Shader parameter controls

Use // @param to expose a value in Layer Settings. WhimTex creates the uniform and its control; click Apply after changing declarations or code.

Start with a value and a color

// @param float _Amount = 1 [0 .. 1]
// @param color _Tint = #FFAA66

float4 ApplyFX(float2 uv, float4 color)
{
    return float4(lerp(color.rgb, color.rgb * _Tint.rgb, _Amount), color.a);
}

This effect tints RGB without changing alpha. _Amount starts at 1 and its slider spans 0–1. For input textures, coordinate spaces and all parameter types, see the HLSL reference.

Labels and header controls

Directive	Purpose
// @param label(Tint Strength) float _Strength = 1	Give the field a readable label. Quote labels containing parentheses.
hidden on a parameter declaration	Hide its normal body row, without changing its value or HLSL behavior. It can precede or follow label(...).
// @control(_Opacity)	Put one existing parameter before ⋮ in the FX header.
// @header(Lighting)	Add a bold, non-collapsible heading before the next parameter.
// @helpbox(Your hint text.)	Add an informational hint before the next parameter.

Place @control immediately after // @whimtex-effect Category/Name, or on the first line if there is no catalog marker. It supports bool, enum, float, color and float2/3/4. Without hidden, the header and body fields edit the same value. Unsupported types leave the header unchanged. Repeated control directives warn and the last wins.

These directives describe the UI, not the effect: an opacity control does not add blending by itself. Headings and hints without a following parameter are ignored. The metadata is retained in presets and exported code.

Conditional fields and groups

Use @if to show options only for a selected mode:

// @param enum _Mode = 0 { Basic: 0, Advanced: 1 }
// @if _Mode == 1
// @param float _Detail = 0.5 [0 .. 1]
// @param bool _UseExtra = false
// @endif

Conditions accept numeric == and != comparisons against an unconditional float, bool or enum parameter. They cannot be nested. Hidden values still exist and affect HLSL; branch in the shader too if the mode should change its calculation. Preset export retains the conditions.

Group related fields with // @group(Tint; _Parameter) and // @endgroup. The linked parameter must be declared unconditionally inside that group.

Linked type	Header behavior
bool	Checkbox to the left of the title. It changes the value; use @if to hide dependent fields.
enum, float, color, float2/3/4	Compact field on the right, labeled by the group title; dragging a float title adjusts it.
Unsupported or multi-row type	Remains in the body; the header stays plain.

Linked compact fields are removed from the body. hidden does not hide a supported linked header field; unlinked hidden fields stay invisible. When conditions hide every body row, only the header remains. Groups may contain @if, but cannot contain other groups. Use // @group(Advanced) for a plain titled group, or // @group for an untitled border.

Curve defaults

Declare a profile with, for example, // @param curve _Profile = easeInOut.

Default	Shape
linear	Straight from (0,0) to (1,1).
easeInOut	Same endpoints, flattened at both ends.
easeIn / easeOut	Quadratic 0→1 curve with a slow start / finish.
one	Constant 1, with keys at time 0 and 1.

Renaming a parameter

Place // @formerlyserializedas(_OldName) directly before its new // @param declaration. Apply transfers compatible saved values and parameter identity. Repeat the directive for multiple former names and use the new uniform name in HLSL. Preset export keeps the aliases.

Coordinates and time

LayerToLocal(uv) makes procedural shapes follow the layer transform. See the coordinate contract.

FX and Shader Processor cache results when their inputs and parameters are unchanged. Use an explicit parameter for time-dependent effects. Unity time inputs (_Time, _SinTime, _CosTime, _TimeParameters, unity_DeltaTime) are unsupported: they are accepted, but Apply warns and disables caching for that result.