GRADIENT_CIRCLE

Vertex format for gradient circle shader.

• UV0: Quad-local UV (0..1). Shader remaps this to -1,1 to evaluate circle SDF.

• OuterColor: Packed outer ring RG/BA channels in UV1.x/UV1.y.

• InnerColor: Packed inner ring RG/BA channels in UV2.x/UV2.y.

• InnerRatio: Inner radius ratio in 0,1 (innerRadius / outerRadius).