EdgeContextFields

Defined in: packages/sigma/src/rendering/edges/types.ts:397

EdgeContext - available to all edge GLSL functions.

This struct is populated in the fragment shader and provides information about the current fragment’s position on the edge.

GLSL definition:

struct EdgeContext {
  float t;                  // Position along path [0, 1]
  float sdf;                // Signed distance from centerline
  vec2 position;            // World position of fragment
  vec2 tangent;             // Path tangent at current point
  vec2 normal;              // Path normal at current point
  float thickness;          // Edge thickness in world units
  float aaWidth;            // Anti-aliasing width
  float edgeLength;         // Total path length
  float tStart;             // Where edge starts (after source node)
  float tEnd;               // Where edge ends (before target node)
  float distanceFromSource; // Arc distance from source
  float distanceToTarget;   // Arc distance to target
};

Properties

aaWidth

aaWidth: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:411

Anti-aliasing width in world units

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distanceFromSource

distanceFromSource: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:419

Arc distance from source node boundary to current position

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distanceToTarget

distanceToTarget: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:421

Arc distance from current position to target node boundary

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edgeLength

edgeLength: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:413

Total arc length of the edge path

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normal

normal: "vec2"

Defined in: packages/sigma/src/rendering/edges/types.ts:407

Unit normal vector at current position (perpendicular to tangent)

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position

position: "vec2"

Defined in: packages/sigma/src/rendering/edges/types.ts:403

World position of the current fragment

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sdf

sdf: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:401

Signed distance from path centerline (negative = left, positive = right)

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t

t: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:399

Position along path [0, 1] where 0 = source, 1 = target

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tangent

tangent: "vec2"

Defined in: packages/sigma/src/rendering/edges/types.ts:405

Unit tangent vector at current position (direction of travel)

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tEnd

tEnd: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:417

Parameter t where edge actually ends (before target node boundary)

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thickness

thickness: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:409

Edge thickness in world units

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tStart

tStart: "float"

Defined in: packages/sigma/src/rendering/edges/types.ts:415

Parameter t where edge actually starts (after source node boundary)