LayerContext

Defined in: packages/sigma/src/rendering/nodes/types.ts:176

Context provided to a fragment layer’s GLSL code via the global context struct. This struct is populated by the generator before calling any layer functions.

GLSL definition:

struct LayerContext {
  float sdf;             // Signed distance from shape boundary
  vec2 uv;               // UV coordinates [-1, 1]
  float shapeSize;       // Effective shape radius in UV space
  float aaWidth;         // Anti-aliasing width
  float pixelSize;       // Node diameter in screen pixels
  float correctionRatio; // Scaling factor for consistent rendering
  float pixelToUV;       // Conversion: pixels * pixelToUV = UV units
};
LayerContext context;  // Global instance

Properties

aaWidth

aaWidth: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:198

The antialiasing width in UV space. Use this for smooth transitions between internal borders/regions.

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correctionRatio

correctionRatio: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:210

Scaling factor for consistent rendering across zoom levels. Useful for advanced effects that need to compensate for camera zoom.

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pixelSize

pixelSize: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:204

The node diameter in screen pixels. Useful for pixel-mode border calculations.

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pixelToUV

pixelToUV: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:217

Conversion factor from screen pixels to UV units. Multiply a pixel value by this to get the equivalent size in UV space. Use this for pixel-mode border sizes or any pixel-based measurements.

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sdf

sdf: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:181

The signed distance field value at this fragment. Negative inside the shape, zero at boundary, positive outside.

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shapeSize

shapeSize: "float"

Defined in: packages/sigma/src/rendering/nodes/types.ts:192

The effective shape size in UV space (1.0 - aaWidth). This is the radius where the solid shape ends, before the AA band.

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uv

uv: "vec2"

Defined in: packages/sigma/src/rendering/nodes/types.ts:186

Normalized UV coordinates in [-1, 1] range, with (0,0) at center.