SPIR-V Built-In

PointCoord

Fragment coordinates in screen-space within a point primitive
PointCoord

Decorating a variable with the PointCoord built-in decoration will make that variable contain the coordinate of the current fragment within the point being rasterized, normalized to the size of the point with origin in the upper left corner of the point, as described in Basic Point Rasterization. If the primitive the fragment shader invocation belongs to is not a point, then the variable decorated with PointCoord contains an undefined: value.

Depending on how the point is rasterized, PointCoord may never reach (0,0) or (1,1).

Valid Usage

VUID-PointCoord-PointCoord-04311

The PointCoord decoration must be used only within the Fragment Execution Model

VUID-PointCoord-PointCoord-04312

The variable decorated with PointCoord must be declared using the Input Storage Class

VUID-PointCoord-PointCoord-04313

The variable decorated with PointCoord must be declared as a two-component vector of 32-bit floating-point values