int param v_trapshapecirclecatacaustic
caption = "Version (Trap Shape Circle Catacaustic)"
default = 101
hint = "This version parameter is used to detect when a change has been made to the formula that is incompatible with the previous version. When that happens, this field will reflect the old version number to alert you to the fact that an alternate rendering is being used."
visible = @v_trapshapecirclecatacaustic < 101
endparam

float param a
caption = "Polar parameter"
default = 0.2
hint = "Affects spread and scale of trap"
endparam
float param b
caption = "2nd Polar parameter"
default = 1.0
hint = "Affects spread and scale of trap"
endparam
bool param sgn
caption = "Conjugate transform"
default = false
endparam
param absval
caption = "Absolute Value"
default = false
endparam
}
```

Constructor Summary
`REB_TrapShapeCircleCatacaustic()`

`REB_TrapShapeCircleCatacaustic(Generic pparent)`
Constructor

Method Summary
` float` `Iterate(complex pz)`
Call this for each iteration being trapped.

Methods inherited from class common:TrapShape
`GetColorChannel, GetTextureValue, GetTransformedPoint, Init, IterateSilent, SetThreshold`

Methods inherited from class common:Generic
`GetParent`

Methods inherited from class Object

Constructor Detail

### REB_TrapShapeCircleCatacaustic

`public REB_TrapShapeCircleCatacaustic(Generic pparent)`
Constructor

### REB_TrapShapeCircleCatacaustic

`public REB_TrapShapeCircleCatacaustic()`
Method Detail

### Iterate

`public float Iterate(complex pz)`
Call this for each iteration being trapped.

Overrides:
`Iterate` in class `TrapShape`